From b0b77b9ca572ed95bf24c222931f5f3da8982b89 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Sun, 8 Jul 2012 19:33:10 -0400
Subject: [PATCH 01/38] caf: support either old or new style ALAC magic kuki
 chunk

---
 libavformat/cafdec.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index d5ee9be92a..4a04cb0b05 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -121,18 +121,40 @@ static int read_kuki_chunk(AVFormatContext *s, int64_t size)
     } else if (st->codec->codec_id == CODEC_ID_ALAC) {
 #define ALAC_PREAMBLE 12
 #define ALAC_HEADER   36
-        if (size < ALAC_PREAMBLE + ALAC_HEADER) {
+#define ALAC_NEW_KUKI 24
+        uint8_t preamble[12];
+        if (size < ALAC_NEW_KUKI || size > ALAC_PREAMBLE + ALAC_HEADER) {
             av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
             avio_skip(pb, size);
             return AVERROR_INVALIDDATA;
         }
-        avio_skip(pb, ALAC_PREAMBLE);
+        avio_read(pb, preamble, ALAC_PREAMBLE);
+
         st->codec->extradata = av_mallocz(ALAC_HEADER + FF_INPUT_BUFFER_PADDING_SIZE);
         if (!st->codec->extradata)
             return AVERROR(ENOMEM);
-        avio_read(pb, st->codec->extradata, ALAC_HEADER);
+
+        /* For the old style cookie, we skip 12 bytes, then read 36 bytes.
+         * The new style cookie only contains the last 24 bytes of what was
+         * 36 bytes in the old style cookie, so we fabricate the first 12 bytes
+         * in that case to maintain compatibility. */
+        if (!memcmp(&preamble[4], "frmaalac", 8)) {
+            if (size < ALAC_PREAMBLE + ALAC_HEADER) {
+                av_log(s, AV_LOG_ERROR, "invalid ALAC magic cookie\n");
+                av_freep(&st->codec->extradata);
+                return AVERROR_INVALIDDATA;
+            }
+            avio_read(pb, st->codec->extradata, ALAC_HEADER);
+            avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
+        } else {
+            AV_WB32(st->codec->extradata, 36);
+            memcpy(&st->codec->extradata[4], "alac", 4);
+            AV_WB32(&st->codec->extradata[8], 0);
+            memcpy(&st->codec->extradata[12], preamble, 12);
+            avio_read(pb, &st->codec->extradata[24], ALAC_NEW_KUKI - 12);
+            avio_skip(pb, size - ALAC_NEW_KUKI);
+        }
         st->codec->extradata_size = ALAC_HEADER;
-        avio_skip(pb, size - ALAC_PREAMBLE - ALAC_HEADER);
     } else {
         st->codec->extradata = av_mallocz(size + FF_INPUT_BUFFER_PADDING_SIZE);
         if (!st->codec->extradata)

From f5a9c35f886508b851011b7dd4ec18cc67b57d37 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 14:10:52 -0400
Subject: [PATCH 02/38] caf: fix 'pakt' chunk parsing

according to the CAF specification:
"... the value for mChunkSize can be greater than the actual valid content
of the packet table chunk"
---
 libavformat/cafdec.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index 4a04cb0b05..90e97a10bd 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -192,10 +192,11 @@ static int read_pakt_chunk(AVFormatContext *s, int64_t size)
         st->duration += caf->frames_per_packet ? caf->frames_per_packet : ff_mp4_read_descr_len(pb);
     }
 
-    if (avio_tell(pb) - ccount != size) {
+    if (avio_tell(pb) - ccount > size) {
         av_log(s, AV_LOG_ERROR, "error reading packet table\n");
-        return -1;
+        return AVERROR_INVALIDDATA;
     }
+    avio_skip(pb, ccount + size - avio_tell(pb));
 
     caf->num_bytes = pos;
     return 0;

From c0196a14b9f0f920da30bc30a8887fae9050a4b3 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 14:16:37 -0400
Subject: [PATCH 03/38] caf: use int64_t for num_packets

It is used to store a value read by avio_rb64().
---
 libavformat/cafdec.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index 90e97a10bd..15a1e2207c 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -172,8 +172,8 @@ static int read_pakt_chunk(AVFormatContext *s, int64_t size)
     AVIOContext *pb = s->pb;
     AVStream *st      = s->streams[0];
     CaffContext *caf  = s->priv_data;
-    int64_t pos = 0, ccount;
-    int num_packets, i;
+    int64_t pos = 0, ccount, num_packets;
+    int i;
 
     ccount = avio_tell(pb);
 

From 3bab7cd12802dc5abf2c5cc6dec49e9e249ce204 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Sat, 7 Apr 2012 12:40:50 -0400
Subject: [PATCH 04/38] avformat: move 'chan' tag parsing to mov_chan.c to
 share with the CAF demuxer

---
 libavformat/cafdec.c   |  6 ++++++
 libavformat/mov.c      | 39 +----------------------------------
 libavformat/mov_chan.c | 46 +++++++++++++++++++++++++++++++++++++++++-
 libavformat/mov_chan.h | 19 +++++++++--------
 4 files changed, 63 insertions(+), 47 deletions(-)

diff --git a/libavformat/cafdec.c b/libavformat/cafdec.c
index 15a1e2207c..6c40b1b229 100644
--- a/libavformat/cafdec.c
+++ b/libavformat/cafdec.c
@@ -29,6 +29,7 @@
 #include "internal.h"
 #include "riff.h"
 #include "isom.h"
+#include "mov_chan.h"
 #include "libavutil/intreadwrite.h"
 #include "libavutil/intfloat.h"
 #include "libavutil/dict.h"
@@ -266,6 +267,11 @@ static int read_header(AVFormatContext *s)
             found_data = 1;
             break;
 
+        case MKBETAG('c','h','a','n'):
+            if ((ret = ff_mov_read_chan(s, st, size)) < 0)
+                return ret;
+            break;
+
         /* magic cookie chunk */
         case MKBETAG('k','u','k','i'):
             if (read_kuki_chunk(s, size))
diff --git a/libavformat/mov.c b/libavformat/mov.c
index 647fd0eb9e..59d7b1a7e4 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -575,10 +575,6 @@ static int mov_read_dec3(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
 {
     AVStream *st;
-    uint8_t av_unused version;
-    uint32_t av_unused flags;
-    uint32_t layout_tag, bitmap, num_descr, label_mask;
-    int i;
 
     if (c->fc->nb_streams < 1)
         return 0;
@@ -587,40 +583,7 @@ static int mov_read_chan(MOVContext *c, AVIOContext *pb, MOVAtom atom)
     if (atom.size < 16)
         return 0;
 
-    version = avio_r8(pb);
-    flags   = avio_rb24(pb);
-
-    layout_tag = avio_rb32(pb);
-    bitmap     = avio_rb32(pb);
-    num_descr  = avio_rb32(pb);
-
-    if (atom.size < 16ULL + num_descr * 20ULL)
-        return 0;
-
-    av_dlog(c->fc, "chan: size=%ld version=%u flags=%u layout=%u bitmap=%u num_descr=%u\n",
-            atom.size, version, flags, layout_tag, bitmap, num_descr);
-
-    label_mask = 0;
-    for (i = 0; i < num_descr; i++) {
-        uint32_t label;
-        label     = avio_rb32(pb);          // mChannelLabel
-        avio_rb32(pb);                      // mChannelFlags
-        avio_rl32(pb);                      // mCoordinates[0]
-        avio_rl32(pb);                      // mCoordinates[1]
-        avio_rl32(pb);                      // mCoordinates[2]
-        if (layout_tag == 0) {
-            uint32_t mask_incr = ff_mov_get_channel_label(label);
-            if (mask_incr == 0) {
-                label_mask = 0;
-                break;
-            }
-            label_mask |= mask_incr;
-        }
-    }
-    if (layout_tag == 0)
-        st->codec->channel_layout = label_mask;
-    else
-        st->codec->channel_layout = ff_mov_get_channel_layout(layout_tag, bitmap);
+    ff_mov_read_chan(c->fc, st, atom.size - 4);
 
     return 0;
 }
diff --git a/libavformat/mov_chan.c b/libavformat/mov_chan.c
index edd5f6c4da..c0b57119d1 100644
--- a/libavformat/mov_chan.c
+++ b/libavformat/mov_chan.c
@@ -477,7 +477,7 @@ uint64_t ff_mov_get_channel_layout(uint32_t tag, uint32_t bitmap)
     return layout_map[i].layout;
 }
 
-uint32_t ff_mov_get_channel_label(uint32_t label)
+static uint32_t mov_get_channel_label(uint32_t label)
 {
     if (label == 0)
         return 0;
@@ -542,3 +542,47 @@ uint32_t ff_mov_get_channel_layout_tag(enum CodecID codec_id,
 
     return tag;
 }
+
+int ff_mov_read_chan(AVFormatContext *s, AVStream *st, int64_t size)
+{
+    AVIOContext *pb = s->pb;
+    uint32_t layout_tag, bitmap, num_descr, label_mask;
+    int i;
+
+    if (size < 12)
+        return AVERROR_INVALIDDATA;
+
+    layout_tag = avio_rb32(pb);
+    bitmap     = avio_rb32(pb);
+    num_descr  = avio_rb32(pb);
+
+    av_dlog(s, "chan: layout=%u bitmap=%u num_descr=%u\n",
+            layout_tag, bitmap, num_descr);
+
+    if (size < 12ULL + num_descr * 20ULL)
+        return 0;
+
+    label_mask = 0;
+    for (i = 0; i < num_descr; i++) {
+        uint32_t label;
+        label     = avio_rb32(pb);          // mChannelLabel
+        avio_rb32(pb);                      // mChannelFlags
+        avio_rl32(pb);                      // mCoordinates[0]
+        avio_rl32(pb);                      // mCoordinates[1]
+        avio_rl32(pb);                      // mCoordinates[2]
+        if (layout_tag == 0) {
+            uint32_t mask_incr = mov_get_channel_label(label);
+            if (mask_incr == 0) {
+                label_mask = 0;
+                break;
+            }
+            label_mask |= mask_incr;
+        }
+    }
+    if (layout_tag == 0)
+            st->codec->channel_layout = label_mask;
+    else
+        st->codec->channel_layout = ff_mov_get_channel_layout(layout_tag, bitmap);
+
+    return 0;
+}
diff --git a/libavformat/mov_chan.h b/libavformat/mov_chan.h
index bd6adf6ad4..0897cd92dd 100644
--- a/libavformat/mov_chan.h
+++ b/libavformat/mov_chan.h
@@ -29,6 +29,7 @@
 #include <stdint.h>
 
 #include "libavcodec/avcodec.h"
+#include "avformat.h"
 
 /**
  * Get the channel layout for the specified channel layout tag.
@@ -39,14 +40,6 @@
  */
 uint64_t ff_mov_get_channel_layout(uint32_t tag, uint32_t bitmap);
 
-/**
- * Get the channel layout for the specified channel label.
- *
- * @param[in]  label   channel label
- * @return             channel layout mask fragment
- */
-uint32_t ff_mov_get_channel_label(uint32_t label);
-
 /**
  * Get the channel layout tag for the specified codec id and channel layout.
  * If the layout tag was not found, use a channel bitmap if possible.
@@ -60,4 +53,14 @@ uint32_t ff_mov_get_channel_layout_tag(enum CodecID codec_id,
                                        uint64_t channel_layout,
                                        uint32_t *bitmap);
 
+/**
+ * Read 'chan' tag from the input stream.
+ *
+ * @param s     AVFormatContext
+ * @param st    The stream to set codec values for
+ * @param size  Remaining size in the 'chan' tag
+ * @return      0 if ok, or negative AVERROR code on failure
+ */
+int ff_mov_read_chan(AVFormatContext *s, AVStream *st, int64_t size);
+
 #endif /* AVFORMAT_MOV_CHAN_H */

From 2ac17375830ed793eccabfaf54d3b0448baea2ea Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:10:02 -0400
Subject: [PATCH 05/38] alac: clean up and update comments leftover from
 reverse-engineering

---
 libavcodec/alac.c | 49 +++++++++++++++++------------------------------
 1 file changed, 18 insertions(+), 31 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index ab9fb81d87..699b86ad6f 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -70,19 +70,16 @@ typedef struct {
 
     int32_t *extra_bits_buffer[MAX_CHANNELS];
 
-    /* stuff from setinfo */
-    uint32_t setinfo_max_samples_per_frame; /* 0x1000 = 4096 */    /* max samples per frame? */
-    uint8_t setinfo_sample_size; /* 0x10 */
-    uint8_t setinfo_rice_historymult; /* 0x28 */
-    uint8_t setinfo_rice_initialhistory; /* 0x0a */
-    uint8_t setinfo_rice_kmodifier; /* 0x0e */
-    /* end setinfo stuff */
+    uint32_t setinfo_max_samples_per_frame;
+    uint8_t setinfo_sample_size;
+    uint8_t setinfo_rice_historymult;
+    uint8_t setinfo_rice_initialhistory;
+    uint8_t setinfo_rice_kmodifier;
 
     int extra_bits;                         /**< number of extra bits beyond 16-bit */
 } ALACContext;
 
 static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsamplesize){
-    /* read x - number of 1s before 0 represent the rice */
     int x = get_unary_0_9(gb);
 
     if (x > 8) { /* RICE THRESHOLD */
@@ -109,14 +106,13 @@ static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsam
 }
 
 static void bastardized_rice_decompress(ALACContext *alac,
-                                 int32_t *output_buffer,
-                                 int output_size,
-                                 int readsamplesize, /* arg_10 */
-                                 int rice_initialhistory, /* arg424->b */
-                                 int rice_kmodifier, /* arg424->d */
-                                 int rice_historymult, /* arg424->c */
-                                 int rice_kmodifier_mask /* arg424->e */
-        )
+                                        int32_t *output_buffer,
+                                        int output_size,
+                                        int readsamplesize,
+                                        int rice_initialhistory,
+                                        int rice_kmodifier,
+                                        int rice_historymult,
+                                        int rice_kmodifier_mask)
 {
     int output_count;
     unsigned int history = rice_initialhistory;
@@ -203,10 +199,8 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         return;
     }
 
-    if (predictor_coef_num == 0x1f) { /* 11111 - max value of predictor_coef_num */
-      /* second-best case scenario for fir decompression,
-       * error describes a small difference from the previous sample only
-       */
+    if (predictor_coef_num == 31) {
+        /* simple 1st-order prediction */
         if (output_size <= 1)
             return;
         for (i = 0; i < output_size - 1; i++) {
@@ -231,9 +225,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
             buffer_out[i+1] = val;
         }
 
-    /* 4 and 8 are very common cases (the only ones i've seen). these
-     * should be unrolled and optimized
-     */
+    /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
     /* general case */
     if (predictor_coef_num > 0) {
@@ -371,14 +363,10 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         return AVERROR_INVALIDDATA;
     }
 
-    /* 2^result = something to do with output waiting.
-     * perhaps matters if we read > 1 frame in a pass?
-     */
-    skip_bits(&alac->gb, 4);
+    skip_bits(&alac->gb, 4);  /* element instance tag */
+    skip_bits(&alac->gb, 12); /* unused header bits */
 
-    skip_bits(&alac->gb, 12); /* unknown, skip 12 bits */
-
-    /* the output sample size is stored soon */
+    /* the number of output samples is stored in the frame */
     hassize = get_bits1(&alac->gb);
 
     alac->extra_bits = get_bits(&alac->gb, 2) << 3;
@@ -578,7 +566,6 @@ static int alac_set_info(ALACContext *alac)
 
     bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
 
-    /* buffer size / 2 ? */
     alac->setinfo_max_samples_per_frame = bytestream2_get_be32u(&gb);
     if (alac->setinfo_max_samples_per_frame >= UINT_MAX/4){
         av_log(alac->avctx, AV_LOG_ERROR,

From 836e8b9ba0d80ce03b0664f97245f8f3ac43d145 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:23:47 -0400
Subject: [PATCH 06/38] alac: cosmetics: rename some ALACContext parameters

---
 libavcodec/alac.c | 127 +++++++++++++++++++++++-----------------------
 1 file changed, 63 insertions(+), 64 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 699b86ad6f..4848ea218e 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -37,7 +37,7 @@
  *  8bit  sample size
  *  8bit  history mult         (40)
  *  8bit  initial history      (14)
- *  8bit  kmodifier            (10)
+ *  8bit  rice param limit     (10)
  *  8bit  channels
  * 16bit  maxRun               (255)
  * 32bit  max coded frame size (0 means unknown)
@@ -61,20 +61,18 @@ typedef struct {
     AVFrame frame;
     GetBitContext gb;
 
-    int numchannels;
+    int channels;
 
     /* buffers */
-    int32_t *predicterror_buffer[MAX_CHANNELS];
-
-    int32_t *outputsamples_buffer[MAX_CHANNELS];
-
+    int32_t *predict_error_buffer[MAX_CHANNELS];
+    int32_t *output_samples_buffer[MAX_CHANNELS];
     int32_t *extra_bits_buffer[MAX_CHANNELS];
 
-    uint32_t setinfo_max_samples_per_frame;
-    uint8_t setinfo_sample_size;
-    uint8_t setinfo_rice_historymult;
-    uint8_t setinfo_rice_initialhistory;
-    uint8_t setinfo_rice_kmodifier;
+    uint32_t max_samples_per_frame;
+    uint8_t  sample_size;
+    uint8_t  rice_history_mult;
+    uint8_t  rice_initial_history;
+    uint8_t  rice_limit;
 
     int extra_bits;                         /**< number of extra bits beyond 16-bit */
 } ALACContext;
@@ -109,13 +107,13 @@ static void bastardized_rice_decompress(ALACContext *alac,
                                         int32_t *output_buffer,
                                         int output_size,
                                         int readsamplesize,
-                                        int rice_initialhistory,
-                                        int rice_kmodifier,
-                                        int rice_historymult,
+                                        int rice_initial_history,
+                                        int rice_limit,
+                                        int rice_history_mult,
                                         int rice_kmodifier_mask)
 {
     int output_count;
-    unsigned int history = rice_initialhistory;
+    unsigned int history = rice_initial_history;
     int sign_modifier = 0;
 
     for (output_count = 0; output_count < output_size; output_count++) {
@@ -128,7 +126,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
-        x= decode_scalar(&alac->gb, k, rice_kmodifier, readsamplesize);
+        x= decode_scalar(&alac->gb, k, rice_limit, readsamplesize);
 
         x_modified = sign_modifier + x;
         final_val = (x_modified + 1) / 2;
@@ -139,8 +137,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
         sign_modifier = 0;
 
         /* now update the history */
-        history += x_modified * rice_historymult
-                   - ((history * rice_historymult) >> 9);
+        history += x_modified * rice_history_mult -
+                    ((history * rice_history_mult) >> 9);
 
         if (x_modified > 0xffff)
             history = 0xffff;
@@ -154,7 +152,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
 
-            block_size= decode_scalar(&alac->gb, k, rice_kmodifier, 16);
+            block_size = decode_scalar(&alac->gb, k, rice_limit, 16);
 
             if (block_size > 0) {
                 if(block_size >= output_size - output_count){
@@ -377,12 +375,13 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     if (hassize) {
         /* now read the number of samples as a 32bit integer */
         outputsamples = get_bits_long(&alac->gb, 32);
-        if(outputsamples > alac->setinfo_max_samples_per_frame){
-            av_log(avctx, AV_LOG_ERROR, "outputsamples %d > %d\n", outputsamples, alac->setinfo_max_samples_per_frame);
+        if (outputsamples > alac->max_samples_per_frame) {
+            av_log(avctx, AV_LOG_ERROR, "outputsamples %d > %d\n",
+                   outputsamples, alac->max_samples_per_frame);
             return -1;
         }
     } else
-        outputsamples = alac->setinfo_max_samples_per_frame;
+        outputsamples = alac->max_samples_per_frame;
 
     /* get output buffer */
     if (outputsamples > INT32_MAX) {
@@ -395,7 +394,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         return ret;
     }
 
-    readsamplesize = alac->setinfo_sample_size - alac->extra_bits + channels - 1;
+    readsamplesize = alac->sample_size - alac->extra_bits + channels - 1;
     if (readsamplesize > MIN_CACHE_BITS) {
         av_log(avctx, AV_LOG_ERROR, "readsamplesize too big (%d)\n", readsamplesize);
         return -1;
@@ -432,13 +431,13 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         }
         for (ch = 0; ch < channels; ch++) {
             bastardized_rice_decompress(alac,
-                                        alac->predicterror_buffer[ch],
+                                        alac->predict_error_buffer[ch],
                                         outputsamples,
                                         readsamplesize,
-                                        alac->setinfo_rice_initialhistory,
-                                        alac->setinfo_rice_kmodifier,
-                                        ricemodifier[ch] * alac->setinfo_rice_historymult / 4,
-                                        (1 << alac->setinfo_rice_kmodifier) - 1);
+                                        alac->rice_initial_history,
+                                        alac->rice_limit,
+                                        ricemodifier[ch] * alac->rice_history_mult / 4,
+                                        (1 << alac->rice_limit) - 1);
 
             /* adaptive FIR filter */
             if (prediction_type[ch] == 15) {
@@ -449,16 +448,16 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
                  * However, this prediction type is not currently used by the
                  * reference encoder.
                  */
-                predictor_decompress_fir_adapt(alac->predicterror_buffer[ch],
-                                               alac->predicterror_buffer[ch],
+                predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
+                                               alac->predict_error_buffer[ch],
                                                outputsamples, readsamplesize,
                                                NULL, 31, 0);
             } else if (prediction_type[ch] > 0) {
                 av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
                        prediction_type[ch]);
             }
-            predictor_decompress_fir_adapt(alac->predicterror_buffer[ch],
-                                           alac->outputsamples_buffer[ch],
+            predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
+                                           alac->output_samples_buffer[ch],
                                            outputsamples, readsamplesize,
                                            predictor_coef_table[ch],
                                            predictor_coef_num[ch],
@@ -468,8 +467,8 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         /* not compressed, easy case */
         for (i = 0; i < outputsamples; i++) {
             for (ch = 0; ch < channels; ch++) {
-                alac->outputsamples_buffer[ch][i] = get_sbits_long(&alac->gb,
-                                                                   alac->setinfo_sample_size);
+                alac->output_samples_buffer[ch][i] = get_sbits_long(&alac->gb,
+                                                                    alac->sample_size);
             }
         }
         alac->extra_bits = 0;
@@ -480,35 +479,35 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         av_log(avctx, AV_LOG_ERROR, "Error : Wrong End Of Frame\n");
 
     if (channels == 2 && interlacing_leftweight) {
-        decorrelate_stereo(alac->outputsamples_buffer, outputsamples,
+        decorrelate_stereo(alac->output_samples_buffer, outputsamples,
                            interlacing_shift, interlacing_leftweight);
     }
 
     if (alac->extra_bits) {
-        append_extra_bits(alac->outputsamples_buffer, alac->extra_bits_buffer,
-                          alac->extra_bits, alac->numchannels, outputsamples);
+        append_extra_bits(alac->output_samples_buffer, alac->extra_bits_buffer,
+                          alac->extra_bits, alac->channels, outputsamples);
     }
 
-    switch(alac->setinfo_sample_size) {
+    switch(alac->sample_size) {
     case 16:
         if (channels == 2) {
-            interleave_stereo_16(alac->outputsamples_buffer,
+            interleave_stereo_16(alac->output_samples_buffer,
                                  (int16_t *)alac->frame.data[0], outputsamples);
         } else {
             int16_t *outbuffer = (int16_t *)alac->frame.data[0];
             for (i = 0; i < outputsamples; i++) {
-                outbuffer[i] = alac->outputsamples_buffer[0][i];
+                outbuffer[i] = alac->output_samples_buffer[0][i];
             }
         }
         break;
     case 24:
         if (channels == 2) {
-            interleave_stereo_24(alac->outputsamples_buffer,
+            interleave_stereo_24(alac->output_samples_buffer,
                                  (int32_t *)alac->frame.data[0], outputsamples);
         } else {
             int32_t *outbuffer = (int32_t *)alac->frame.data[0];
             for (i = 0; i < outputsamples; i++)
-                outbuffer[i] = alac->outputsamples_buffer[0][i] << 8;
+                outbuffer[i] = alac->output_samples_buffer[0][i] << 8;
         }
         break;
     }
@@ -527,9 +526,9 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
     ALACContext *alac = avctx->priv_data;
 
     int ch;
-    for (ch = 0; ch < alac->numchannels; ch++) {
-        av_freep(&alac->predicterror_buffer[ch]);
-        av_freep(&alac->outputsamples_buffer[ch]);
+    for (ch = 0; ch < alac->channels; ch++) {
+        av_freep(&alac->predict_error_buffer[ch]);
+        av_freep(&alac->output_samples_buffer[ch]);
         av_freep(&alac->extra_bits_buffer[ch]);
     }
 
@@ -539,13 +538,13 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
 static int allocate_buffers(ALACContext *alac)
 {
     int ch;
-    for (ch = 0; ch < alac->numchannels; ch++) {
-        int buf_size = alac->setinfo_max_samples_per_frame * sizeof(int32_t);
+    for (ch = 0; ch < alac->channels; ch++) {
+        int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
 
-        FF_ALLOC_OR_GOTO(alac->avctx, alac->predicterror_buffer[ch],
+        FF_ALLOC_OR_GOTO(alac->avctx, alac->predict_error_buffer[ch],
                          buf_size, buf_alloc_fail);
 
-        FF_ALLOC_OR_GOTO(alac->avctx, alac->outputsamples_buffer[ch],
+        FF_ALLOC_OR_GOTO(alac->avctx, alac->output_samples_buffer[ch],
                          buf_size, buf_alloc_fail);
 
         FF_ALLOC_OR_GOTO(alac->avctx, alac->extra_bits_buffer[ch],
@@ -566,18 +565,18 @@ static int alac_set_info(ALACContext *alac)
 
     bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
 
-    alac->setinfo_max_samples_per_frame = bytestream2_get_be32u(&gb);
-    if (alac->setinfo_max_samples_per_frame >= UINT_MAX/4){
+    alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
+    if (alac->max_samples_per_frame >= UINT_MAX/4){
         av_log(alac->avctx, AV_LOG_ERROR,
-               "setinfo_max_samples_per_frame too large\n");
+               "max_samples_per_frame too large\n");
         return AVERROR_INVALIDDATA;
     }
     bytestream2_skipu(&gb, 1);  // compatible version
-    alac->setinfo_sample_size           = bytestream2_get_byteu(&gb);
-    alac->setinfo_rice_historymult      = bytestream2_get_byteu(&gb);
-    alac->setinfo_rice_initialhistory   = bytestream2_get_byteu(&gb);
-    alac->setinfo_rice_kmodifier        = bytestream2_get_byteu(&gb);
-    alac->numchannels                   = bytestream2_get_byteu(&gb);
+    alac->sample_size          = bytestream2_get_byteu(&gb);
+    alac->rice_history_mult    = bytestream2_get_byteu(&gb);
+    alac->rice_initial_history = bytestream2_get_byteu(&gb);
+    alac->rice_limit           = bytestream2_get_byteu(&gb);
+    alac->channels             = bytestream2_get_byteu(&gb);
     bytestream2_get_be16u(&gb); // maxRun
     bytestream2_get_be32u(&gb); // max coded frame size
     bytestream2_get_be32u(&gb); // average bitrate
@@ -603,24 +602,24 @@ static av_cold int alac_decode_init(AVCodecContext * avctx)
         return -1;
     }
 
-    switch (alac->setinfo_sample_size) {
+    switch (alac->sample_size) {
     case 16: avctx->sample_fmt    = AV_SAMPLE_FMT_S16;
              break;
     case 24: avctx->sample_fmt    = AV_SAMPLE_FMT_S32;
              break;
     default: av_log_ask_for_sample(avctx, "Sample depth %d is not supported.\n",
-                                   alac->setinfo_sample_size);
+                                   alac->sample_size);
              return AVERROR_PATCHWELCOME;
     }
 
-    if (alac->numchannels < 1) {
+    if (alac->channels < 1) {
         av_log(avctx, AV_LOG_WARNING, "Invalid channel count\n");
-        alac->numchannels = avctx->channels;
+        alac->channels = avctx->channels;
     } else {
-        if (alac->numchannels > MAX_CHANNELS)
-            alac->numchannels = avctx->channels;
+        if (alac->channels > MAX_CHANNELS)
+            alac->channels = avctx->channels;
         else
-            avctx->channels = alac->numchannels;
+            avctx->channels = alac->channels;
     }
     if (avctx->channels > MAX_CHANNELS) {
         av_log(avctx, AV_LOG_ERROR, "Unsupported channel count: %d\n",

From 6e91f62256db72b056f6bc61106809d3994f8e26 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:30:40 -0400
Subject: [PATCH 07/38] alac: reduce the number of parameters to
 bastardized_rice_decompress()

Use the ALACContext fields directly instead.
---
 libavcodec/alac.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 4848ea218e..8824ae8377 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -107,13 +107,10 @@ static void bastardized_rice_decompress(ALACContext *alac,
                                         int32_t *output_buffer,
                                         int output_size,
                                         int readsamplesize,
-                                        int rice_initial_history,
-                                        int rice_limit,
-                                        int rice_history_mult,
-                                        int rice_kmodifier_mask)
+                                        int rice_history_mult)
 {
     int output_count;
-    unsigned int history = rice_initial_history;
+    unsigned int history = alac->rice_initial_history;
     int sign_modifier = 0;
 
     for (output_count = 0; output_count < output_size; output_count++) {
@@ -126,7 +123,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
-        x= decode_scalar(&alac->gb, k, rice_limit, readsamplesize);
+        x = decode_scalar(&alac->gb, k, alac->rice_limit, readsamplesize);
 
         x_modified = sign_modifier + x;
         final_val = (x_modified + 1) / 2;
@@ -152,7 +149,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
 
-            block_size = decode_scalar(&alac->gb, k, rice_limit, 16);
+            block_size = decode_scalar(&alac->gb, k, alac->rice_limit, 16);
 
             if (block_size > 0) {
                 if(block_size >= output_size - output_count){
@@ -434,10 +431,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
                                         alac->predict_error_buffer[ch],
                                         outputsamples,
                                         readsamplesize,
-                                        alac->rice_initial_history,
-                                        alac->rice_limit,
-                                        ricemodifier[ch] * alac->rice_history_mult / 4,
-                                        (1 << alac->rice_limit) - 1);
+                                        ricemodifier[ch] * alac->rice_history_mult / 4);
 
             /* adaptive FIR filter */
             if (prediction_type[ch] == 15) {

From d9837434a91dbb3632df335414aad538e5b0a6e9 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:33:28 -0400
Subject: [PATCH 08/38] alac: limit the rice param before passing to
 decode_scalar()

reduces the number of parameters to decode_scalar() and slightly simplifies
the code
---
 libavcodec/alac.c | 16 +++++++---------
 1 file changed, 7 insertions(+), 9 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 8824ae8377..76ef4998d6 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -77,17 +77,14 @@ typedef struct {
     int extra_bits;                         /**< number of extra bits beyond 16-bit */
 } ALACContext;
 
-static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsamplesize){
+static inline int decode_scalar(GetBitContext *gb, int k, int readsamplesize)
+{
     int x = get_unary_0_9(gb);
 
     if (x > 8) { /* RICE THRESHOLD */
         /* use alternative encoding */
         x = get_bits(gb, readsamplesize);
-    } else {
-        if (k >= limit)
-            k = limit;
-
-        if (k != 1) {
+    } else if (k != 1) {
             int extrabits = show_bits(gb, k);
 
             /* multiply x by 2^k - 1, as part of their strange algorithm */
@@ -98,7 +95,6 @@ static inline int decode_scalar(GetBitContext *gb, int k, int limit, int readsam
                 skip_bits(gb, k);
             } else
                 skip_bits(gb, k - 1);
-        }
     }
     return x;
 }
@@ -123,7 +119,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
-        x = decode_scalar(&alac->gb, k, alac->rice_limit, readsamplesize);
+        k = FFMIN(k, alac->rice_limit);
+        x = decode_scalar(&alac->gb, k, readsamplesize);
 
         x_modified = sign_modifier + x;
         final_val = (x_modified + 1) / 2;
@@ -148,8 +145,9 @@ static void bastardized_rice_decompress(ALACContext *alac,
             sign_modifier = 1;
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
+            k = FFMIN(k, alac->rice_limit);
 
-            block_size = decode_scalar(&alac->gb, k, alac->rice_limit, 16);
+            block_size = decode_scalar(&alac->gb, k, 16);
 
             if (block_size > 0) {
                 if(block_size >= output_size - output_count){

From a06fdadd97778fe50713c2762714cbd8b0eb81b6 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:34:11 -0400
Subject: [PATCH 09/38] alac: cosmetics: reindent after last commit

---
 libavcodec/alac.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 76ef4998d6..84f7e42373 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -85,16 +85,16 @@ static inline int decode_scalar(GetBitContext *gb, int k, int readsamplesize)
         /* use alternative encoding */
         x = get_bits(gb, readsamplesize);
     } else if (k != 1) {
-            int extrabits = show_bits(gb, k);
+        int extrabits = show_bits(gb, k);
 
-            /* multiply x by 2^k - 1, as part of their strange algorithm */
-            x = (x << k) - x;
+        /* multiply x by 2^k - 1, as part of their strange algorithm */
+        x = (x << k) - x;
 
-            if (extrabits > 1) {
-                x += extrabits - 1;
-                skip_bits(gb, k);
-            } else
-                skip_bits(gb, k - 1);
+        if (extrabits > 1) {
+            x += extrabits - 1;
+            skip_bits(gb, k);
+        } else
+            skip_bits(gb, k - 1);
     }
     return x;
 }

From 6fd8a28b596760b4b0a2f227c54d7315e04c396a Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:42:52 -0400
Subject: [PATCH 10/38] alac: adjust conditions for updating entropy decoder
 history

avoids some unnecessary arithmetic in certain situations
---
 libavcodec/alac.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 84f7e42373..f27992d056 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -131,11 +131,11 @@ static void bastardized_rice_decompress(ALACContext *alac,
         sign_modifier = 0;
 
         /* now update the history */
-        history += x_modified * rice_history_mult -
-                    ((history * rice_history_mult) >> 9);
-
         if (x_modified > 0xffff)
             history = 0xffff;
+        else
+            history += x_modified * rice_history_mult -
+                        ((history * rice_history_mult) >> 9);
 
         /* special case: there may be compressed blocks of 0 */
         if ((history < 128) && (output_count+1 < output_size)) {

From 7e6593e9773773b5f6ad19fe4cdb2334d492493c Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:53:28 -0400
Subject: [PATCH 11/38] alac: eliminate 2 unneeded local variables in
 bastardized_rice_decompress()

x_modified is just unnecessary, and final_val can be removed by simplifying
the unsigned-to-signed conversion.
---
 libavcodec/alac.c | 23 +++++++----------------
 1 file changed, 7 insertions(+), 16 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index f27992d056..2aab84cd2e 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -110,32 +110,23 @@ static void bastardized_rice_decompress(ALACContext *alac,
     int sign_modifier = 0;
 
     for (output_count = 0; output_count < output_size; output_count++) {
-        int32_t x;
-        int32_t x_modified;
-        int32_t final_val;
-
-        /* standard rice encoding */
-        int k; /* size of extra bits */
+        int x, k;
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
         k = FFMIN(k, alac->rice_limit);
         x = decode_scalar(&alac->gb, k, readsamplesize);
-
-        x_modified = sign_modifier + x;
-        final_val = (x_modified + 1) / 2;
-        if (x_modified & 1) final_val *= -1;
-
-        output_buffer[output_count] = final_val;
-
+        x += sign_modifier;
         sign_modifier = 0;
 
+        output_buffer[output_count] = (x >> 1) ^ -(x & 1);
+
         /* now update the history */
-        if (x_modified > 0xffff)
+        if (x > 0xffff)
             history = 0xffff;
         else
-            history += x_modified * rice_history_mult -
-                        ((history * rice_history_mult) >> 9);
+            history +=         x * rice_history_mult -
+                       ((history * rice_history_mult) >> 9);
 
         /* special case: there may be compressed blocks of 0 */
         if ((history < 128) && (output_count+1 < output_size)) {

From 5177413d2043109f3e689e5fbfa79411c0c8e09d Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 10:57:42 -0400
Subject: [PATCH 12/38] alac: conditionally set sign_modifier to 1

It is already unconditionally set to 0 prior to this, so we can modify it
only when needed.
---
 libavcodec/alac.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 2aab84cd2e..0aeb4109b7 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -133,8 +133,6 @@ static void bastardized_rice_decompress(ALACContext *alac,
             int k;
             unsigned int block_size;
 
-            sign_modifier = 1;
-
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
             k = FFMIN(k, alac->rice_limit);
 
@@ -149,8 +147,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
                 output_count += block_size;
             }
 
-            if (block_size > 0xffff)
-                sign_modifier = 0;
+            if (block_size <= 0xffff)
+                sign_modifier = 1;
 
             history = 0;
         }

From 2fc24b3273f69a548531cdeaace8c68ac0f038ef Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:00:16 -0400
Subject: [PATCH 13/38] alac: remove a duplicate local variable

---
 libavcodec/alac.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 0aeb4109b7..74da253cab 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -130,7 +130,6 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
         /* special case: there may be compressed blocks of 0 */
         if ((history < 128) && (output_count+1 < output_size)) {
-            int k;
             unsigned int block_size;
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);

From 91620a04f197917d7272608620961e1145085d69 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:02:48 -0400
Subject: [PATCH 14/38] alac: make block_size signed

It does not need to be unsigned.
---
 libavcodec/alac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 74da253cab..91c94d7400 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -130,7 +130,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
 
         /* special case: there may be compressed blocks of 0 */
         if ((history < 128) && (output_count+1 < output_size)) {
-            unsigned int block_size;
+            int block_size;
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
             k = FFMIN(k, alac->rice_limit);

From 4bcd637dcbae78ab419d61164e80438f5925030d Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:04:56 -0400
Subject: [PATCH 15/38] alac: use sizeof() instead of hardcoded data sizes

---
 libavcodec/alac.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 91c94d7400..483346c255 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -142,7 +142,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
                     av_log(alac->avctx, AV_LOG_ERROR, "invalid zero block size of %d %d %d\n", block_size, output_size, output_count);
                     block_size= output_size - output_count - 1;
                 }
-                memset(&output_buffer[output_count+1], 0, block_size * 4);
+                memset(&output_buffer[output_count + 1], 0,
+                       block_size * sizeof(*output_buffer));
                 output_count += block_size;
             }
 
@@ -176,7 +177,8 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         if (output_size <= 1)
             return;
 
-        memcpy(buffer_out+1, error_buffer+1, (output_size-1) * 4);
+        memcpy(&buffer_out[1], &error_buffer[1],
+               (output_size - 1) * sizeof(*buffer_out));
         return;
     }
 

From 79def4c523a1ebb4222c79f5dbf054d7bb4a5f01 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:07:57 -0400
Subject: [PATCH 16/38] alac: remove unneeded conditionals in
 predictor_decompress_fir_adapt()

---
 libavcodec/alac.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 483346c255..027e094c18 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -199,7 +199,6 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 
     /* read warm-up samples */
-    if (predictor_coef_num > 0)
         for (i = 0; i < predictor_coef_num; i++) {
             int32_t val;
 
@@ -211,7 +210,6 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
     /* general case */
-    if (predictor_coef_num > 0) {
         for (i = predictor_coef_num + 1; i < output_size; i++) {
             int j;
             int sum = 0;
@@ -266,7 +264,6 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
 
             buffer_out++;
         }
-    }
 }
 
 static void decorrelate_stereo(int32_t *buffer[MAX_CHANNELS],

From d0c0bf0d3e1bdb58188a2006bb24d83fae01236b Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:08:59 -0400
Subject: [PATCH 17/38] alac: cosmetics: reindent after last commit

---
 libavcodec/alac.c | 90 +++++++++++++++++++++++------------------------
 1 file changed, 45 insertions(+), 45 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 027e094c18..9a3ca51054 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -199,71 +199,71 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 
     /* read warm-up samples */
-        for (i = 0; i < predictor_coef_num; i++) {
-            int32_t val;
+    for (i = 0; i < predictor_coef_num; i++) {
+        int32_t val;
 
-            val = buffer_out[i] + error_buffer[i+1];
-            val = sign_extend(val, readsamplesize);
-            buffer_out[i+1] = val;
-        }
+        val = buffer_out[i] + error_buffer[i+1];
+        val = sign_extend(val, readsamplesize);
+        buffer_out[i+1] = val;
+    }
 
     /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
     /* general case */
-        for (i = predictor_coef_num + 1; i < output_size; i++) {
-            int j;
-            int sum = 0;
-            int outval;
-            int error_val = error_buffer[i];
-
-            for (j = 0; j < predictor_coef_num; j++) {
-                sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
-                       predictor_coef_table[j];
-            }
+    for (i = predictor_coef_num + 1; i < output_size; i++) {
+        int j;
+        int sum = 0;
+        int outval;
+        int error_val = error_buffer[i];
+
+        for (j = 0; j < predictor_coef_num; j++) {
+            sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
+                   predictor_coef_table[j];
+        }
 
-            outval = (1 << (predictor_quantitization-1)) + sum;
-            outval = outval >> predictor_quantitization;
-            outval = outval + buffer_out[0] + error_val;
-            outval = sign_extend(outval, readsamplesize);
+        outval = (1 << (predictor_quantitization-1)) + sum;
+        outval = outval >> predictor_quantitization;
+        outval = outval + buffer_out[0] + error_val;
+        outval = sign_extend(outval, readsamplesize);
 
-            buffer_out[predictor_coef_num+1] = outval;
+        buffer_out[predictor_coef_num+1] = outval;
 
-            if (error_val > 0) {
-                int predictor_num = predictor_coef_num - 1;
+        if (error_val > 0) {
+            int predictor_num = predictor_coef_num - 1;
 
-                while (predictor_num >= 0 && error_val > 0) {
-                    int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                    int sign = sign_only(val);
+            while (predictor_num >= 0 && error_val > 0) {
+                int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
+                int sign = sign_only(val);
 
-                    predictor_coef_table[predictor_num] -= sign;
+                predictor_coef_table[predictor_num] -= sign;
 
-                    val *= sign; /* absolute value */
+                val *= sign; /* absolute value */
 
-                    error_val -= ((val >> predictor_quantitization) *
-                                  (predictor_coef_num - predictor_num));
+                error_val -= ((val >> predictor_quantitization) *
+                              (predictor_coef_num - predictor_num));
 
-                    predictor_num--;
-                }
-            } else if (error_val < 0) {
-                int predictor_num = predictor_coef_num - 1;
+                predictor_num--;
+            }
+        } else if (error_val < 0) {
+            int predictor_num = predictor_coef_num - 1;
 
-                while (predictor_num >= 0 && error_val < 0) {
-                    int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                    int sign = - sign_only(val);
+            while (predictor_num >= 0 && error_val < 0) {
+                int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
+                int sign = - sign_only(val);
 
-                    predictor_coef_table[predictor_num] -= sign;
+                predictor_coef_table[predictor_num] -= sign;
 
-                    val *= sign; /* neg value */
+                val *= sign; /* neg value */
 
-                    error_val -= ((val >> predictor_quantitization) *
-                                  (predictor_coef_num - predictor_num));
+                error_val -= ((val >> predictor_quantitization) *
+                              (predictor_coef_num - predictor_num));
 
-                    predictor_num--;
-                }
+                predictor_num--;
             }
-
-            buffer_out++;
         }
+
+        buffer_out++;
+    }
 }
 
 static void decorrelate_stereo(int32_t *buffer[MAX_CHANNELS],

From 01880d287be6e2269b92eee8d9dc442532d277ea Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:12:25 -0400
Subject: [PATCH 18/38] alac: simplify 1st order prediction and reading of
 warm-up samples

---
 libavcodec/alac.c | 18 +++++-------------
 1 file changed, 5 insertions(+), 13 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 9a3ca51054..b19973db50 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -186,25 +186,17 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         /* simple 1st-order prediction */
         if (output_size <= 1)
             return;
-        for (i = 0; i < output_size - 1; i++) {
-            int32_t prev_value;
-            int32_t error_value;
-
-            prev_value = buffer_out[i];
-            error_value = error_buffer[i+1];
-            buffer_out[i+1] =
-                sign_extend((prev_value + error_value), readsamplesize);
+        for (i = 1; i < output_size; i++) {
+            buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
+                                        readsamplesize);
         }
         return;
     }
 
     /* read warm-up samples */
     for (i = 0; i < predictor_coef_num; i++) {
-        int32_t val;
-
-        val = buffer_out[i] + error_buffer[i+1];
-        val = sign_extend(val, readsamplesize);
-        buffer_out[i+1] = val;
+        buffer_out[i + 1] = sign_extend(buffer_out[i] + error_buffer[i + 1],
+                                        readsamplesize);
     }
 
     /* NOTE: 4 and 8 are very common cases that could be optimized. */

From abc4376b31b672f8f38c30851cbe1acd016b6e18 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:18:21 -0400
Subject: [PATCH 19/38] alac: reduce the number of local variables needed in
 lpc prediction

---
 libavcodec/alac.c | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index b19973db50..7306e57405 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -204,28 +204,27 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     /* general case */
     for (i = predictor_coef_num + 1; i < output_size; i++) {
         int j;
-        int sum = 0;
-        int outval;
+        int val = 0;
         int error_val = error_buffer[i];
 
         for (j = 0; j < predictor_coef_num; j++) {
-            sum += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
+            val += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
                    predictor_coef_table[j];
         }
 
-        outval = (1 << (predictor_quantitization-1)) + sum;
-        outval = outval >> predictor_quantitization;
-        outval = outval + buffer_out[0] + error_val;
-        outval = sign_extend(outval, readsamplesize);
+        val = (val + (1 << (predictor_quantitization - 1))) >>
+              predictor_quantitization;
+        val += buffer_out[0] + error_val;
 
-        buffer_out[predictor_coef_num+1] = outval;
+        buffer_out[predictor_coef_num + 1] = sign_extend(val, readsamplesize);
 
         if (error_val > 0) {
             int predictor_num = predictor_coef_num - 1;
 
             while (predictor_num >= 0 && error_val > 0) {
-                int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                int sign = sign_only(val);
+                int sign;
+                val  = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
+                sign = sign_only(val);
 
                 predictor_coef_table[predictor_num] -= sign;
 
@@ -240,8 +239,9 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
             int predictor_num = predictor_coef_num - 1;
 
             while (predictor_num >= 0 && error_val < 0) {
-                int val = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                int sign = - sign_only(val);
+                int sign;
+                val  = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
+                sign = -sign_only(val);
 
                 predictor_coef_table[predictor_num] -= sign;
 

From f2515cd629d64484be5747639b485ddad9b6bf85 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 11:33:31 -0400
Subject: [PATCH 20/38] alac: simplify lpc coefficient adaptation

---
 libavcodec/alac.c | 41 ++++++++++-------------------------------
 1 file changed, 10 insertions(+), 31 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 7306e57405..110d2cbcb1 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -206,6 +206,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         int j;
         int val = 0;
         int error_val = error_buffer[i];
+        int error_sign;
 
         for (j = 0; j < predictor_coef_num; j++) {
             val += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
@@ -218,39 +219,17 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
 
         buffer_out[predictor_coef_num + 1] = sign_extend(val, readsamplesize);
 
-        if (error_val > 0) {
-            int predictor_num = predictor_coef_num - 1;
-
-            while (predictor_num >= 0 && error_val > 0) {
+        /* adapt LPC coefficients */
+        error_sign = sign_only(error_val);
+        if (error_sign) {
+            for (j = predictor_coef_num - 1; j >= 0 && error_val * error_sign > 0; j--) {
                 int sign;
-                val  = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                sign = sign_only(val);
-
-                predictor_coef_table[predictor_num] -= sign;
-
-                val *= sign; /* absolute value */
-
+                val  = buffer_out[0] - buffer_out[predictor_coef_num - j];
+                sign = sign_only(val) * error_sign;
+                predictor_coef_table[j] -= sign;
+                val *= sign;
                 error_val -= ((val >> predictor_quantitization) *
-                              (predictor_coef_num - predictor_num));
-
-                predictor_num--;
-            }
-        } else if (error_val < 0) {
-            int predictor_num = predictor_coef_num - 1;
-
-            while (predictor_num >= 0 && error_val < 0) {
-                int sign;
-                val  = buffer_out[0] - buffer_out[predictor_coef_num - predictor_num];
-                sign = -sign_only(val);
-
-                predictor_coef_table[predictor_num] -= sign;
-
-                val *= sign; /* neg value */
-
-                error_val -= ((val >> predictor_quantitization) *
-                              (predictor_coef_num - predictor_num));
-
-                predictor_num--;
+                              (predictor_coef_num - j));
             }
         }
 

From a4ecd4144265368db7cdb112e098a6ab5142557a Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 12:52:30 -0400
Subject: [PATCH 21/38] alac: use index into buffer_out instead of incrementing
 the pointer

---
 libavcodec/alac.c | 14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 110d2cbcb1..ba30bef7ea 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -202,29 +202,29 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
     /* general case */
-    for (i = predictor_coef_num + 1; i < output_size; i++) {
+    for (i = predictor_coef_num; i < output_size - 1; i++) {
         int j;
         int val = 0;
-        int error_val = error_buffer[i];
+        int error_val = error_buffer[i + 1];
         int error_sign;
 
         for (j = 0; j < predictor_coef_num; j++) {
-            val += (buffer_out[predictor_coef_num-j] - buffer_out[0]) *
+            val += (buffer_out[i - j] - buffer_out[i - predictor_coef_num]) *
                    predictor_coef_table[j];
         }
 
         val = (val + (1 << (predictor_quantitization - 1))) >>
               predictor_quantitization;
-        val += buffer_out[0] + error_val;
+        val += buffer_out[i - predictor_coef_num] + error_val;
 
-        buffer_out[predictor_coef_num + 1] = sign_extend(val, readsamplesize);
+        buffer_out[i + 1] = sign_extend(val, readsamplesize);
 
         /* adapt LPC coefficients */
         error_sign = sign_only(error_val);
         if (error_sign) {
             for (j = predictor_coef_num - 1; j >= 0 && error_val * error_sign > 0; j--) {
                 int sign;
-                val  = buffer_out[0] - buffer_out[predictor_coef_num - j];
+                val  = buffer_out[i - predictor_coef_num] - buffer_out[i - j];
                 sign = sign_only(val) * error_sign;
                 predictor_coef_table[j] -= sign;
                 val *= sign;
@@ -232,8 +232,6 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
                               (predictor_coef_num - j));
             }
         }
-
-        buffer_out++;
     }
 }
 

From ebd4c3add1ecad2c65ac80f0787ca5c1e78b600e Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 12:57:16 -0400
Subject: [PATCH 22/38] alac: factor out loading of next decoded sample in LPC
 prediction

---
 libavcodec/alac.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index ba30bef7ea..42dfdad595 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -207,15 +207,16 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         int val = 0;
         int error_val = error_buffer[i + 1];
         int error_sign;
+        int d = buffer_out[i - predictor_coef_num];
 
         for (j = 0; j < predictor_coef_num; j++) {
-            val += (buffer_out[i - j] - buffer_out[i - predictor_coef_num]) *
+            val += (buffer_out[i - j] - d) *
                    predictor_coef_table[j];
         }
 
         val = (val + (1 << (predictor_quantitization - 1))) >>
               predictor_quantitization;
-        val += buffer_out[i - predictor_coef_num] + error_val;
+        val += d + error_val;
 
         buffer_out[i + 1] = sign_extend(val, readsamplesize);
 
@@ -224,7 +225,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
         if (error_sign) {
             for (j = predictor_coef_num - 1; j >= 0 && error_val * error_sign > 0; j--) {
                 int sign;
-                val  = buffer_out[i - predictor_coef_num] - buffer_out[i - j];
+                val  = d - buffer_out[i - j];
                 sign = sign_only(val) * error_sign;
                 predictor_coef_table[j] -= sign;
                 val *= sign;

From 9a6c528e08c42f43216fed9d6abd9e545db88d13 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:01:32 -0400
Subject: [PATCH 23/38] alac: factor out output_size check in
 predictor_decompress_fir_adapt()

---
 libavcodec/alac.c | 8 +++-----
 1 file changed, 3 insertions(+), 5 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 42dfdad595..474531b83e 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -173,10 +173,10 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     /* first sample always copies */
     *buffer_out = *error_buffer;
 
-    if (!predictor_coef_num) {
-        if (output_size <= 1)
-            return;
+    if (output_size <= 1)
+        return;
 
+    if (!predictor_coef_num) {
         memcpy(&buffer_out[1], &error_buffer[1],
                (output_size - 1) * sizeof(*buffer_out));
         return;
@@ -184,8 +184,6 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
 
     if (predictor_coef_num == 31) {
         /* simple 1st-order prediction */
-        if (output_size <= 1)
-            return;
         for (i = 1; i < output_size; i++) {
             buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
                                         readsamplesize);

From 46043962eaf2a8f29290e9ffc19829fceb53f304 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:05:35 -0400
Subject: [PATCH 24/38] alac: avoid using a double-negative when checking if
 the frame is compressed

---
 libavcodec/alac.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 474531b83e..f803f9accc 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -298,7 +298,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     unsigned int outputsamples;
     int hassize;
     unsigned int readsamplesize;
-    int isnotcompressed;
+    int is_compressed;
     uint8_t interlacing_shift;
     uint8_t interlacing_leftweight;
     int i, ch, ret;
@@ -320,7 +320,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     alac->extra_bits = get_bits(&alac->gb, 2) << 3;
 
     /* whether the frame is compressed */
-    isnotcompressed = get_bits1(&alac->gb);
+    is_compressed = !get_bits1(&alac->gb);
 
     if (hassize) {
         /* now read the number of samples as a 32bit integer */
@@ -350,8 +350,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         return -1;
     }
 
-    if (!isnotcompressed) {
-        /* so it is compressed */
+    if (is_compressed) {
         int16_t predictor_coef_table[MAX_CHANNELS][32];
         int predictor_coef_num[MAX_CHANNELS];
         int prediction_type[MAX_CHANNELS];

From 7a50ec6799b92f0e3681d734aa0769857a16ef87 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:15:35 -0400
Subject: [PATCH 25/38] alac: move the current samples per frame to the
 ALACContext

This will simplify the multi-channel implementation.
---
 libavcodec/alac.c | 45 ++++++++++++++++++++++-----------------------
 1 file changed, 22 insertions(+), 23 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index f803f9accc..9e77f67457 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -75,6 +75,7 @@ typedef struct {
     uint8_t  rice_limit;
 
     int extra_bits;                         /**< number of extra bits beyond 16-bit */
+    int nb_samples;                         /**< number of samples in the current frame */
 } ALACContext;
 
 static inline int decode_scalar(GetBitContext *gb, int k, int readsamplesize)
@@ -295,7 +296,6 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     ALACContext *alac = avctx->priv_data;
 
     int channels;
-    unsigned int outputsamples;
     int hassize;
     unsigned int readsamplesize;
     int is_compressed;
@@ -324,21 +324,18 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
 
     if (hassize) {
         /* now read the number of samples as a 32bit integer */
-        outputsamples = get_bits_long(&alac->gb, 32);
-        if (outputsamples > alac->max_samples_per_frame) {
-            av_log(avctx, AV_LOG_ERROR, "outputsamples %d > %d\n",
-                   outputsamples, alac->max_samples_per_frame);
-            return -1;
+        uint32_t output_samples = get_bits_long(&alac->gb, 32);
+        if (!output_samples || output_samples > alac->max_samples_per_frame) {
+            av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %d\n",
+                   output_samples);
+            return AVERROR_INVALIDDATA;
         }
+        alac->nb_samples = output_samples;
     } else
-        outputsamples = alac->max_samples_per_frame;
+        alac->nb_samples = alac->max_samples_per_frame;
 
     /* get output buffer */
-    if (outputsamples > INT32_MAX) {
-        av_log(avctx, AV_LOG_ERROR, "unsupported block size: %u\n", outputsamples);
-        return AVERROR_INVALIDDATA;
-    }
-    alac->frame.nb_samples = outputsamples;
+    alac->frame.nb_samples = alac->nb_samples;
     if ((ret = avctx->get_buffer(avctx, &alac->frame)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;
@@ -373,7 +370,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         }
 
         if (alac->extra_bits) {
-            for (i = 0; i < outputsamples; i++) {
+            for (i = 0; i < alac->nb_samples; i++) {
                 for (ch = 0; ch < channels; ch++)
                     alac->extra_bits_buffer[ch][i] = get_bits(&alac->gb, alac->extra_bits);
             }
@@ -381,7 +378,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         for (ch = 0; ch < channels; ch++) {
             bastardized_rice_decompress(alac,
                                         alac->predict_error_buffer[ch],
-                                        outputsamples,
+                                        alac->nb_samples,
                                         readsamplesize,
                                         ricemodifier[ch] * alac->rice_history_mult / 4);
 
@@ -396,7 +393,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
                  */
                 predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
                                                alac->predict_error_buffer[ch],
-                                               outputsamples, readsamplesize,
+                                               alac->nb_samples, readsamplesize,
                                                NULL, 31, 0);
             } else if (prediction_type[ch] > 0) {
                 av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
@@ -404,14 +401,14 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
             }
             predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
                                            alac->output_samples_buffer[ch],
-                                           outputsamples, readsamplesize,
+                                           alac->nb_samples, readsamplesize,
                                            predictor_coef_table[ch],
                                            predictor_coef_num[ch],
                                            prediction_quantitization[ch]);
         }
     } else {
         /* not compressed, easy case */
-        for (i = 0; i < outputsamples; i++) {
+        for (i = 0; i < alac->nb_samples; i++) {
             for (ch = 0; ch < channels; ch++) {
                 alac->output_samples_buffer[ch][i] = get_sbits_long(&alac->gb,
                                                                     alac->sample_size);
@@ -425,23 +422,24 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         av_log(avctx, AV_LOG_ERROR, "Error : Wrong End Of Frame\n");
 
     if (channels == 2 && interlacing_leftweight) {
-        decorrelate_stereo(alac->output_samples_buffer, outputsamples,
+        decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
                            interlacing_shift, interlacing_leftweight);
     }
 
     if (alac->extra_bits) {
         append_extra_bits(alac->output_samples_buffer, alac->extra_bits_buffer,
-                          alac->extra_bits, alac->channels, outputsamples);
+                          alac->extra_bits, alac->channels, alac->nb_samples);
     }
 
     switch(alac->sample_size) {
     case 16:
         if (channels == 2) {
             interleave_stereo_16(alac->output_samples_buffer,
-                                 (int16_t *)alac->frame.data[0], outputsamples);
+                                 (int16_t *)alac->frame.data[0],
+                                 alac->nb_samples);
         } else {
             int16_t *outbuffer = (int16_t *)alac->frame.data[0];
-            for (i = 0; i < outputsamples; i++) {
+            for (i = 0; i < alac->nb_samples; i++) {
                 outbuffer[i] = alac->output_samples_buffer[0][i];
             }
         }
@@ -449,10 +447,11 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     case 24:
         if (channels == 2) {
             interleave_stereo_24(alac->output_samples_buffer,
-                                 (int32_t *)alac->frame.data[0], outputsamples);
+                                 (int32_t *)alac->frame.data[0],
+                                 alac->nb_samples);
         } else {
             int32_t *outbuffer = (int32_t *)alac->frame.data[0];
-            for (i = 0; i < outputsamples; i++)
+            for (i = 0; i < alac->nb_samples; i++)
                 outbuffer[i] = alac->output_samples_buffer[0][i] << 8;
         }
         break;

From 1193d3feddc1ce9ea233632679630b377d2a9894 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:19:10 -0400
Subject: [PATCH 26/38] alac: use get_sbits() to read LPC coefficients instead
 of casting

---
 libavcodec/alac.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 9e77f67457..db83796963 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -366,7 +366,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
 
             /* read the predictor table */
             for (i = 0; i < predictor_coef_num[ch]; i++)
-                predictor_coef_table[ch][i] = (int16_t)get_bits(&alac->gb, 16);
+                predictor_coef_table[ch][i] = get_sbits(&alac->gb, 16);
         }
 
         if (alac->extra_bits) {

From 7a206eb32f624171a35235f714d44ee9dec9abcb Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:23:22 -0400
Subject: [PATCH 27/38] alac: fix check for valid max_samples_per_frame

---
 libavcodec/alac.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index db83796963..1fc4dc5cec 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -511,9 +511,9 @@ static int alac_set_info(ALACContext *alac)
     bytestream2_skipu(&gb, 12); // size:4, alac:4, version:4
 
     alac->max_samples_per_frame = bytestream2_get_be32u(&gb);
-    if (alac->max_samples_per_frame >= UINT_MAX/4){
-        av_log(alac->avctx, AV_LOG_ERROR,
-               "max_samples_per_frame too large\n");
+    if (!alac->max_samples_per_frame || alac->max_samples_per_frame > INT_MAX) {
+        av_log(alac->avctx, AV_LOG_ERROR, "max samples per frame invalid: %u\n",
+               alac->max_samples_per_frame);
         return AVERROR_INVALIDDATA;
     }
     bytestream2_skipu(&gb, 1);  // compatible version

From 5138ff143f2ab3ea0dd7a34e03820f15ec64451d Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 13:30:03 -0400
Subject: [PATCH 28/38] alac: use AVPacket fields directly in
 alac_decode_frame()

---
 libavcodec/alac.c | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 1fc4dc5cec..ac51c2f3ee 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -291,8 +291,6 @@ static void interleave_stereo_24(int32_t *buffer[MAX_CHANNELS],
 static int alac_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_frame_ptr, AVPacket *avpkt)
 {
-    const uint8_t *inbuffer = avpkt->data;
-    int input_buffer_size = avpkt->size;
     ALACContext *alac = avctx->priv_data;
 
     int channels;
@@ -303,7 +301,7 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     uint8_t interlacing_leftweight;
     int i, ch, ret;
 
-    init_get_bits(&alac->gb, inbuffer, input_buffer_size * 8);
+    init_get_bits(&alac->gb, avpkt->data, avpkt->size * 8);
 
     channels = get_bits(&alac->gb, 3) + 1;
     if (channels != avctx->channels) {
@@ -457,13 +455,14 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         break;
     }
 
-    if (input_buffer_size * 8 - get_bits_count(&alac->gb) > 8)
-        av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n", input_buffer_size * 8 - get_bits_count(&alac->gb));
+    if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8)
+        av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
+               avpkt->size * 8 - get_bits_count(&alac->gb));
 
     *got_frame_ptr   = 1;
     *(AVFrame *)data = alac->frame;
 
-    return input_buffer_size;
+    return avpkt->size;
 }
 
 static av_cold int alac_decode_close(AVCodecContext *avctx)

From 6cda74c155a10bec7321d8c0c5be6fd3d809f41b Mon Sep 17 00:00:00 2001
From: Andrew D'Addesio <modchipv12@gmail.com>
Date: Mon, 9 Jul 2012 14:34:41 -0400
Subject: [PATCH 29/38] alac: simplify channel interleaving

Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
---
 libavcodec/alac.c | 57 ++++++++++++-----------------------------------
 1 file changed, 14 insertions(+), 43 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index ac51c2f3ee..df3c3148eb 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -266,28 +266,6 @@ static void append_extra_bits(int32_t *buffer[MAX_CHANNELS],
             buffer[ch][i] = (buffer[ch][i] << extra_bits) | extra_bits_buffer[ch][i];
 }
 
-static void interleave_stereo_16(int32_t *buffer[MAX_CHANNELS],
-                                 int16_t *buffer_out, int numsamples)
-{
-    int i;
-
-    for (i = 0; i < numsamples; i++) {
-        *buffer_out++ = buffer[0][i];
-        *buffer_out++ = buffer[1][i];
-    }
-}
-
-static void interleave_stereo_24(int32_t *buffer[MAX_CHANNELS],
-                                 int32_t *buffer_out, int numsamples)
-{
-    int i;
-
-    for (i = 0; i < numsamples; i++) {
-        *buffer_out++ = buffer[0][i] << 8;
-        *buffer_out++ = buffer[1][i] << 8;
-    }
-}
-
 static int alac_decode_frame(AVCodecContext *avctx, void *data,
                              int *got_frame_ptr, AVPacket *avpkt)
 {
@@ -430,28 +408,21 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     }
 
     switch(alac->sample_size) {
-    case 16:
-        if (channels == 2) {
-            interleave_stereo_16(alac->output_samples_buffer,
-                                 (int16_t *)alac->frame.data[0],
-                                 alac->nb_samples);
-        } else {
-            int16_t *outbuffer = (int16_t *)alac->frame.data[0];
-            for (i = 0; i < alac->nb_samples; i++) {
-                outbuffer[i] = alac->output_samples_buffer[0][i];
-            }
-        }
+    case 16: {
+        int16_t *outbuffer = (int16_t *)alac->frame.data[0];
+        for (i = 0; i < alac->nb_samples; i++) {
+            *outbuffer++ = alac->output_samples_buffer[0][i];
+            if (channels == 2)
+                *outbuffer++ = alac->output_samples_buffer[1][i];
+        }}
         break;
-    case 24:
-        if (channels == 2) {
-            interleave_stereo_24(alac->output_samples_buffer,
-                                 (int32_t *)alac->frame.data[0],
-                                 alac->nb_samples);
-        } else {
-            int32_t *outbuffer = (int32_t *)alac->frame.data[0];
-            for (i = 0; i < alac->nb_samples; i++)
-                outbuffer[i] = alac->output_samples_buffer[0][i] << 8;
-        }
+    case 24: {
+        int32_t *outbuffer = (int32_t *)alac->frame.data[0];
+        for (i = 0; i < alac->nb_samples; i++) {
+            *outbuffer++ = alac->output_samples_buffer[0][i] << 8;
+            if (channels == 2)
+                *outbuffer++ = alac->output_samples_buffer[1][i] << 8;
+        }}
         break;
     }
 

From 6482bd8831904ab7cd0a126687f871ff9c52b055 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 14:36:03 -0400
Subject: [PATCH 30/38] alac: add 32-bit decoding support

---
 libavcodec/alac.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index df3c3148eb..268d592325 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -424,6 +424,18 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
                 *outbuffer++ = alac->output_samples_buffer[1][i] << 8;
         }}
         break;
+    case 32:
+        if (channels == 2) {
+            int32_t *outbuffer = (int32_t *)alac->frame.data[0];
+            for (i = 0; i < alac->nb_samples; i++) {
+                *outbuffer++ = alac->output_samples_buffer[0][i];
+                *outbuffer++ = alac->output_samples_buffer[1][i];
+            }
+        } else {
+            memcpy(alac->frame.data[0], alac->output_samples_buffer[0],
+                   alac->nb_samples * sizeof(*alac->output_samples_buffer[0]));
+        }
+        break;
     }
 
     if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8)
@@ -520,7 +532,8 @@ static av_cold int alac_decode_init(AVCodecContext * avctx)
     switch (alac->sample_size) {
     case 16: avctx->sample_fmt    = AV_SAMPLE_FMT_S16;
              break;
-    case 24: avctx->sample_fmt    = AV_SAMPLE_FMT_S32;
+    case 24:
+    case 32: avctx->sample_fmt    = AV_SAMPLE_FMT_S32;
              break;
     default: av_log_ask_for_sample(avctx, "Sample depth %d is not supported.\n",
                                    alac->sample_size);

From 73dc0db486b826e1442ae4e4177b4e3724b06a4e Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 15:18:51 -0400
Subject: [PATCH 31/38] alac: output in planar sample format

Avoids unneeded interleaving and allows for reusing the AVFrame output buffer
as the internal buffer for 24-bit and 32-bit sample size.
---
 libavcodec/alac.c | 46 +++++++++++++++++++---------------------------
 1 file changed, 19 insertions(+), 27 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 268d592325..5f2c8a0492 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -316,6 +316,10 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
         return ret;
     }
+    if (alac->sample_size > 16) {
+        for (ch = 0; ch < alac->channels; ch++)
+            alac->output_samples_buffer[ch] = (int32_t *)alac->frame.data[ch];
+    }
 
     readsamplesize = alac->sample_size - alac->extra_bits + channels - 1;
     if (readsamplesize > MIN_CACHE_BITS) {
@@ -409,33 +413,18 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
 
     switch(alac->sample_size) {
     case 16: {
-        int16_t *outbuffer = (int16_t *)alac->frame.data[0];
-        for (i = 0; i < alac->nb_samples; i++) {
-            *outbuffer++ = alac->output_samples_buffer[0][i];
-            if (channels == 2)
-                *outbuffer++ = alac->output_samples_buffer[1][i];
+        for (ch = 0; ch < alac->channels; ch++) {
+            int16_t *outbuffer = (int16_t *)alac->frame.data[ch];
+            for (i = 0; i < alac->nb_samples; i++)
+                *outbuffer++ = alac->output_samples_buffer[ch][i];
         }}
         break;
     case 24: {
-        int32_t *outbuffer = (int32_t *)alac->frame.data[0];
-        for (i = 0; i < alac->nb_samples; i++) {
-            *outbuffer++ = alac->output_samples_buffer[0][i] << 8;
-            if (channels == 2)
-                *outbuffer++ = alac->output_samples_buffer[1][i] << 8;
+        for (ch = 0; ch < alac->channels; ch++) {
+            for (i = 0; i < alac->nb_samples; i++)
+                alac->output_samples_buffer[ch][i] <<= 8;
         }}
         break;
-    case 32:
-        if (channels == 2) {
-            int32_t *outbuffer = (int32_t *)alac->frame.data[0];
-            for (i = 0; i < alac->nb_samples; i++) {
-                *outbuffer++ = alac->output_samples_buffer[0][i];
-                *outbuffer++ = alac->output_samples_buffer[1][i];
-            }
-        } else {
-            memcpy(alac->frame.data[0], alac->output_samples_buffer[0],
-                   alac->nb_samples * sizeof(*alac->output_samples_buffer[0]));
-        }
-        break;
     }
 
     if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8)
@@ -455,7 +444,8 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
     int ch;
     for (ch = 0; ch < alac->channels; ch++) {
         av_freep(&alac->predict_error_buffer[ch]);
-        av_freep(&alac->output_samples_buffer[ch]);
+        if (alac->sample_size == 16)
+            av_freep(&alac->output_samples_buffer[ch]);
         av_freep(&alac->extra_bits_buffer[ch]);
     }
 
@@ -471,8 +461,10 @@ static int allocate_buffers(ALACContext *alac)
         FF_ALLOC_OR_GOTO(alac->avctx, alac->predict_error_buffer[ch],
                          buf_size, buf_alloc_fail);
 
-        FF_ALLOC_OR_GOTO(alac->avctx, alac->output_samples_buffer[ch],
-                         buf_size, buf_alloc_fail);
+        if (alac->sample_size == 16) {
+            FF_ALLOC_OR_GOTO(alac->avctx, alac->output_samples_buffer[ch],
+                             buf_size, buf_alloc_fail);
+        }
 
         FF_ALLOC_OR_GOTO(alac->avctx, alac->extra_bits_buffer[ch],
                          buf_size, buf_alloc_fail);
@@ -530,10 +522,10 @@ static av_cold int alac_decode_init(AVCodecContext * avctx)
     }
 
     switch (alac->sample_size) {
-    case 16: avctx->sample_fmt    = AV_SAMPLE_FMT_S16;
+    case 16: avctx->sample_fmt = AV_SAMPLE_FMT_S16P;
              break;
     case 24:
-    case 32: avctx->sample_fmt    = AV_SAMPLE_FMT_S32;
+    case 32: avctx->sample_fmt = AV_SAMPLE_FMT_S32P;
              break;
     default: av_log_ask_for_sample(avctx, "Sample depth %d is not supported.\n",
                                    alac->sample_size);

From cd632619d954c653add4b4f1820e7d3488a5c9a7 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 15:38:58 -0400
Subject: [PATCH 32/38] alac: support a read sample size of up to 32

Use get_bits_long() in decode_scalar().
Use unsigned int for decoded value.
---
 libavcodec/alac.c | 21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 5f2c8a0492..b44b5c44ba 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -78,13 +78,14 @@ typedef struct {
     int nb_samples;                         /**< number of samples in the current frame */
 } ALACContext;
 
-static inline int decode_scalar(GetBitContext *gb, int k, int readsamplesize)
+static inline unsigned int decode_scalar(GetBitContext *gb, int k,
+                                         int readsamplesize)
 {
-    int x = get_unary_0_9(gb);
+    unsigned int x = get_unary_0_9(gb);
 
     if (x > 8) { /* RICE THRESHOLD */
         /* use alternative encoding */
-        x = get_bits(gb, readsamplesize);
+        x = get_bits_long(gb, readsamplesize);
     } else if (k != 1) {
         int extrabits = show_bits(gb, k);
 
@@ -111,7 +112,8 @@ static void bastardized_rice_decompress(ALACContext *alac,
     int sign_modifier = 0;
 
     for (output_count = 0; output_count < output_size; output_count++) {
-        int x, k;
+        int k;
+        unsigned int x;
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
@@ -294,6 +296,11 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     hassize = get_bits1(&alac->gb);
 
     alac->extra_bits = get_bits(&alac->gb, 2) << 3;
+    readsamplesize = alac->sample_size - alac->extra_bits + channels - 1;
+    if (readsamplesize > 32) {
+        av_log(avctx, AV_LOG_ERROR, "bps is unsupported: %d\n", readsamplesize);
+        return AVERROR_PATCHWELCOME;
+    }
 
     /* whether the frame is compressed */
     is_compressed = !get_bits1(&alac->gb);
@@ -321,12 +328,6 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
             alac->output_samples_buffer[ch] = (int32_t *)alac->frame.data[ch];
     }
 
-    readsamplesize = alac->sample_size - alac->extra_bits + channels - 1;
-    if (readsamplesize > MIN_CACHE_BITS) {
-        av_log(avctx, AV_LOG_ERROR, "readsamplesize too big (%d)\n", readsamplesize);
-        return -1;
-    }
-
     if (is_compressed) {
         int16_t predictor_coef_table[MAX_CHANNELS][32];
         int predictor_coef_num[MAX_CHANNELS];

From 81c9e2e6d074ccbf94e19c67d38b7b62e7c3f820 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 16:05:53 -0400
Subject: [PATCH 33/38] alac: split element parsing into a separate function

This will make multi-channel implementation simpler.
Based partially on a patch by Andrew D'Addesio <modchipv12@gmail.com>.
---
 libavcodec/alac.c | 121 +++++++++++++++++++++++++++++++---------------
 1 file changed, 81 insertions(+), 40 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index b44b5c44ba..1e37290740 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -78,6 +78,18 @@ typedef struct {
     int nb_samples;                         /**< number of samples in the current frame */
 } ALACContext;
 
+enum RawDataBlockType {
+    /* At the moment, only SCE, CPE, LFE, and END are recognized. */
+    TYPE_SCE,
+    TYPE_CPE,
+    TYPE_CCE,
+    TYPE_LFE,
+    TYPE_DSE,
+    TYPE_PCE,
+    TYPE_FIL,
+    TYPE_END
+};
+
 static inline unsigned int decode_scalar(GetBitContext *gb, int k,
                                          int readsamplesize)
 {
@@ -268,27 +280,18 @@ static void append_extra_bits(int32_t *buffer[MAX_CHANNELS],
             buffer[ch][i] = (buffer[ch][i] << extra_bits) | extra_bits_buffer[ch][i];
 }
 
-static int alac_decode_frame(AVCodecContext *avctx, void *data,
-                             int *got_frame_ptr, AVPacket *avpkt)
+static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
+                          int channels)
 {
     ALACContext *alac = avctx->priv_data;
-
-    int channels;
     int hassize;
     unsigned int readsamplesize;
     int is_compressed;
     uint8_t interlacing_shift;
     uint8_t interlacing_leftweight;
+    uint32_t output_samples;
     int i, ch, ret;
 
-    init_get_bits(&alac->gb, avpkt->data, avpkt->size * 8);
-
-    channels = get_bits(&alac->gb, 3) + 1;
-    if (channels != avctx->channels) {
-        av_log(avctx, AV_LOG_ERROR, "frame header channel count mismatch\n");
-        return AVERROR_INVALIDDATA;
-    }
-
     skip_bits(&alac->gb, 4);  /* element instance tag */
     skip_bits(&alac->gb, 12); /* unused header bits */
 
@@ -305,28 +308,32 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
     /* whether the frame is compressed */
     is_compressed = !get_bits1(&alac->gb);
 
-    if (hassize) {
-        /* now read the number of samples as a 32bit integer */
-        uint32_t output_samples = get_bits_long(&alac->gb, 32);
-        if (!output_samples || output_samples > alac->max_samples_per_frame) {
-            av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %d\n",
-                   output_samples);
-            return AVERROR_INVALIDDATA;
-        }
-        alac->nb_samples = output_samples;
-    } else
-        alac->nb_samples = alac->max_samples_per_frame;
-
-    /* get output buffer */
-    alac->frame.nb_samples = alac->nb_samples;
-    if ((ret = avctx->get_buffer(avctx, &alac->frame)) < 0) {
-        av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
-        return ret;
+    if (hassize)
+        output_samples = get_bits_long(&alac->gb, 32);
+    else
+        output_samples = alac->max_samples_per_frame;
+    if (!output_samples || output_samples > alac->max_samples_per_frame) {
+        av_log(avctx, AV_LOG_ERROR, "invalid samples per frame: %d\n",
+               output_samples);
+        return AVERROR_INVALIDDATA;
     }
-    if (alac->sample_size > 16) {
-        for (ch = 0; ch < alac->channels; ch++)
-            alac->output_samples_buffer[ch] = (int32_t *)alac->frame.data[ch];
+    if (!alac->nb_samples) {
+        /* get output buffer */
+        alac->frame.nb_samples = output_samples;
+        if ((ret = avctx->get_buffer(avctx, &alac->frame)) < 0) {
+            av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
+            return ret;
+        }
+        if (alac->sample_size > 16) {
+            for (ch = 0; ch < channels; ch++)
+                alac->output_samples_buffer[ch] = (int32_t *)alac->frame.data[ch_index + ch];
+        }
+    } else if (output_samples != alac->nb_samples) {
+        av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %u != %d\n",
+               output_samples, alac->nb_samples);
+        return AVERROR_INVALIDDATA;
     }
+    alac->nb_samples = output_samples;
 
     if (is_compressed) {
         int16_t predictor_coef_table[MAX_CHANNELS][32];
@@ -391,16 +398,13 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         /* not compressed, easy case */
         for (i = 0; i < alac->nb_samples; i++) {
             for (ch = 0; ch < channels; ch++) {
-                alac->output_samples_buffer[ch][i] = get_sbits_long(&alac->gb,
-                                                                    alac->sample_size);
+                alac->output_samples_buffer[ch][i] = get_sbits_long(&alac->gb, alac->sample_size);
             }
         }
         alac->extra_bits = 0;
         interlacing_shift = 0;
         interlacing_leftweight = 0;
     }
-    if (get_bits(&alac->gb, 3) != 7)
-        av_log(avctx, AV_LOG_ERROR, "Error : Wrong End Of Frame\n");
 
     if (channels == 2 && interlacing_leftweight) {
         decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
@@ -409,25 +413,62 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
 
     if (alac->extra_bits) {
         append_extra_bits(alac->output_samples_buffer, alac->extra_bits_buffer,
-                          alac->extra_bits, alac->channels, alac->nb_samples);
+                          alac->extra_bits, channels, alac->nb_samples);
     }
 
     switch(alac->sample_size) {
     case 16: {
-        for (ch = 0; ch < alac->channels; ch++) {
-            int16_t *outbuffer = (int16_t *)alac->frame.data[ch];
+        for (ch = 0; ch < channels; ch++) {
+            int16_t *outbuffer = (int16_t *)alac->frame.data[ch_index + ch];
             for (i = 0; i < alac->nb_samples; i++)
                 *outbuffer++ = alac->output_samples_buffer[ch][i];
         }}
         break;
     case 24: {
-        for (ch = 0; ch < alac->channels; ch++) {
+        for (ch = 0; ch < channels; ch++) {
             for (i = 0; i < alac->nb_samples; i++)
                 alac->output_samples_buffer[ch][i] <<= 8;
         }}
         break;
     }
 
+    return 0;
+}
+
+static int alac_decode_frame(AVCodecContext *avctx, void *data,
+                             int *got_frame_ptr, AVPacket *avpkt)
+{
+    ALACContext *alac = avctx->priv_data;
+    enum RawDataBlockType element;
+    int channels;
+    int ch, ret;
+
+    init_get_bits(&alac->gb, avpkt->data, avpkt->size * 8);
+
+    alac->nb_samples = 0;
+    ch = 0;
+    while (get_bits_left(&alac->gb)) {
+        element = get_bits(&alac->gb, 3);
+        if (element == TYPE_END)
+            break;
+        if (element > TYPE_CPE && element != TYPE_LFE) {
+            av_log(avctx, AV_LOG_ERROR, "syntax element unsupported: %d", element);
+            return AVERROR_PATCHWELCOME;
+        }
+
+        channels = (element == TYPE_CPE) ? 2 : 1;
+        if (ch + channels > alac->channels) {
+            av_log(avctx, AV_LOG_ERROR, "invalid element channel count\n");
+            return AVERROR_INVALIDDATA;
+        }
+
+        ret = decode_element(avctx, data, ch, channels);
+        if (ret < 0)
+            return ret;
+
+        ch += channels;
+    }
+
     if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8)
         av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
                avpkt->size * 8 - get_bits_count(&alac->gb));

From 1b3ef155d7033fcca4286d6e34a6c15214cb8bb0 Mon Sep 17 00:00:00 2001
From: Andrew D'Addesio <modchipv12@gmail.com>
Date: Mon, 9 Jul 2012 16:29:49 -0400
Subject: [PATCH 34/38] alac: multi-channel decoding support

Signed-off-by: Justin Ruggles <justin.ruggles@gmail.com>
---
 libavcodec/alac.c | 61 +++++++++++++++++++++++++++++++++--------------
 1 file changed, 43 insertions(+), 18 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 1e37290740..8c8e83076f 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -45,7 +45,7 @@
  * 32bit  samplerate
  */
 
-
+#include "libavutil/audioconvert.h"
 #include "avcodec.h"
 #include "get_bits.h"
 #include "bytestream.h"
@@ -53,7 +53,7 @@
 #include "mathops.h"
 
 #define ALAC_EXTRADATA_SIZE 36
-#define MAX_CHANNELS 2
+#define MAX_CHANNELS 8
 
 typedef struct {
 
@@ -64,9 +64,9 @@ typedef struct {
     int channels;
 
     /* buffers */
-    int32_t *predict_error_buffer[MAX_CHANNELS];
-    int32_t *output_samples_buffer[MAX_CHANNELS];
-    int32_t *extra_bits_buffer[MAX_CHANNELS];
+    int32_t *predict_error_buffer[2];
+    int32_t *output_samples_buffer[2];
+    int32_t *extra_bits_buffer[2];
 
     uint32_t max_samples_per_frame;
     uint8_t  sample_size;
@@ -90,6 +90,28 @@ enum RawDataBlockType {
     TYPE_END
 };
 
+static const uint8_t alac_channel_layout_offsets[8][8] = {
+    { 0 },
+    { 0, 1 },
+    { 2, 0, 1 },
+    { 2, 0, 1, 3 },
+    { 2, 0, 1, 3, 4 },
+    { 2, 0, 1, 4, 5, 3 },
+    { 2, 0, 1, 4, 5, 6, 3 },
+    { 2, 6, 7, 0, 1, 4, 5, 3 }
+};
+
+static const uint16_t alac_channel_layouts[8] = {
+    AV_CH_LAYOUT_MONO,
+    AV_CH_LAYOUT_STEREO,
+    AV_CH_LAYOUT_SURROUND,
+    AV_CH_LAYOUT_4POINT0,
+    AV_CH_LAYOUT_5POINT0_BACK,
+    AV_CH_LAYOUT_5POINT1_BACK,
+    AV_CH_LAYOUT_6POINT1_BACK,
+    AV_CH_LAYOUT_7POINT1_WIDE_BACK
+};
+
 static inline unsigned int decode_scalar(GetBitContext *gb, int k,
                                          int readsamplesize)
 {
@@ -249,7 +271,7 @@ static void predictor_decompress_fir_adapt(int32_t *error_buffer,
     }
 }
 
-static void decorrelate_stereo(int32_t *buffer[MAX_CHANNELS],
+static void decorrelate_stereo(int32_t *buffer[2],
                                int numsamples, uint8_t interlacing_shift,
                                uint8_t interlacing_leftweight)
 {
@@ -269,8 +291,8 @@ static void decorrelate_stereo(int32_t *buffer[MAX_CHANNELS],
     }
 }
 
-static void append_extra_bits(int32_t *buffer[MAX_CHANNELS],
-                              int32_t *extra_bits_buffer[MAX_CHANNELS],
+static void append_extra_bits(int32_t *buffer[2],
+                              int32_t *extra_bits_buffer[2],
                               int extra_bits, int numchannels, int numsamples)
 {
     int i, ch;
@@ -326,7 +348,7 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
         }
         if (alac->sample_size > 16) {
             for (ch = 0; ch < channels; ch++)
-                alac->output_samples_buffer[ch] = (int32_t *)alac->frame.data[ch_index + ch];
+                alac->output_samples_buffer[ch] = (int32_t *)alac->frame.extended_data[ch_index + ch];
         }
     } else if (output_samples != alac->nb_samples) {
         av_log(avctx, AV_LOG_ERROR, "sample count mismatch: %u != %d\n",
@@ -336,11 +358,11 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
     alac->nb_samples = output_samples;
 
     if (is_compressed) {
-        int16_t predictor_coef_table[MAX_CHANNELS][32];
-        int predictor_coef_num[MAX_CHANNELS];
-        int prediction_type[MAX_CHANNELS];
-        int prediction_quantitization[MAX_CHANNELS];
-        int ricemodifier[MAX_CHANNELS];
+        int16_t predictor_coef_table[2][32];
+        int predictor_coef_num[2];
+        int prediction_type[2];
+        int prediction_quantitization[2];
+        int ricemodifier[2];
 
         interlacing_shift = get_bits(&alac->gb, 8);
         interlacing_leftweight = get_bits(&alac->gb, 8);
@@ -419,7 +441,7 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
     switch(alac->sample_size) {
     case 16: {
         for (ch = 0; ch < channels; ch++) {
-            int16_t *outbuffer = (int16_t *)alac->frame.data[ch_index + ch];
+            int16_t *outbuffer = (int16_t *)alac->frame.extended_data[ch_index + ch];
             for (i = 0; i < alac->nb_samples; i++)
                 *outbuffer++ = alac->output_samples_buffer[ch][i];
         }}
@@ -462,7 +484,9 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
             return AVERROR_INVALIDDATA;
         }
 
-        ret = decode_element(avctx, data, ch, channels);
+        ret = decode_element(avctx, data,
+                             alac_channel_layout_offsets[alac->channels - 1][ch],
+                             channels);
         if (ret < 0)
             return ret;
 
@@ -484,7 +508,7 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
     ALACContext *alac = avctx->priv_data;
 
     int ch;
-    for (ch = 0; ch < alac->channels; ch++) {
+    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
         av_freep(&alac->predict_error_buffer[ch]);
         if (alac->sample_size == 16)
             av_freep(&alac->output_samples_buffer[ch]);
@@ -497,7 +521,7 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
 static int allocate_buffers(ALACContext *alac)
 {
     int ch;
-    for (ch = 0; ch < alac->channels; ch++) {
+    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
         int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
 
         FF_ALLOC_OR_GOTO(alac->avctx, alac->predict_error_buffer[ch],
@@ -588,6 +612,7 @@ static av_cold int alac_decode_init(AVCodecContext * avctx)
                avctx->channels);
         return AVERROR_PATCHWELCOME;
     }
+    avctx->channel_layout = alac_channel_layouts[alac->channels - 1];
 
     if ((ret = allocate_buffers(alac)) < 0) {
         av_log(avctx, AV_LOG_ERROR, "Error allocating buffers\n");

From 2aebac691827caf78d700cec56b539f4d0d239f6 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 16:52:19 -0400
Subject: [PATCH 35/38] alac: cosmetics: rename some variables and function
 names

---
 libavcodec/alac.c | 170 +++++++++++++++++++++-------------------------
 1 file changed, 77 insertions(+), 93 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 8c8e83076f..1c850986c8 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -112,14 +112,13 @@ static const uint16_t alac_channel_layouts[8] = {
     AV_CH_LAYOUT_7POINT1_WIDE_BACK
 };
 
-static inline unsigned int decode_scalar(GetBitContext *gb, int k,
-                                         int readsamplesize)
+static inline unsigned int decode_scalar(GetBitContext *gb, int k, int bps)
 {
     unsigned int x = get_unary_0_9(gb);
 
     if (x > 8) { /* RICE THRESHOLD */
         /* use alternative encoding */
-        x = get_bits_long(gb, readsamplesize);
+        x = get_bits_long(gb, bps);
     } else if (k != 1) {
         int extrabits = show_bits(gb, k);
 
@@ -135,28 +134,25 @@ static inline unsigned int decode_scalar(GetBitContext *gb, int k,
     return x;
 }
 
-static void bastardized_rice_decompress(ALACContext *alac,
-                                        int32_t *output_buffer,
-                                        int output_size,
-                                        int readsamplesize,
-                                        int rice_history_mult)
+static void rice_decompress(ALACContext *alac, int32_t *output_buffer,
+                            int nb_samples, int bps, int rice_history_mult)
 {
-    int output_count;
+    int i;
     unsigned int history = alac->rice_initial_history;
     int sign_modifier = 0;
 
-    for (output_count = 0; output_count < output_size; output_count++) {
+    for (i = 0; i < nb_samples; i++) {
         int k;
         unsigned int x;
 
         /* read k, that is bits as is */
         k = av_log2((history >> 9) + 3);
         k = FFMIN(k, alac->rice_limit);
-        x = decode_scalar(&alac->gb, k, readsamplesize);
+        x = decode_scalar(&alac->gb, k, bps);
         x += sign_modifier;
         sign_modifier = 0;
 
-        output_buffer[output_count] = (x >> 1) ^ -(x & 1);
+        output_buffer[i] = (x >> 1) ^ -(x & 1);
 
         /* now update the history */
         if (x > 0xffff)
@@ -166,7 +162,7 @@ static void bastardized_rice_decompress(ALACContext *alac,
                        ((history * rice_history_mult) >> 9);
 
         /* special case: there may be compressed blocks of 0 */
-        if ((history < 128) && (output_count+1 < output_size)) {
+        if ((history < 128) && (i + 1 < nb_samples)) {
             int block_size;
 
             k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
@@ -175,13 +171,15 @@ static void bastardized_rice_decompress(ALACContext *alac,
             block_size = decode_scalar(&alac->gb, k, 16);
 
             if (block_size > 0) {
-                if(block_size >= output_size - output_count){
-                    av_log(alac->avctx, AV_LOG_ERROR, "invalid zero block size of %d %d %d\n", block_size, output_size, output_count);
-                    block_size= output_size - output_count - 1;
+                if (block_size >= nb_samples - i) {
+                    av_log(alac->avctx, AV_LOG_ERROR,
+                           "invalid zero block size of %d %d %d\n", block_size,
+                           nb_samples, i);
+                    block_size = nb_samples - i - 1;
                 }
-                memset(&output_buffer[output_count + 1], 0,
+                memset(&output_buffer[i + 1], 0,
                        block_size * sizeof(*output_buffer));
-                output_count += block_size;
+                i += block_size;
             }
 
             if (block_size <= 0xffff)
@@ -197,93 +195,86 @@ static inline int sign_only(int v)
     return v ? FFSIGN(v) : 0;
 }
 
-static void predictor_decompress_fir_adapt(int32_t *error_buffer,
-                                           int32_t *buffer_out,
-                                           int output_size,
-                                           int readsamplesize,
-                                           int16_t *predictor_coef_table,
-                                           int predictor_coef_num,
-                                           int predictor_quantitization)
+static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
+                           int nb_samples, int bps, int16_t *lpc_coefs,
+                           int lpc_order, int lpc_quant)
 {
     int i;
 
     /* first sample always copies */
     *buffer_out = *error_buffer;
 
-    if (output_size <= 1)
+    if (nb_samples <= 1)
         return;
 
-    if (!predictor_coef_num) {
+    if (!lpc_order) {
         memcpy(&buffer_out[1], &error_buffer[1],
-               (output_size - 1) * sizeof(*buffer_out));
+               (nb_samples - 1) * sizeof(*buffer_out));
         return;
     }
 
-    if (predictor_coef_num == 31) {
+    if (lpc_order == 31) {
         /* simple 1st-order prediction */
-        for (i = 1; i < output_size; i++) {
+        for (i = 1; i < nb_samples; i++) {
             buffer_out[i] = sign_extend(buffer_out[i - 1] + error_buffer[i],
-                                        readsamplesize);
+                                        bps);
         }
         return;
     }
 
     /* read warm-up samples */
-    for (i = 0; i < predictor_coef_num; i++) {
+    for (i = 0; i < lpc_order; i++) {
         buffer_out[i + 1] = sign_extend(buffer_out[i] + error_buffer[i + 1],
-                                        readsamplesize);
+                                        bps);
     }
 
     /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
     /* general case */
-    for (i = predictor_coef_num; i < output_size - 1; i++) {
+    for (i = lpc_order; i < nb_samples - 1; i++) {
         int j;
         int val = 0;
         int error_val = error_buffer[i + 1];
         int error_sign;
-        int d = buffer_out[i - predictor_coef_num];
+        int d = buffer_out[i - lpc_order];
 
-        for (j = 0; j < predictor_coef_num; j++) {
-            val += (buffer_out[i - j] - d) *
-                   predictor_coef_table[j];
+        for (j = 0; j < lpc_order; j++) {
+            val += (buffer_out[i - j] - d) * lpc_coefs[j];
         }
 
-        val = (val + (1 << (predictor_quantitization - 1))) >>
-              predictor_quantitization;
+        val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;
         val += d + error_val;
 
-        buffer_out[i + 1] = sign_extend(val, readsamplesize);
+        buffer_out[i + 1] = sign_extend(val, bps);
 
         /* adapt LPC coefficients */
         error_sign = sign_only(error_val);
         if (error_sign) {
-            for (j = predictor_coef_num - 1; j >= 0 && error_val * error_sign > 0; j--) {
+            for (j = lpc_order - 1; j >= 0 && error_val * error_sign > 0; j--) {
                 int sign;
                 val  = d - buffer_out[i - j];
                 sign = sign_only(val) * error_sign;
-                predictor_coef_table[j] -= sign;
+                lpc_coefs[j] -= sign;
                 val *= sign;
-                error_val -= ((val >> predictor_quantitization) *
-                              (predictor_coef_num - j));
+                error_val -= (val >> lpc_quant) * (lpc_order - j);
             }
         }
     }
 }
 
 static void decorrelate_stereo(int32_t *buffer[2],
-                               int numsamples, uint8_t interlacing_shift,
-                               uint8_t interlacing_leftweight)
+                               int nb_samples, uint8_t decorr_shift,
+                               uint8_t decorr_left_weight)
 {
     int i;
 
-    for (i = 0; i < numsamples; i++) {
+    for (i = 0; i < nb_samples; i++) {
         int32_t a, b;
 
         a = buffer[0][i];
         b = buffer[1][i];
 
-        a -= (b * interlacing_leftweight) >> interlacing_shift;
+        a -= (b * decorr_left_weight) >> decorr_shift;
         b += a;
 
         buffer[0][i] = b;
@@ -293,12 +284,12 @@ static void decorrelate_stereo(int32_t *buffer[2],
 
 static void append_extra_bits(int32_t *buffer[2],
                               int32_t *extra_bits_buffer[2],
-                              int extra_bits, int numchannels, int numsamples)
+                              int extra_bits, int channels, int nb_samples)
 {
     int i, ch;
 
-    for (ch = 0; ch < numchannels; ch++)
-        for (i = 0; i < numsamples; i++)
+    for (ch = 0; ch < channels; ch++)
+        for (i = 0; i < nb_samples; i++)
             buffer[ch][i] = (buffer[ch][i] << extra_bits) | extra_bits_buffer[ch][i];
 }
 
@@ -306,11 +297,11 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
                           int channels)
 {
     ALACContext *alac = avctx->priv_data;
-    int hassize;
-    unsigned int readsamplesize;
+    int has_size;
+    unsigned int bps;
     int is_compressed;
-    uint8_t interlacing_shift;
-    uint8_t interlacing_leftweight;
+    uint8_t decorr_shift;
+    uint8_t decorr_left_weight;
     uint32_t output_samples;
     int i, ch, ret;
 
@@ -318,19 +309,19 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
     skip_bits(&alac->gb, 12); /* unused header bits */
 
     /* the number of output samples is stored in the frame */
-    hassize = get_bits1(&alac->gb);
+    has_size = get_bits1(&alac->gb);
 
     alac->extra_bits = get_bits(&alac->gb, 2) << 3;
-    readsamplesize = alac->sample_size - alac->extra_bits + channels - 1;
-    if (readsamplesize > 32) {
-        av_log(avctx, AV_LOG_ERROR, "bps is unsupported: %d\n", readsamplesize);
+    bps = alac->sample_size - alac->extra_bits + channels - 1;
+    if (bps > 32) {
+        av_log(avctx, AV_LOG_ERROR, "bps is unsupported: %d\n", bps);
         return AVERROR_PATCHWELCOME;
     }
 
     /* whether the frame is compressed */
     is_compressed = !get_bits1(&alac->gb);
 
-    if (hassize)
+    if (has_size)
         output_samples = get_bits_long(&alac->gb, 32);
     else
         output_samples = alac->max_samples_per_frame;
@@ -358,25 +349,24 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
     alac->nb_samples = output_samples;
 
     if (is_compressed) {
-        int16_t predictor_coef_table[2][32];
-        int predictor_coef_num[2];
+        int16_t lpc_coefs[2][32];
+        int lpc_order[2];
         int prediction_type[2];
-        int prediction_quantitization[2];
-        int ricemodifier[2];
+        int lpc_quant[2];
+        int rice_history_mult[2];
 
-        interlacing_shift = get_bits(&alac->gb, 8);
-        interlacing_leftweight = get_bits(&alac->gb, 8);
+        decorr_shift       = get_bits(&alac->gb, 8);
+        decorr_left_weight = get_bits(&alac->gb, 8);
 
         for (ch = 0; ch < channels; ch++) {
-            prediction_type[ch] = get_bits(&alac->gb, 4);
-            prediction_quantitization[ch] = get_bits(&alac->gb, 4);
-
-            ricemodifier[ch] = get_bits(&alac->gb, 3);
-            predictor_coef_num[ch] = get_bits(&alac->gb, 5);
+            prediction_type[ch]   = get_bits(&alac->gb, 4);
+            lpc_quant[ch]         = get_bits(&alac->gb, 4);
+            rice_history_mult[ch] = get_bits(&alac->gb, 3);
+            lpc_order[ch]         = get_bits(&alac->gb, 5);
 
             /* read the predictor table */
-            for (i = 0; i < predictor_coef_num[ch]; i++)
-                predictor_coef_table[ch][i] = get_sbits(&alac->gb, 16);
+            for (i = 0; i < lpc_order[ch]; i++)
+                lpc_coefs[ch][i] = get_sbits(&alac->gb, 16);
         }
 
         if (alac->extra_bits) {
@@ -386,11 +376,9 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
             }
         }
         for (ch = 0; ch < channels; ch++) {
-            bastardized_rice_decompress(alac,
-                                        alac->predict_error_buffer[ch],
-                                        alac->nb_samples,
-                                        readsamplesize,
-                                        ricemodifier[ch] * alac->rice_history_mult / 4);
+            rice_decompress(alac, alac->predict_error_buffer[ch],
+                            alac->nb_samples, bps,
+                            rice_history_mult[ch] * alac->rice_history_mult / 4);
 
             /* adaptive FIR filter */
             if (prediction_type[ch] == 15) {
@@ -401,20 +389,16 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
                  * However, this prediction type is not currently used by the
                  * reference encoder.
                  */
-                predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
-                                               alac->predict_error_buffer[ch],
-                                               alac->nb_samples, readsamplesize,
-                                               NULL, 31, 0);
+                lpc_prediction(alac->predict_error_buffer[ch],
+                               alac->predict_error_buffer[ch],
+                               alac->nb_samples, bps, NULL, 31, 0);
             } else if (prediction_type[ch] > 0) {
                 av_log(avctx, AV_LOG_WARNING, "unknown prediction type: %i\n",
                        prediction_type[ch]);
             }
-            predictor_decompress_fir_adapt(alac->predict_error_buffer[ch],
-                                           alac->output_samples_buffer[ch],
-                                           alac->nb_samples, readsamplesize,
-                                           predictor_coef_table[ch],
-                                           predictor_coef_num[ch],
-                                           prediction_quantitization[ch]);
+            lpc_prediction(alac->predict_error_buffer[ch],
+                           alac->output_samples_buffer[ch], alac->nb_samples,
+                           bps, lpc_coefs[ch], lpc_order[ch], lpc_quant[ch]);
         }
     } else {
         /* not compressed, easy case */
@@ -424,13 +408,13 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
             }
         }
         alac->extra_bits = 0;
-        interlacing_shift = 0;
-        interlacing_leftweight = 0;
+        decorr_shift       = 0;
+        decorr_left_weight = 0;
     }
 
-    if (channels == 2 && interlacing_leftweight) {
+    if (channels == 2 && decorr_left_weight) {
         decorrelate_stereo(alac->output_samples_buffer, alac->nb_samples,
-                           interlacing_shift, interlacing_leftweight);
+                           decorr_shift, decorr_left_weight);
     }
 
     if (alac->extra_bits) {

From bae83f2c746f770f92ab4761f4c7bf38ed5045c5 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 16:56:34 -0400
Subject: [PATCH 36/38] alac: change some data types to plain int

---
 libavcodec/alac.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 1c850986c8..7732f17bcf 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -263,8 +263,8 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
 }
 
 static void decorrelate_stereo(int32_t *buffer[2],
-                               int nb_samples, uint8_t decorr_shift,
-                               uint8_t decorr_left_weight)
+                               int nb_samples, int decorr_shift,
+                               int decorr_left_weight)
 {
     int i;
 
@@ -298,10 +298,10 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
 {
     ALACContext *alac = avctx->priv_data;
     int has_size;
-    unsigned int bps;
+    int bps;
     int is_compressed;
-    uint8_t decorr_shift;
-    uint8_t decorr_left_weight;
+    int decorr_shift;
+    int decorr_left_weight;
     uint32_t output_samples;
     int i, ch, ret;
 

From f3e5a7844bbf13620ca4b6a5e19aa087c9141b15 Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 16:57:22 -0400
Subject: [PATCH 37/38] alac: calculate buffer size outside the loop in
 allocate_buffers()

---
 libavcodec/alac.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 7732f17bcf..7c76c62dfe 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -505,9 +505,9 @@ static av_cold int alac_decode_close(AVCodecContext *avctx)
 static int allocate_buffers(ALACContext *alac)
 {
     int ch;
-    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
-        int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
+    int buf_size = alac->max_samples_per_frame * sizeof(int32_t);
 
+    for (ch = 0; ch < FFMIN(alac->channels, 2); ch++) {
         FF_ALLOC_OR_GOTO(alac->avctx, alac->predict_error_buffer[ch],
                          buf_size, buf_alloc_fail);
 

From eeb55f5f2f48dba3cb4530e9c65999471affe26e Mon Sep 17 00:00:00 2001
From: Justin Ruggles <justin.ruggles@gmail.com>
Date: Mon, 9 Jul 2012 17:02:42 -0400
Subject: [PATCH 38/38] alac: cosmetics: general pretty-printing and comment
 clean up

---
 libavcodec/alac.c | 49 +++++++++++++++++------------------------------
 1 file changed, 18 insertions(+), 31 deletions(-)

diff --git a/libavcodec/alac.c b/libavcodec/alac.c
index 7c76c62dfe..310a1f0d5b 100644
--- a/libavcodec/alac.c
+++ b/libavcodec/alac.c
@@ -56,14 +56,11 @@
 #define MAX_CHANNELS 8
 
 typedef struct {
-
     AVCodecContext *avctx;
     AVFrame frame;
     GetBitContext gb;
-
     int channels;
 
-    /* buffers */
     int32_t *predict_error_buffer[2];
     int32_t *output_samples_buffer[2];
     int32_t *extra_bits_buffer[2];
@@ -74,8 +71,8 @@ typedef struct {
     uint8_t  rice_initial_history;
     uint8_t  rice_limit;
 
-    int extra_bits;                         /**< number of extra bits beyond 16-bit */
-    int nb_samples;                         /**< number of samples in the current frame */
+    int extra_bits;     /**< number of extra bits beyond 16-bit */
+    int nb_samples;     /**< number of samples in the current frame */
 } ALACContext;
 
 enum RawDataBlockType {
@@ -145,16 +142,15 @@ static void rice_decompress(ALACContext *alac, int32_t *output_buffer,
         int k;
         unsigned int x;
 
-        /* read k, that is bits as is */
+        /* calculate rice param and decode next value */
         k = av_log2((history >> 9) + 3);
         k = FFMIN(k, alac->rice_limit);
         x = decode_scalar(&alac->gb, k, bps);
         x += sign_modifier;
         sign_modifier = 0;
-
         output_buffer[i] = (x >> 1) ^ -(x & 1);
 
-        /* now update the history */
+        /* update the history */
         if (x > 0xffff)
             history = 0xffff;
         else
@@ -165,9 +161,9 @@ static void rice_decompress(ALACContext *alac, int32_t *output_buffer,
         if ((history < 128) && (i + 1 < nb_samples)) {
             int block_size;
 
-            k = 7 - av_log2(history) + ((history + 16) >> 6 /* / 64 */);
+            /* calculate rice param and decode block size */
+            k = 7 - av_log2(history) + ((history + 16) >> 6);
             k = FFMIN(k, alac->rice_limit);
-
             block_size = decode_scalar(&alac->gb, k, 16);
 
             if (block_size > 0) {
@@ -181,10 +177,8 @@ static void rice_decompress(ALACContext *alac, int32_t *output_buffer,
                        block_size * sizeof(*output_buffer));
                 i += block_size;
             }
-
             if (block_size <= 0xffff)
                 sign_modifier = 1;
-
             history = 0;
         }
     }
@@ -230,7 +224,6 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
 
     /* NOTE: 4 and 8 are very common cases that could be optimized. */
 
-    /* general case */
     for (i = lpc_order; i < nb_samples - 1; i++) {
         int j;
         int val = 0;
@@ -238,13 +231,11 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
         int error_sign;
         int d = buffer_out[i - lpc_order];
 
-        for (j = 0; j < lpc_order; j++) {
+        /* LPC prediction */
+        for (j = 0; j < lpc_order; j++)
             val += (buffer_out[i - j] - d) * lpc_coefs[j];
-        }
-
         val = (val + (1 << (lpc_quant - 1))) >> lpc_quant;
         val += d + error_val;
-
         buffer_out[i + 1] = sign_extend(val, bps);
 
         /* adapt LPC coefficients */
@@ -262,9 +253,8 @@ static void lpc_prediction(int32_t *error_buffer, int32_t *buffer_out,
     }
 }
 
-static void decorrelate_stereo(int32_t *buffer[2],
-                               int nb_samples, int decorr_shift,
-                               int decorr_left_weight)
+static void decorrelate_stereo(int32_t *buffer[2], int nb_samples,
+                               int decorr_shift, int decorr_left_weight)
 {
     int i;
 
@@ -282,8 +272,7 @@ static void decorrelate_stereo(int32_t *buffer[2],
     }
 }
 
-static void append_extra_bits(int32_t *buffer[2],
-                              int32_t *extra_bits_buffer[2],
+static void append_extra_bits(int32_t *buffer[2], int32_t *extra_bits_buffer[2],
                               int extra_bits, int channels, int nb_samples)
 {
     int i, ch;
@@ -297,13 +286,9 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
                           int channels)
 {
     ALACContext *alac = avctx->priv_data;
-    int has_size;
-    int bps;
-    int is_compressed;
-    int decorr_shift;
-    int decorr_left_weight;
+    int has_size, bps, is_compressed, decorr_shift, decorr_left_weight, ret;
     uint32_t output_samples;
-    int i, ch, ret;
+    int i, ch;
 
     skip_bits(&alac->gb, 4);  /* element instance tag */
     skip_bits(&alac->gb, 12); /* unused header bits */
@@ -404,10 +389,11 @@ static int decode_element(AVCodecContext *avctx, void *data, int ch_index,
         /* not compressed, easy case */
         for (i = 0; i < alac->nb_samples; i++) {
             for (ch = 0; ch < channels; ch++) {
-                alac->output_samples_buffer[ch][i] = get_sbits_long(&alac->gb, alac->sample_size);
+                alac->output_samples_buffer[ch][i] =
+                         get_sbits_long(&alac->gb, alac->sample_size);
             }
         }
-        alac->extra_bits = 0;
+        alac->extra_bits   = 0;
         decorr_shift       = 0;
         decorr_left_weight = 0;
     }
@@ -477,9 +463,10 @@ static int alac_decode_frame(AVCodecContext *avctx, void *data,
         ch += channels;
     }
 
-    if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8)
+    if (avpkt->size * 8 - get_bits_count(&alac->gb) > 8) {
         av_log(avctx, AV_LOG_ERROR, "Error : %d bits left\n",
                avpkt->size * 8 - get_bits_count(&alac->gb));
+    }
 
     *got_frame_ptr   = 1;
     *(AVFrame *)data = alac->frame;