avcodec/dolby_e: Avoid code duplication when converting input

convert_input, a nontrivial auxiliary function used by both the general
parsing code as well as the decoder itself, has been duplicated in
c7016e35a624a75bb5b82bee932ddfe28d013b3f; this commit removes said
duplication.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>

libavcodec/dolby_e.c

@@ -25,7 +25,6 @@
 
 #include "internal.h"
 #include "get_bits.h"
-#include "put_bits.h"
 #include "dolby_e.h"
 #include "kbdwin.h"
 #include "fft.h"
@@ -626,42 +625,6 @@ static int parse_key(DBEContext *s)
     return 0;
 }
 
-static int convert_input(DBEContext *s, int nb_words, int key)
-{
-    const uint8_t *src = s->input;
-    uint8_t *dst = s->buffer;
-    PutBitContext pb;
-    int i;
-
-    av_assert0(nb_words <= 1024u);
-
-    if (nb_words > s->input_size) {
-        av_log(s->avctx, AV_LOG_ERROR, "Packet too short\n");
-        return AVERROR_INVALIDDATA;
-    }
-
-    switch (s->word_bits) {
-    case 16:
-        for (i = 0; i < nb_words; i++, src += 2, dst += 2)
-            AV_WB16(dst, AV_RB16(src) ^ key);
-        break;
-    case 20:
-        init_put_bits(&pb, s->buffer, sizeof(s->buffer));
-        for (i = 0; i < nb_words; i++, src += 3)
-            put_bits(&pb, 20, AV_RB24(src) >> 4 ^ key);
-        flush_put_bits(&pb);
-        break;
-    case 24:
-        for (i = 0; i < nb_words; i++, src += 3, dst += 3)
-            AV_WB24(dst, AV_RB24(src) ^ key);
-        break;
-    default:
-        av_assert0(0);
-    }
-
-    return init_get_bits(&s->gb, s->buffer, nb_words * s->word_bits);
-}
-
 static int parse_metadata_ext(DBEDecodeContext *s1)
 {
     DBEContext *s = &s1->dectx;
@@ -992,7 +955,8 @@ static int parse_audio(DBEDecodeContext *s1, int start, int end, int seg_id)
             s1->channels[seg_id][ch].nb_groups = 0;
             continue;
         }
-        if ((ret = convert_input(s, s->metadata.ch_size[ch], key)) < 0)
+        ret = ff_dolby_e_convert_input(s, s->metadata.ch_size[ch], key);
+        if (ret < 0)
             return ret;
         if ((ret = parse_channel(s1, ch, seg_id)) < 0) {
             if (s1->avctx->err_recognition & AV_EF_EXPLODE)

libavcodec/dolby_e.h

@@ -84,6 +84,13 @@ typedef struct DBEContext {
 static const uint16_t sample_rate_tab[16] = {
     0, 42965, 43008, 44800, 53706, 53760
 };
+
+/**
+ * Use the provided key to transform the input into data (put into s->buffer)
+ * suitable for further processing and initialize s->gb to read said data.
+ */
+int ff_dolby_e_convert_input(DBEContext *s, int nb_words, int key);
+
 /**
  * Initialize DBEContext and parse Dolby E metadata.
  * Set word_bits/word_bytes, input, input_size, key_present

libavcodec/dolby_e_parse.c

@@ -53,7 +53,7 @@ static int parse_key(DBEContext *s)
     return 0;
 }
 
-static int convert_input(DBEContext *s, int nb_words, int key)
+int ff_dolby_e_convert_input(DBEContext *s, int nb_words, int key)
 {
     const uint8_t *src = s->input;
     uint8_t *dst = s->buffer;
@@ -63,6 +63,8 @@ static int convert_input(DBEContext *s, int nb_words, int key)
     av_assert0(nb_words <= 1024u);
 
     if (nb_words > s->input_size) {
+        if (s->avctx)
+            av_log(s->avctx, AV_LOG_ERROR, "Packet too short\n");
         return AVERROR_INVALIDDATA;
     }
 
@@ -116,7 +118,7 @@ int ff_dolby_e_parse_header(DBEContext *s, const uint8_t *buf, int buf_size)
 
     if ((key = parse_key(s)) < 0)
         return key;
-    if ((ret = convert_input(s, 1, key)) < 0)
+    if ((ret = ff_dolby_e_convert_input(s, 1, key)) < 0)
         return ret;
 
     skip_bits(&s->gb, 4);
@@ -127,7 +129,7 @@ int ff_dolby_e_parse_header(DBEContext *s, const uint8_t *buf, int buf_size)
         return AVERROR_INVALIDDATA;
     }
 
-    if ((ret = convert_input(s, mtd_size, key)) < 0)
+    if ((ret = ff_dolby_e_convert_input(s, mtd_size, key)) < 0)
         return ret;
 
     skip_bits(&s->gb, 14);