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Move decode_frame_header() from flacdec.c to flac.c/h to share with the

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forthcoming FLAC parser.
Patch by Michael Chinen [mchinen at gmail]

Originally committed as revision 25909 to svn://svn.ffmpeg.org/ffmpeg/trunk
oldabi
Michael Chinen 14 years ago committed by Justin Ruggles
parent 86b6e387cc
commit 625daac4bd
3 changed files with 105 additions and 101 deletions
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  1. 94
      libavcodec/flac.c
  2. 10
      libavcodec/flac.h
  3. 102
      libavcodec/flacdec.c

94
libavcodec/flac.c
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@ -19,7 +19,101 @@
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/ */
#include "libavutil/crc.h"
#include "flac.h" #include "flac.h"
#include "flacdata.h"
static const int8_t sample_size_table[] = { 0, 8, 12, 0, 16, 20, 24, 0 };
static int64_t get_utf8(GetBitContext *gb)
{
int64_t val;
GET_UTF8(val, get_bits(gb, 8), return -1;)
return val;
}
int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
FLACFrameInfo *fi)
{
int bs_code, sr_code, bps_code;
/* frame sync code */
skip_bits(gb, 16);
/* block size and sample rate codes */
bs_code = get_bits(gb, 4);
sr_code = get_bits(gb, 4);
/* channels and decorrelation */
fi->ch_mode = get_bits(gb, 4);
if (fi->ch_mode < FLAC_MAX_CHANNELS) {
fi->channels = fi->ch_mode + 1;
fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
} else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) {
fi->channels = 2;
} else {
av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode);
return -1;
}
/* bits per sample */
bps_code = get_bits(gb, 3);
if (bps_code == 3 || bps_code == 7) {
av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
bps_code);
return -1;
}
fi->bps = sample_size_table[bps_code];
/* reserved bit */
if (get_bits1(gb)) {
av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
return -1;
}
/* sample or frame count */
if (get_utf8(gb) < 0) {
av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n");
return -1;
}
/* blocksize */
if (bs_code == 0) {
av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
return -1;
} else if (bs_code == 6) {
fi->blocksize = get_bits(gb, 8) + 1;
} else if (bs_code == 7) {
fi->blocksize = get_bits(gb, 16) + 1;
} else {
fi->blocksize = ff_flac_blocksize_table[bs_code];
}
/* sample rate */
if (sr_code < 12) {
fi->samplerate = ff_flac_sample_rate_table[sr_code];
} else if (sr_code == 12) {
fi->samplerate = get_bits(gb, 8) * 1000;
} else if (sr_code == 13) {
fi->samplerate = get_bits(gb, 16);
} else if (sr_code == 14) {
fi->samplerate = get_bits(gb, 16) * 10;
} else {
av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
sr_code);
return -1;
}
/* header CRC-8 check */
skip_bits(gb, 8);
if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
get_bits_count(gb)/8)) {
av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n");
return -1;
}
return 0;
}
int ff_flac_get_max_frame_size(int blocksize, int ch, int bps) int ff_flac_get_max_frame_size(int blocksize, int ch, int bps)
{ {

10
libavcodec/flac.h
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@ -28,6 +28,7 @@
#define AVCODEC_FLAC_H #define AVCODEC_FLAC_H
#include "avcodec.h" #include "avcodec.h"
#include "get_bits.h"
#define FLAC_STREAMINFO_SIZE 34 #define FLAC_STREAMINFO_SIZE 34
#define FLAC_MAX_CHANNELS 8 #define FLAC_MAX_CHANNELS 8
@ -120,4 +121,13 @@ void ff_flac_parse_block_header(const uint8_t *block_header,
*/ */
int ff_flac_get_max_frame_size(int blocksize, int ch, int bps); int ff_flac_get_max_frame_size(int blocksize, int ch, int bps);
/**
* Validate and decode a frame header.
* @param avctx AVCodecContext to use as av_log() context
* @param gb GetBitContext from which to read frame header
* @param[out] fi frame information
* @return non-zero on error, 0 if ok
*/
int ff_flac_decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
FLACFrameInfo *fi);
#endif /* AVCODEC_FLAC_H */ #endif /* AVCODEC_FLAC_H */

102
libavcodec/flacdec.c
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@ -67,16 +67,6 @@ typedef struct FLACContext {
unsigned int allocated_bitstream_size; unsigned int allocated_bitstream_size;
} FLACContext; } FLACContext;
static const int sample_size_table[] =
{ 0, 8, 12, 0, 16, 20, 24, 0 };
static int64_t get_utf8(GetBitContext *gb)
{
int64_t val;
GET_UTF8(val, get_bits(gb, 8), return -1;)
return val;
}
static void allocate_buffers(FLACContext *s); static void allocate_buffers(FLACContext *s);
int ff_flac_is_extradata_valid(AVCodecContext *avctx, int ff_flac_is_extradata_valid(AVCodecContext *avctx,
@ -480,103 +470,13 @@ static inline int decode_subframe(FLACContext *s, int channel)
return 0; return 0;
} }
/**
* Validate and decode a frame header.
* @param avctx AVCodecContext to use as av_log() context
* @param gb GetBitContext from which to read frame header
* @param[out] fi frame information
* @return non-zero on error, 0 if ok
*/
static int decode_frame_header(AVCodecContext *avctx, GetBitContext *gb,
FLACFrameInfo *fi)
{
int bs_code, sr_code, bps_code;
/* frame sync code */
skip_bits(gb, 16);
/* block size and sample rate codes */
bs_code = get_bits(gb, 4);
sr_code = get_bits(gb, 4);
/* channels and decorrelation */
fi->ch_mode = get_bits(gb, 4);
if (fi->ch_mode < FLAC_MAX_CHANNELS) {
fi->channels = fi->ch_mode + 1;
fi->ch_mode = FLAC_CHMODE_INDEPENDENT;
} else if (fi->ch_mode <= FLAC_CHMODE_MID_SIDE) {
fi->channels = 2;
} else {
av_log(avctx, AV_LOG_ERROR, "invalid channel mode: %d\n", fi->ch_mode);
return -1;
}
/* bits per sample */
bps_code = get_bits(gb, 3);
if (bps_code == 3 || bps_code == 7) {
av_log(avctx, AV_LOG_ERROR, "invalid sample size code (%d)\n",
bps_code);
return -1;
}
fi->bps = sample_size_table[bps_code];
/* reserved bit */
if (get_bits1(gb)) {
av_log(avctx, AV_LOG_ERROR, "broken stream, invalid padding\n");
return -1;
}
/* sample or frame count */
if (get_utf8(gb) < 0) {
av_log(avctx, AV_LOG_ERROR, "utf8 fscked\n");
return -1;
}
/* blocksize */
if (bs_code == 0) {
av_log(avctx, AV_LOG_ERROR, "reserved blocksize code: 0\n");
return -1;
} else if (bs_code == 6) {
fi->blocksize = get_bits(gb, 8) + 1;
} else if (bs_code == 7) {
fi->blocksize = get_bits(gb, 16) + 1;
} else {
fi->blocksize = ff_flac_blocksize_table[bs_code];
}
/* sample rate */
if (sr_code < 12) {
fi->samplerate = ff_flac_sample_rate_table[sr_code];
} else if (sr_code == 12) {
fi->samplerate = get_bits(gb, 8) * 1000;
} else if (sr_code == 13) {
fi->samplerate = get_bits(gb, 16);
} else if (sr_code == 14) {
fi->samplerate = get_bits(gb, 16) * 10;
} else {
av_log(avctx, AV_LOG_ERROR, "illegal sample rate code %d\n",
sr_code);
return -1;
}
/* header CRC-8 check */
skip_bits(gb, 8);
if (av_crc(av_crc_get_table(AV_CRC_8_ATM), 0, gb->buffer,
get_bits_count(gb)/8)) {
av_log(avctx, AV_LOG_ERROR, "header crc mismatch\n");
return -1;
}
return 0;
}
static int decode_frame(FLACContext *s) static int decode_frame(FLACContext *s)
{ {
int i; int i;
GetBitContext *gb = &s->gb; GetBitContext *gb = &s->gb;
FLACFrameInfo fi; FLACFrameInfo fi;
if (decode_frame_header(s->avctx, gb, &fi)) { if (ff_flac_decode_frame_header(s->avctx, gb, &fi)) {
av_log(s->avctx, AV_LOG_ERROR, "invalid frame header\n"); av_log(s->avctx, AV_LOG_ERROR, "invalid frame header\n");
return -1; return -1;
} }

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