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Make ff_mlp_read_major_sync() take a GetBitContext instead of buffers.

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Originally committed as revision 14044 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Ramiro Polla 2008-07-01 01:36:16 +00:00
parent 6122c92e92
commit 49de8d1e9c
2 changed files with 29 additions and 29 deletions
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55
libavcodec/mlp_parser.c
View File

@ -88,74 +88,73 @@ static uint16_t mlp_checksum16(const uint8_t *buf, unsigned int buf_size)
/** Read a major sync info header - contains high level information about
* the stream - sample rate, channel arrangement etc. Most of this
* information is not actually necessary for decoding, only for playback.
* gb must be a freshly initialized GetBitContext with no bits read.
*/
int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, const uint8_t *buf,
unsigned int buf_size)
int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb)
{
GetBitContext gb;
int ratebits;
uint16_t checksum;
if (buf_size < 28) {
assert(get_bits_count(gb) == 0);
if (gb->size_in_bits < 28 << 3) {
av_log(log, AV_LOG_ERROR, "Packet too short, unable to read major sync\n");
return -1;
}
checksum = mlp_checksum16(buf, 26);
if (checksum != AV_RL16(buf+26)) {
checksum = mlp_checksum16(gb->buffer, 26);
if (checksum != AV_RL16(gb->buffer+26)) {
av_log(log, AV_LOG_ERROR, "Major sync info header checksum error\n");
return -1;
}
init_get_bits(&gb, buf, buf_size * 8);
if (get_bits_long(&gb, 24) != 0xf8726f) /* Sync words */
if (get_bits_long(gb, 24) != 0xf8726f) /* Sync words */
return -1;
mh->stream_type = get_bits(&gb, 8);
mh->stream_type = get_bits(gb, 8);
if (mh->stream_type == 0xbb) {
mh->group1_bits = mlp_quants[get_bits(&gb, 4)];
mh->group2_bits = mlp_quants[get_bits(&gb, 4)];
mh->group1_bits = mlp_quants[get_bits(gb, 4)];
mh->group2_bits = mlp_quants[get_bits(gb, 4)];
ratebits = get_bits(&gb, 4);
ratebits = get_bits(gb, 4);
mh->group1_samplerate = mlp_samplerate(ratebits);
mh->group2_samplerate = mlp_samplerate(get_bits(&gb, 4));
mh->group2_samplerate = mlp_samplerate(get_bits(gb, 4));
skip_bits(&gb, 11);
skip_bits(gb, 11);
mh->channels_mlp = get_bits(&gb, 5);
mh->channels_mlp = get_bits(gb, 5);
} else if (mh->stream_type == 0xba) {
mh->group1_bits = 24; // TODO: Is this information actually conveyed anywhere?
mh->group2_bits = 0;
ratebits = get_bits(&gb, 4);
ratebits = get_bits(gb, 4);
mh->group1_samplerate = mlp_samplerate(ratebits);
mh->group2_samplerate = 0;
skip_bits(&gb, 8);
skip_bits(gb, 8);
mh->channels_thd_stream1 = get_bits(&gb, 5);
mh->channels_thd_stream1 = get_bits(gb, 5);
skip_bits(&gb, 2);
skip_bits(gb, 2);
mh->channels_thd_stream2 = get_bits(&gb, 13);
mh->channels_thd_stream2 = get_bits(gb, 13);
} else
return -1;
mh->access_unit_size = 40 << (ratebits & 7);
mh->access_unit_size_pow2 = 64 << (ratebits & 7);
skip_bits_long(&gb, 48);
skip_bits_long(gb, 48);
mh->is_vbr = get_bits1(&gb);
mh->is_vbr = get_bits1(gb);
mh->peak_bitrate = (get_bits(&gb, 15) * mh->group1_samplerate + 8) >> 4;
mh->peak_bitrate = (get_bits(gb, 15) * mh->group1_samplerate + 8) >> 4;
mh->num_substreams = get_bits(&gb, 4);
mh->num_substreams = get_bits(gb, 4);
skip_bits_long(&gb, 4 + 11 * 8);
skip_bits_long(gb, 4 + 11 * 8);
return 0;
}
@ -258,9 +257,11 @@ static int mlp_parse(AVCodecParserContext *s,
goto lost_sync;
}
} else {
GetBitContext gb;
MLPHeaderInfo mh;
if (ff_mlp_read_major_sync(avctx, &mh, buf + 4, buf_size - 4) < 0)
init_get_bits(&gb, buf + 4, (buf_size - 4) << 3);
if (ff_mlp_read_major_sync(avctx, &mh, &gb) < 0)
goto lost_sync;
#ifdef CONFIG_AUDIO_NONSHORT

3
libavcodec/mlp_parser.h
View File

@ -53,8 +53,7 @@ typedef struct MLPHeaderInfo
} MLPHeaderInfo;
int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, const uint8_t *buf,
unsigned int buf_size);
int ff_mlp_read_major_sync(void *log, MLPHeaderInfo *mh, GetBitContext *gb);
#endif /* FFMPEG_MLP_PARSER_H */