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Add the ability to parse the ALSSpecificConfig from an MPEG-4 AudioSpecificConfig. Patch by Thilo Borgmann

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<com googlemail borgmann thilo> as part of GSoC 2009.

Originally committed as revision 20516 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Thilo Borgmann 2009-11-11 22:16:54 +00:00 committed by Alex Converse
parent ca02d8ec97
commit 24026a2d49
1 changed files with 40 additions and 1 deletions
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41
libavcodec/mpeg4audio.c
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@ -24,6 +24,34 @@
#include "put_bits.h"
#include "mpeg4audio.h"
/**
* Parse MPEG-4 audio configuration for ALS object type.
* @param[in] gb bit reader context
* @param[in] c MPEG4AudioConfig structure to fill
* @return on success 0 is returned, otherwise a value < 0
*/
static int parse_config_ALS(GetBitContext *gb, MPEG4AudioConfig *c)
{
if (gb->size_in_bits - get_bits_count(gb) < 112)
return -1;
if (get_bits_long(gb, 32) != MKBETAG('A','L','S','\0'))
return -1;
// override AudioSpecificConfig channel configuration and sample rate
// which are buggy in old ALS conformance files
c->sample_rate = get_bits_long(gb, 32);
// skip number of samples
skip_bits_long(gb, 32);
// read number of channels
c->chan_config = 0;
c->channels = get_bits(gb, 16) + 1;
return 0;
}
const int ff_mpeg4audio_sample_rates[16] = {
96000, 88200, 64000, 48000, 44100, 32000,
24000, 22050, 16000, 12000, 11025, 8000, 7350
@ -73,8 +101,19 @@ int ff_mpeg4audio_get_config(MPEG4AudioConfig *c, const uint8_t *buf, int buf_si
}
specific_config_bitindex = get_bits_count(&gb);
if (c->object_type == AOT_ALS) {
skip_bits(&gb, 5);
if (show_bits_long(&gb, 24) != MKBETAG('\0','A','L','S'))
skip_bits_long(&gb, 24);
specific_config_bitindex = get_bits_count(&gb);
if (parse_config_ALS(&gb, c))
return -1;
}
if (c->ext_object_type != AOT_SBR) {
int bits_left = buf_size*8 - specific_config_bitindex;
int bits_left = buf_size*8 - get_bits_count(&gb);
for (; bits_left > 15; bits_left--) {
if (show_bits(&gb, 11) == 0x2b7) { // sync extension
get_bits(&gb, 11);