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native ac3 parser

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Originally committed as revision 4878 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Måns Rullgård 2006-01-21 18:19:47 +00:00
parent 13c7145135
commit 62327e2852
3 changed files with 96 additions and 35 deletions
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7
libavcodec/a52dec.c
View File

@ -76,13 +76,6 @@ static void* dlsymm(void* handle, const char* symbol)
av_log( NULL, AV_LOG_ERROR, "A52 Decoder - function '%s' can't be resolved\n", symbol);
return f;
}
int ff_a52_syncinfo( AVCodecContext * avctx, uint8_t * buf, int * flags, int * sample_rate, int * bit_rate )
{
AC3DecodeState *s = avctx->priv_data;
return s->a52_syncinfo(buf, flags, sample_rate, bit_rate);
}
#endif
static int a52_decode_init(AVCodecContext *avctx)

2
libavcodec/allcodecs.c
View File

@ -614,9 +614,7 @@ PCM_CODEC(CODEC_ID_ADPCM_YAMAHA, adpcm_yamaha);
av_register_codec_parser(&pnm_parser);
av_register_codec_parser(&mpegaudio_parser);
#ifdef CONFIG_AC3
av_register_codec_parser(&ac3_parser);
#endif
#ifdef CONFIG_DVDSUB_DECODER
av_register_codec_parser(&dvdsub_parser);

122
libavcodec/parser.c
View File

@ -748,24 +748,106 @@ static int mpegaudio_parse(AVCodecParserContext *s1,
return buf_ptr - buf;
}
#ifdef CONFIG_AC3
#ifdef CONFIG_A52BIN
extern int ff_a52_syncinfo (AVCodecContext * avctx, const uint8_t * buf,
int * flags, int * sample_rate, int * bit_rate);
#else
extern int a52_syncinfo (const uint8_t * buf, int * flags,
int * sample_rate, int * bit_rate);
#endif
typedef struct AC3ParseContext {
uint8_t inbuf[4096]; /* input buffer */
uint8_t *inbuf_ptr;
int frame_size;
int flags;
} AC3ParseContext;
#define AC3_HEADER_SIZE 7
#define A52_LFE 16
static const int ac3_sample_rates[4] = {
48000, 44100, 32000, 0
};
static const int ac3_frame_sizes[64][3] = {
{ 64, 69, 96 },
{ 64, 70, 96 },
{ 80, 87, 120 },
{ 80, 88, 120 },
{ 96, 104, 144 },
{ 96, 105, 144 },
{ 112, 121, 168 },
{ 112, 122, 168 },
{ 128, 139, 192 },
{ 128, 140, 192 },
{ 160, 174, 240 },
{ 160, 175, 240 },
{ 192, 208, 288 },
{ 192, 209, 288 },
{ 224, 243, 336 },
{ 224, 244, 336 },
{ 256, 278, 384 },
{ 256, 279, 384 },
{ 320, 348, 480 },
{ 320, 349, 480 },
{ 384, 417, 576 },
{ 384, 418, 576 },
{ 448, 487, 672 },
{ 448, 488, 672 },
{ 512, 557, 768 },
{ 512, 558, 768 },
{ 640, 696, 960 },
{ 640, 697, 960 },
{ 768, 835, 1152 },
{ 768, 836, 1152 },
{ 896, 975, 1344 },
{ 896, 976, 1344 },
{ 1024, 1114, 1536 },
{ 1024, 1115, 1536 },
{ 1152, 1253, 1728 },
{ 1152, 1254, 1728 },
{ 1280, 1393, 1920 },
{ 1280, 1394, 1920 },
};
static const int ac3_bitrates[64] = {
32, 32, 40, 40, 48, 48, 56, 56, 64, 64, 80, 80, 96, 96, 112, 112,
128, 128, 160, 160, 192, 192, 224, 224, 256, 256, 320, 320, 384,
384, 448, 448, 512, 512, 576, 576, 640, 640,
};
static const int ac3_channels[8] = {
2, 1, 2, 3, 3, 4, 4, 5
};
static int ac3_sync(const uint8_t *buf, int *channels, int *sample_rate,
int *bit_rate)
{
unsigned int fscod, frmsizecod, acmod, bsid, lfeon;
GetBitContext bits;
init_get_bits(&bits, buf, AC3_HEADER_SIZE * 8);
if(get_bits(&bits, 16) != 0x0b77)
return 0;
get_bits(&bits, 16); /* crc */
fscod = get_bits(&bits, 2);
frmsizecod = get_bits(&bits, 6);
if(!ac3_sample_rates[fscod])
return 0;
bsid = get_bits(&bits, 5);
if(bsid > 8)
return 0;
get_bits(&bits, 3); /* bsmod */
acmod = get_bits(&bits, 3);
if(acmod & 1 && acmod != 1)
get_bits(&bits, 2); /* cmixlev */
if(acmod & 4)
get_bits(&bits, 2); /* surmixlev */
if(acmod & 2)
get_bits(&bits, 2); /* dsurmod */
lfeon = get_bits(&bits, 1);
*sample_rate = ac3_sample_rates[fscod];
*bit_rate = ac3_bitrates[frmsizecod] * 1000;
*channels = ac3_channels[acmod] + lfeon;
return ac3_frame_sizes[frmsizecod][fscod] * 2;
}
static int ac3_parse_init(AVCodecParserContext *s1)
{
@ -781,10 +863,7 @@ static int ac3_parse(AVCodecParserContext *s1,
{
AC3ParseContext *s = s1->priv_data;
const uint8_t *buf_ptr;
int len, sample_rate, bit_rate;
static const int ac3_channels[8] = {
2, 1, 2, 3, 3, 4, 4, 5
};
int len, sample_rate, bit_rate, channels;
*poutbuf = NULL;
*poutbuf_size = 0;
@ -802,11 +881,7 @@ static int ac3_parse(AVCodecParserContext *s1,
s->inbuf_ptr += len;
buf_size -= len;
if ((s->inbuf_ptr - s->inbuf) == AC3_HEADER_SIZE) {
#ifdef CONFIG_A52BIN
len = ff_a52_syncinfo(avctx, s->inbuf, &s->flags, &sample_rate, &bit_rate);
#else
len = a52_syncinfo(s->inbuf, &s->flags, &sample_rate, &bit_rate);
#endif
len = ac3_sync(s->inbuf, &channels, &sample_rate, &bit_rate);
if (len == 0) {
/* no sync found : move by one byte (inefficient, but simple!) */
memmove(s->inbuf, s->inbuf + 1, AC3_HEADER_SIZE - 1);
@ -817,9 +892,7 @@ static int ac3_parse(AVCodecParserContext *s1,
avctx->sample_rate = sample_rate;
/* set channels,except if the user explicitly requests 1 or 2 channels, XXX/FIXME this is a bit ugly */
if(avctx->channels!=1 && avctx->channels!=2){
avctx->channels = ac3_channels[s->flags & 7];
if (s->flags & A52_LFE)
avctx->channels++;
avctx->channels = channels;
}
avctx->bit_rate = bit_rate;
avctx->frame_size = 6 * 256;
@ -844,7 +917,6 @@ static int ac3_parse(AVCodecParserContext *s1,
}
return buf_ptr - buf;
}
#endif
AVCodecParser mpegvideo_parser = {
{ CODEC_ID_MPEG1VIDEO, CODEC_ID_MPEG2VIDEO },
@ -872,7 +944,6 @@ AVCodecParser mpegaudio_parser = {
NULL,
};
#ifdef CONFIG_AC3
AVCodecParser ac3_parser = {
{ CODEC_ID_AC3 },
sizeof(AC3ParseContext),
@ -880,4 +951,3 @@ AVCodecParser ac3_parser = {
ac3_parse,
NULL,
};
#endif