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ffmpeg-mt
Commit 988fbb31 authored by michael's avatar michael
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Rewrite mp3 parser. New code is much simpler and does not drop 

stuff at random.


git-svn-id: file:///var/local/repositories/ffmpeg/trunk@19300 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b
parent 9fc8d0d7
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Showing with 37 additions and 142 deletions
libavcodec/mpegaudio_parser.c
View file @ 988fbb31
...@@ -26,11 +26,8 @@ ...@@ -26,11 +26,8 @@
typedef struct MpegAudioParseContext { typedef struct MpegAudioParseContext {
uint8_t inbuf[MPA_MAX_CODED_FRAME_SIZE]; /* input buffer */ ParseContext pc;
uint8_t *inbuf_ptr;
int frame_size; int frame_size;
int free_format_frame_size;
int free_format_next_header;
uint32_t header; uint32_t header;
int header_count; int header_count;
} MpegAudioParseContext; } MpegAudioParseContext;
...@@ -81,174 +78,72 @@ int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, ...@@ -81,174 +78,72 @@ int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate,
return s->frame_size; return s->frame_size;
} }
static av_cold int mpegaudio_parse_init(AVCodecParserContext *s1)
{
MpegAudioParseContext *s = s1->priv_data;
s->inbuf_ptr = s->inbuf;
return 0;
}
static int mpegaudio_parse(AVCodecParserContext *s1, static int mpegaudio_parse(AVCodecParserContext *s1,
AVCodecContext *avctx, AVCodecContext *avctx,
const uint8_t **poutbuf, int *poutbuf_size, const uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size) const uint8_t *buf, int buf_size)
{ {
MpegAudioParseContext *s = s1->priv_data; MpegAudioParseContext *s = s1->priv_data;
int len, ret, sr, channels, bit_rate, frame_size; ParseContext *pc = &s->pc;
uint32_t header; uint32_t state= pc->state;
const uint8_t *buf_ptr; int i;
int next= END_NOT_FOUND;
*poutbuf = NULL;
*poutbuf_size = 0; for(i=0; i<buf_size; ){
buf_ptr = buf; if(s->frame_size){
while (buf_size > 0) { int inc= FFMIN(buf_size - i, s->frame_size);
len = s->inbuf_ptr - s->inbuf; i += inc;
if (s->frame_size == 0) { s->frame_size -= inc;
/* special case for next header for first frame in free
format case (XXX: find a simpler method) */ if(!s->frame_size){
if (s->free_format_next_header != 0) { next= i;
AV_WB32(s->inbuf, s->free_format_next_header); break;
s->inbuf_ptr = s->inbuf + 4;
s->free_format_next_header = 0;
goto got_header;
} }
/* no header seen : find one. We need at least MPA_HEADER_SIZE }else{
bytes to parse it */ while(i<buf_size){
len = FFMIN(MPA_HEADER_SIZE - len, buf_size); int ret, sr, channels, bit_rate, frame_size;
if (len > 0) {
memcpy(s->inbuf_ptr, buf_ptr, len); state= (state<<8) + buf[i++];
buf_ptr += len;
buf_size -= len;
s->inbuf_ptr += len;
}
if ((s->inbuf_ptr - s->inbuf) >= MPA_HEADER_SIZE) {
got_header:
header = AV_RB32(s->inbuf);
ret = ff_mpa_decode_header(avctx, header, &sr, &channels, &frame_size, &bit_rate); ret = ff_mpa_decode_header(avctx, state, &sr, &channels, &frame_size, &bit_rate);
if (ret < 0) { if (ret < 4) {
s->header_count= -2; s->header_count= -2;
/* no sync found : move by one byte (inefficient, but simple!) */
memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
s->inbuf_ptr--;
dprintf(avctx, "skip %x\n", header);
/* reset free format frame size to give a chance
to get a new bitrate */
s->free_format_frame_size = 0;
} else { } else {
if((header&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header) if((state&SAME_HEADER_MASK) != (s->header&SAME_HEADER_MASK) && s->header)
s->header_count= -3; s->header_count= -3;
s->header= header; s->header= state;
s->header_count++; s->header_count++;
s->frame_size = ret; s->frame_size = ret-4;
#if 0
/* free format: prepare to compute frame size */
if (ff_mpegaudio_decode_header((MPADecodeHeader *)s, header) == 1) {
s->frame_size = -1;
}
#endif
if(s->header_count > 1){ if(s->header_count > 1){
avctx->sample_rate= sr; avctx->sample_rate= sr;
avctx->channels = channels; avctx->channels = channels;
avctx->frame_size = frame_size; avctx->frame_size = frame_size;
avctx->bit_rate = bit_rate; avctx->bit_rate = bit_rate;
} }
break;
} }
} }
} else
#if 0
if (s->frame_size == -1) {
/* free format : find next sync to compute frame size */
len = MPA_MAX_CODED_FRAME_SIZE - len;
if (len > buf_size)
len = buf_size;
if (len == 0) {
/* frame too long: resync */
s->frame_size = 0;
memmove(s->inbuf, s->inbuf + 1, s->inbuf_ptr - s->inbuf - 1);
s->inbuf_ptr--;
} else {
uint8_t *p, *pend;
uint32_t header1;
int padding;
memcpy(s->inbuf_ptr, buf_ptr, len);
/* check for header */
p = s->inbuf_ptr - 3;
pend = s->inbuf_ptr + len - 4;
while (p <= pend) {
header = AV_RB32(p);
header1 = AV_RB32(s->inbuf);
/* check with high probability that we have a
valid header */
if ((header & SAME_HEADER_MASK) ==
(header1 & SAME_HEADER_MASK)) {
/* header found: update pointers */
len = (p + 4) - s->inbuf_ptr;
buf_ptr += len;
buf_size -= len;
s->inbuf_ptr = p;
/* compute frame size */
s->free_format_next_header = header;
s->free_format_frame_size = s->inbuf_ptr - s->inbuf;
padding = (header1 >> 9) & 1;
if (s->layer == 1)
s->free_format_frame_size -= padding * 4;
else
s->free_format_frame_size -= padding;
dprintf(avctx, "free frame size=%d padding=%d\n",
s->free_format_frame_size, padding);
ff_mpegaudio_decode_header((MPADecodeHeader *)s, header1);
goto next_data;
}
p++;
}
/* not found: simply increase pointers */
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
}
} else
#endif
if (len < s->frame_size) {
if (s->frame_size > MPA_MAX_CODED_FRAME_SIZE)
s->frame_size = MPA_MAX_CODED_FRAME_SIZE;
len = FFMIN(s->frame_size - len, buf_size);
memcpy(s->inbuf_ptr, buf_ptr, len);
buf_ptr += len;
s->inbuf_ptr += len;
buf_size -= len;
}
if(s->frame_size > 0 && buf_ptr - buf == s->inbuf_ptr - s->inbuf
&& buf_size + buf_ptr - buf >= s->frame_size){
*poutbuf = buf;
*poutbuf_size = s->frame_size;
buf_ptr = buf + s->frame_size;
s->inbuf_ptr = s->inbuf;
s->frame_size = 0;
break;
} }
}
// next_data: pc->state= state;
if (s->frame_size > 0 && if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
(s->inbuf_ptr - s->inbuf) >= s->frame_size) { *poutbuf = NULL;
*poutbuf = s->inbuf; *poutbuf_size = 0;
*poutbuf_size = s->inbuf_ptr - s->inbuf; return buf_size;
s->inbuf_ptr = s->inbuf;
s->frame_size = 0;
break;
}
} }
return buf_ptr - buf;
*poutbuf = buf;
*poutbuf_size = buf_size;
return next;
} }
AVCodecParser mpegaudio_parser = { AVCodecParser mpegaudio_parser = {
{ CODEC_ID_MP1, CODEC_ID_MP2, CODEC_ID_MP3 }, { CODEC_ID_MP1, CODEC_ID_MP2, CODEC_ID_MP3 },
sizeof(MpegAudioParseContext), sizeof(MpegAudioParseContext),
mpegaudio_parse_init, NULL,
mpegaudio_parse, mpegaudio_parse,
NULL, NULL,
}; };
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