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mjpeg parser

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Originally committed as revision 3634 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2004-10-24 22:37:29 +00:00
parent b551204a96
commit 8e6325b96b
3 changed files with 74 additions and 0 deletions
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1
libavcodec/allcodecs.c
View File

@ -233,6 +233,7 @@ PCM_CODEC(CODEC_ID_ADPCM_CT, adpcm_ct);
av_register_codec_parser(&h261_parser);
av_register_codec_parser(&h263_parser);
av_register_codec_parser(&h264_parser);
av_register_codec_parser(&mjpeg_parser);
av_register_codec_parser(&mpegaudio_parser);
#ifdef CONFIG_AC3

1
libavcodec/avcodec.h
View File

@ -2161,6 +2161,7 @@ extern AVCodecParser mpeg4video_parser;
extern AVCodecParser h261_parser;
extern AVCodecParser h263_parser;
extern AVCodecParser h264_parser;
extern AVCodecParser mjpeg_parser;
extern AVCodecParser mpegaudio_parser;
extern AVCodecParser ac3_parser;

72
libavcodec/mjpeg.c
View File

@ -896,6 +896,69 @@ static int mjpeg_decode_init(AVCodecContext *avctx)
return 0;
}
/**
* finds the end of the current frame in the bitstream.
* @return the position of the first byte of the next frame, or -1
*/
static int find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
int vop_found, i;
uint16_t state;
vop_found= pc->frame_start_found;
state= pc->state;
i=0;
if(!vop_found){
for(i=0; i<buf_size; i++){
state= (state<<8) | buf[i];
if(state == 0xFFD8){
i++;
vop_found=1;
break;
}
}
}
if(vop_found){
/* EOF considered as end of frame */
if (buf_size == 0)
return 0;
for(; i<buf_size; i++){
state= (state<<8) | buf[i];
if(state == 0xFFD8){
pc->frame_start_found=0;
pc->state=0;
return i-1;
}
}
}
pc->frame_start_found= vop_found;
pc->state= state;
return END_NOT_FOUND;
}
static int jpeg_parse(AVCodecParserContext *s,
AVCodecContext *avctx,
uint8_t **poutbuf, int *poutbuf_size,
const uint8_t *buf, int buf_size)
{
ParseContext *pc = s->priv_data;
int next;
next= find_frame_end(pc, buf, buf_size);
if (ff_combine_frame(pc, next, (uint8_t **)&buf, &buf_size) < 0) {
*poutbuf = NULL;
*poutbuf_size = 0;
return buf_size;
}
*poutbuf = (uint8_t *)buf;
*poutbuf_size = buf_size;
return next;
}
/* quantize tables */
static int mjpeg_decode_dqt(MJpegDecodeContext *s)
{
@ -2224,3 +2287,12 @@ AVCodec ljpeg_encoder = { //FIXME avoid MPV_* lossless jpeg shouldnt need them
MPV_encode_end,
};
#endif
AVCodecParser mjpeg_parser = {
{ CODEC_ID_MJPEG },
sizeof(ParseContext),
NULL,
jpeg_parse,
ff_parse_close,
};