yading@10: /*
yading@10:  * MPEG4 Video frame extraction
yading@10:  * Copyright (c) 2003 Fabrice Bellard
yading@10:  * Copyright (c) 2003 Michael Niedermayer
yading@10:  *
yading@10:  * This file is part of FFmpeg.
yading@10:  *
yading@10:  * FFmpeg is free software; you can redistribute it and/or
yading@10:  * modify it under the terms of the GNU Lesser General Public
yading@10:  * License as published by the Free Software Foundation; either
yading@10:  * version 2.1 of the License, or (at your option) any later version.
yading@10:  *
yading@10:  * FFmpeg is distributed in the hope that it will be useful,
yading@10:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@10:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@10:  * Lesser General Public License for more details.
yading@10:  *
yading@10:  * You should have received a copy of the GNU Lesser General Public
yading@10:  * License along with FFmpeg; if not, write to the Free Software
yading@10:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@10:  */
yading@10: 
yading@10: #define UNCHECKED_BITSTREAM_READER 1
yading@10: 
yading@10: #include "parser.h"
yading@10: #include "mpegvideo.h"
yading@10: #include "mpeg4video.h"
yading@10: #include "mpeg4video_parser.h"
yading@10: 
yading@10: struct Mp4vParseContext {
yading@10:     ParseContext pc;
yading@10:     struct MpegEncContext enc;
yading@10:     int first_picture;
yading@10: };
yading@10: 
yading@10: int ff_mpeg4_find_frame_end(ParseContext *pc, const uint8_t *buf, int buf_size){
yading@10:     int vop_found, i;
yading@10:     uint32_t state;
yading@10: 
yading@10:     vop_found= pc->frame_start_found;
yading@10:     state= pc->state;
yading@10: 
yading@10:     i=0;
yading@10:     if(!vop_found){
yading@10:         for(i=0; i<buf_size; i++){
yading@10:             state= (state<<8) | buf[i];
yading@10:             if(state == 0x1B6){
yading@10:                 i++;
yading@10:                 vop_found=1;
yading@10:                 break;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10: 
yading@10:     if(vop_found){
yading@10:         /* EOF considered as end of frame */
yading@10:         if (buf_size == 0)
yading@10:             return 0;
yading@10:         for(; i<buf_size; i++){
yading@10:             state= (state<<8) | buf[i];
yading@10:             if((state&0xFFFFFF00) == 0x100){
yading@10:                 pc->frame_start_found=0;
yading@10:                 pc->state=-1;
yading@10:                 return i-3;
yading@10:             }
yading@10:         }
yading@10:     }
yading@10:     pc->frame_start_found= vop_found;
yading@10:     pc->state= state;
yading@10:     return END_NOT_FOUND;
yading@10: }
yading@10: 
yading@10: /* XXX: make it use less memory */
yading@10: static int av_mpeg4_decode_header(AVCodecParserContext *s1,
yading@10:                                   AVCodecContext *avctx,
yading@10:                                   const uint8_t *buf, int buf_size)
yading@10: {
yading@10:     struct Mp4vParseContext *pc = s1->priv_data;
yading@10:     MpegEncContext *s = &pc->enc;
yading@10:     GetBitContext gb1, *gb = &gb1;
yading@10:     int ret;
yading@10: 
yading@10:     s->avctx = avctx;
yading@10:     s->current_picture_ptr = &s->current_picture;
yading@10: 
yading@10:     if (avctx->extradata_size && pc->first_picture){
yading@10:         init_get_bits(gb, avctx->extradata, avctx->extradata_size*8);
yading@10:         ret = ff_mpeg4_decode_picture_header(s, gb);
yading@10:     }
yading@10: 
yading@10:     init_get_bits(gb, buf, 8 * buf_size);
yading@10:     ret = ff_mpeg4_decode_picture_header(s, gb);
yading@10:     if (s->width && (!avctx->width || !avctx->height || !avctx->coded_width || !avctx->coded_height)) {
yading@10:         avcodec_set_dimensions(avctx, s->width, s->height);
yading@10:     }
yading@10:     if((s1->flags & PARSER_FLAG_USE_CODEC_TS) && s->avctx->time_base.den>0 && ret>=0){
yading@10:         av_assert1(s1->pts == AV_NOPTS_VALUE);
yading@10:         av_assert1(s1->dts == AV_NOPTS_VALUE);
yading@10: 
yading@10:         s1->pts = av_rescale_q(s->time, (AVRational){1, s->avctx->time_base.den}, (AVRational){1, 1200000});
yading@10:     }
yading@10: 
yading@10:     s1->pict_type= s->pict_type;
yading@10:     pc->first_picture = 0;
yading@10:     return ret;
yading@10: }
yading@10: 
yading@10: static av_cold int mpeg4video_parse_init(AVCodecParserContext *s)
yading@10: {
yading@10:     struct Mp4vParseContext *pc = s->priv_data;
yading@10: 
yading@10:     ff_mpeg4videodec_static_init();
yading@10: 
yading@10:     pc->first_picture = 1;
yading@10:     pc->enc.quant_precision=5;
yading@10:     pc->enc.slice_context_count = 1;
yading@10:     return 0;
yading@10: }
yading@10: 
yading@10: static int mpeg4video_parse(AVCodecParserContext *s,
yading@10:                            AVCodecContext *avctx,
yading@10:                            const uint8_t **poutbuf, int *poutbuf_size,
yading@10:                            const uint8_t *buf, int buf_size)
yading@10: {
yading@10:     ParseContext *pc = s->priv_data;
yading@10:     int next;
yading@10: 
yading@10:     if(s->flags & PARSER_FLAG_COMPLETE_FRAMES){
yading@10:         next= buf_size;
yading@10:     }else{
yading@10:         next= ff_mpeg4_find_frame_end(pc, buf, buf_size);
yading@10: 
yading@10:         if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
yading@10:             *poutbuf = NULL;
yading@10:             *poutbuf_size = 0;
yading@10:             return buf_size;
yading@10:         }
yading@10:     }
yading@10:     av_mpeg4_decode_header(s, avctx, buf, buf_size);
yading@10: 
yading@10:     *poutbuf = buf;
yading@10:     *poutbuf_size = buf_size;
yading@10:     return next;
yading@10: }
yading@10: 
yading@10: 
yading@10: AVCodecParser ff_mpeg4video_parser = {
yading@10:     .codec_ids      = { AV_CODEC_ID_MPEG4 },
yading@10:     .priv_data_size = sizeof(struct Mp4vParseContext),
yading@10:     .parser_init    = mpeg4video_parse_init,
yading@10:     .parser_parse   = mpeg4video_parse,
yading@10:     .parser_close   = ff_parse_close,
yading@10:     .split          = ff_mpeg4video_split,
yading@10: };