用ffmpeg封装h264流到MP4的问题

kingteng 2010-08-06 10:47:22

大家好，我刚接触视频这方面，很没基础，现在项目需要把从设备获取的实时H264的流封装成MP4格式，我用的是FFMPEG这个库，现在的问题是我们的输入和输出没有被封装的痕迹，我贴一些关键的代码，大家帮忙分析一下谢谢了！！

初始化代码



 av_register_all();

 fmt = guess_format(NULL, outfile, NULL);

 oc = av_alloc_format_context();

 oc->oformat = fmt;

	

 snprintf(oc->filename, sizeof(oc->filename), "%s", outfile);



 video_st = NULL;

 audio_st = NULL;

 

 if (fmt->video_codec != CODEC_ID_NONE) {

        video_st = add_video_stream(oc, fmt->video_codec);

  }



 if (av_set_parameters(oc, NULL) < 0) {

        fprintf(stderr, "Invalid output format parameters\n");

        exit(1);

 }

 

 if (video_st){

        open_video(oc, video_st);

 }



 if (!(fmt->flags & AVFMT_NOFILE)) {

        if (url_fopen(&oc->pb,outfile, URL_WRONLY) < 0) {

            fprintf(stderr, "Could not open '%s'\n", outfile);

            exit(1);

        }

 }



 if(av_write_header(oc) < 0){

		PRINTF("av_write_header failed\n");	

		return -1;

 }



 for(;;) {

        /* compute current audio and video time */

		

        if (audio_st)

            audio_pts = (double)audio_st->pts.val * audio_st->time_base.num / audio_st->time_base.den;

        else

            audio_pts = 0.0;



        if (video_st)

            video_pts = (double)video_st->pts.val * video_st->time_base.num / video_st->time_base.den;

        else

            video_pts = 0.0;



        /* write interleaved audio and video frames */

        if (!video_st || (video_st && audio_st && audio_pts < video_pts)) {

           PRINTF("write_audio_frame\n");// write_audio_frame(oc, audio_st);

        } else {

           	write_video_frame(oc, video_st,fd,&msg,1080,720);

	}

然后主要是在write_video_frame里面

static void write_video_frame(AVFormatContext *oc,AVStream *st,int fd,avs_un_msg_t *msg,\

								int width,int height){

	int out_size,ret;

	AVCodecContext *c;

	AVPacket pkt;

	c = st->codec;



	fill_yuv_image(picture,fd,msg,c->width,c->height);

	if(write(FD1,picture->data[0],msg->extra) > 0)

		PRINTF("write to FD1\n");

	av_init_packet(&pkt);

	

	//pkt.pts = msg->u.d4t[1];

	pkt.flags |= PKT_FLAG_KEY;

	pkt.stream_index = st->index;

	pkt.data = (uint8_t *)picture->data[0];//注意这里，原样输出

	pkt.size = msg->extra;//sizeof(AVPicture);

	

	ret = av_write_frame(oc,&pkt);



	//oc->oformat = oc->oformat->next;

	if(ret != 0){

		fprintf(stderr,"Error while writing video frame\n");	

		exit(1);

	}

	av_free_packet(&pkt);

	//frame_count++;

}

fill_yuv_image函数是把我们接收到的实时数据封装到一个AVPicture结构里



static int fill_yuv_image(AVFrame *pic,int fd,avs_un_msg_t *msg,int width,int height){

	int err;

	

	bzero(extradata,MAX_AVS_UN_MSG_EXTRA);

	err = avs_un_recv_msg(fd,msg);

	err = avs_un_recv_msg_extra(fd,msg,extradata);

	

	if(err > 0){

		printf("recv extradata %d\n",err);

		if(write(FD2,extradata,err) > 0)

			PRINTF("write to FD2\n");

		if(avpicture_fill((AVPicture *)pic,extradata,PIX_FMT_YUV420P,width,height) < 0){

			PRINTF("avpicture_fill failed\n");	

			return -1;

		}

	}else{

		PRINTF("avs_un_recv_msg_extra failed\n");	

		return -1;

	}

	return 0;

}