ffplay流程分析

void main()
{
     is = stream_open(input_filename, file_iformat);
}

static VideoState *stream_open(const char *filename, AVInputFormat *iformat)
{
    is->read_tid     = SDL_CreateThread(read_thread, "read_thread", is);
}

static int read_thread(void *arg)
{
     /* open the streams */
    if (st_index[AVMEDIA_TYPE_AUDIO] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_AUDIO]);
    }

    ret = -1;
    if (st_index[AVMEDIA_TYPE_VIDEO] >= 0) {
        ret = stream_component_open(is, st_index[AVMEDIA_TYPE_VIDEO]);
    }
    if (is->show_mode == SHOW_MODE_NONE)
        is->show_mode = ret >= 0 ? SHOW_MODE_VIDEO : SHOW_MODE_RDFT;

    if (st_index[AVMEDIA_TYPE_SUBTITLE] >= 0) {
        stream_component_open(is, st_index[AVMEDIA_TYPE_SUBTITLE]);
    }
}

static int stream_component_open(VideoState *is, int stream_index)
{
    //audio
     decoder_init(&is->auddec, avctx, &is->audioq, is->continue_read_thread);
        if ((is->ic->iformat->flags & (AVFMT_NOBINSEARCH | AVFMT_NOGENSEARCH | AVFMT_NO_BYTE_SEEK)) && !is->ic->iformat->read_seek) {
            is->auddec.start_pts = is->audio_st->start_time;
            is->auddec.start_pts_tb = is->audio_st->time_base;
        }
        if ((ret = decoder_start(&is->auddec, audio_thread, is)) < 0)
    
    //video
     decoder_init(&is->viddec, avctx, &is->videoq, is->continue_read_thread);
        if ((ret = decoder_start(&is->viddec, video_thread, is)) < 0)

   //subtitle
   decoder_init(&is->subdec, avctx, &is->subtitleq, is->continue_read_thread);
        if ((ret = decoder_start(&is->subdec, subtitle_thread, is)) < 0)
}