ffmpeg之print_report

正常ffmpeg会输出

frame=   9 fps=0.0 q=-0.0 size=      28kB time=00:00:00.28 bitrate= 814.2kbits/s speed=0.518x  

1. frame= 目前所有的帧数

frame_number = ost->frame_number

2. • fps= 当前帧率

t = (cur_time-timer_start) / 1000000.0; //cur_time:当前时间    timer_start: ffmpeg开启时间
fps = t > 1 ? frame_number / t : 0;

3. q = 视频质量因子

q = ost->quality / (float) FF_QP2LAMBDA;   // packet quality factor(质量因数)

4. size=已经发送的数据大小

   total_size = avio_size(oc->pb);  //avio 获得

5. bitrate=比特率

bitrate = pts && total_size >= 0 ? total_size * 8 / (pts / 1000.0) : -1;

6.speed=输出数据流的pts时间戳和ffmpeg的时间戳的比率

    t = (cur_time-timer_start) / 1000000.0;
    pts = FFMAX(pts, av_rescale_q(av_stream_get_end_pts(ost->st),  //outstream 获取pts
                                          ost->st->time_base, AV_TIME_BASE_Q));
    speed = t != 0.0 ? (double)pts / AV_TIME_BASE / t : -1;