FFMPEG tbr tbc tbn

libavformat/utils.c

{code}
    if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO){
        if(st->avg_frame_rate.den && st->avg_frame_rate.num)
            print_fps(av_q2d(st->avg_frame_rate), "fps");
#if FF_API_R_FRAME_RATE             
        if(st->r_frame_rate.den && st->r_frame_rate.num)
            print_fps(av_q2d(st->r_frame_rate), "tbr");
#endif
        if(st->time_base.den && st->time_base.num)
            print_fps(1/av_q2d(st->time_base), "tbn");
        if(st->codec->time_base.den && st->codec->time_base.num)
            print_fps(1/av_q2d(st->codec->time_base), "tbc");
    }
{code}

Stream #0:0: Video: h264 (High), yuv420p, 960x540, 1024 kb/s, 24 tbr, 1k tbn, 48 tbc

• tbn = the time base in AVStream that has come from the container

• tbc = the time base in AVCodecContext for the codec used for a particular stream
• tbr = tbr is guessed from the video stream and is the value users want to see when they look for the video frame rate

tbr: 表示帧率，即24
tbn: 表示文件的时间精度， 即1 seconds 等于1k
tbc: 表示视频的时间精度， 即 1 seconds等于48