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使用FFmpeg以高帧率录制来自网络摄像头的视频

ffmpegvideo-capture
24

我有一款网络摄像头（罗技的Brio 4K流版），能够在Ubuntu 16.04上使用guvcview以1280x720的分辨率和60fps的帧速率录制视频。我使用一个名为“原始相机输入”的视频编解码器。这很好地工作，结果是所需分辨率下的60fps视频。

然而，我需要使用命令行而不是GUI进行录制。guvcview GUI在我的计算机上崩溃了（出现了分段错误，其他用户之前也报告过这个问题），因此我想改用ffmpeg。

不幸的是，当我在终端中使用以下命令时：

ffmpeg -i /dev/video1 -framerate 60 -video_size 1280x720 out.mkv

我的帧速率只有30 fps。当然，这不是由于摄像头本身（在guvcview中它以60 fps工作），但我不明白为什么当我明确要求60 fps时却只能得到30 fps。在ffmpeg的输出中也显示它以30 fps录制：

Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv422p, 1280x720, q=-1--1, 30 fps, 1k tbn, 30 tbc

有什么建议可以使用ffmpeg解决这个问题并以60 fps记录视频吗？

注意：我也尝试了类似以下的方法，但结果仍然只有30 fps：

ffmpeg -f video4linux2 -i /dev/video1 -framerate 60.0 -video_size 1280x720 out.mkv

编辑 1 感谢评论中提供的帮助：参数的顺序很重要。现在正在使用：

ffmpeg -framerate 60 -video_size 1280x720 -i /dev/video1 out.mkv

我仍然能获得大约30帧每秒的速度，并且收到了一个新的（可能更易理解的）警告信息：

[video4linux2,v4l2 @ 0x1ddc4e0] The driver changed the time per frame from 1/60 to 1/30
Input #0, video4linux2,v4l2, from '/dev/video1':
  Duration: N/A, start: 256338.694616, bitrate: 442368 kb/s
    Stream #0:0: Video: rawvideo (YUY2 / 0x32595559), yuyv422, 1280x720, 442368 kb/s, 30 fps, 30 tbr, 1000k tbn, 1000k tbc

我发现有几个关于这个问题的条目 (video4linux2 + The driver changed the time per frame)，但没有清晰的解决方案。

编辑 2 + 3:

v4l2-ctl -d 1 --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
    Index       : 0
    Type        : Video Capture
    Pixel Format: 'YUYV'
    Name        : YUYV 4:2:2
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 160x120
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 176x144
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 320x180
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 320x240
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 352x288
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 340x340
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 424x240
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 440x440
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 480x270
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 640x360
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 800x448
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 800x600
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 848x480
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 960x540
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1024x576
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1280x720
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1600x896
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1920x1080
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)

    Index       : 1
    Type        : Video Capture
    Pixel Format: 'MJPG' (compressed)
    Name        : Motion-JPEG
        Size: Discrete 640x480
            Interval: Discrete 0.008s (120.000 fps)
            Interval: Discrete 0.011s (90.000 fps)
            Interval: Discrete 0.017s (60.000 fps)
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 160x120
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 176x144
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 320x180
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 320x240
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 352x288
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 424x240
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 480x270
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 640x360
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 800x448
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 800x600
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 848x480
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 960x540
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1024x576
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1280x720
            Interval: Discrete 0.011s (90.000 fps)
            Interval: Discrete 0.017s (60.000 fps)
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1600x896
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1920x1080
            Interval: Discrete 0.017s (60.000 fps)
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 2560x1440
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 3840x2160
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 4096x2160
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)

    Index       : 2
    Type        : Video Capture
    Pixel Format: 'NV12'
    Name        : Y/CbCr 4:2:0
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 640x360
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1280x720
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1920x1080
            Interval: Discrete 0.033s (30.000 fps)
            Interval: Discrete 0.042s (24.000 fps)
            Interval: Discrete 0.050s (20.000 fps)
            Interval: Discrete 0.067s (15.000 fps)
            Interval: Discrete 0.100s (10.000 fps)
            Interval: Discrete 0.133s (7.500 fps)
            Interval: Discrete 0.200s (5.000 fps)

编辑 4:

看起来仍然存在使用以下内容的问题：

ffmpeg -f v4l2 -framerate 60 -video_size 1280x720 -input_format mjpeg -i /dev/video1 out.mkv

由于ffmpeg的输出看起来像：

Output #0, matroska, to 'out.mkv':
  Metadata:
  encoder         : Lavf56.40.101
Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuvj422p(pc), 1280x720, q=-1--1, 60 fps, 1k tbn, 60 tbc
  Metadata:
  encoder         : Lavc56.60.100 libx264
Stream mapping:
Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=  198 fps= 37 q=-1.0 Lsize=    1043kB time=00:00:05.38 bitrate=1587.4kbits/s

最后一行所示的 fps（37 而非 60）可靠吗？它在使用 guvcview 时以 60 fps 工作，因此我不认为笔记本电脑写入速度或 CPU 是问题所在。

编辑5：

感谢 @LordNeckbeard 的帮助，现在使用您的额外输出参数命令 ffmpeg -f v4l2 -framerate 60 -video_size 1280x720 -input_format mjpeg -i /dev/video1 -preset faster -pix_fmt yuv420p out.mkv 看起来一切正常：

$ ffmpeg -f v4l2 -framerate 60 -video_size 1280x720 -input_format mjpeg -i /dev/video1 -preset faster -pix_fmt yuv420p out.mkv 
ffmpeg version 2.8.11-0ubuntu0.16.04.1 Copyright (c) 2000-2017 the FFmpeg developers
  built with gcc 5.4.0 (Ubuntu 5.4.0-6ubuntu1~16.04.4) 20160609
  configuration: --prefix=/usr --extra-version=0ubuntu0.16.04.1 --build-suffix=-ffmpeg --toolchain=hardened --libdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --cc=cc --cxx=g++ --enable-gpl --enable-shared --disable-stripping --disable-decoder=libopenjpeg --disable-decoder=libschroedinger --enable-avresample --enable-avisynth --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfontconfig --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx265 --enable-libxvid --enable-libzvbi --enable-openal --enable-opengl --enable-x11grab --enable-libdc1394 --enable-libiec61883 --enable-libzmq --enable-frei0r --enable-libx264 --enable-libopencv
  libavutil      54. 31.100 / 54. 31.100
  libavcodec     56. 60.100 / 56. 60.100
  libavformat    56. 40.101 / 56. 40.101
  libavdevice    56.  4.100 / 56.  4.100
  libavfilter     5. 40.101 /  5. 40.101
  libavresample   2.  1.  0 /  2.  1.  0
  libswscale      3.  1.101 /  3.  1.101
  libswresample   1.  2.101 /  1.  2.101
  libpostproc    53.  3.100 / 53.  3.100
[mjpeg @ 0x1d6f320] Changeing bps to 8
Input #0, video4linux2,v4l2, from '/dev/video1':
  Duration: N/A, start: 259410.922692, bitrate: N/A
    Stream #0:0: Video: mjpeg, yuvj422p(pc, bt470bg/unknown/unknown), 1280x720, -10 kb/s, 60 fps, 60 tbr, 1000k tbn, 1000k tbc
[swscaler @ 0x1d7e480] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 0x1d72620] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 AVX2 LZCNT BMI2
[libx264 @ 0x1d72620] profile High, level 3.2
[libx264 @ 0x1d72620] 264 - core 148 r2643 5c65704 - H.264/MPEG-4 AVC codec - Copyleft 2003-2015 - http://www.videolan.org/x264.html - options: cabac=1 ref=2 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=4 psy=1 psy_rd=1.00:0.00 mixed_ref=0 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=0 threads=6 lookahead_threads=1 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=1 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=20 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, matroska, to 'out.mkv':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: h264 (libx264) (H264 / 0x34363248), yuv420p, 1280x720, q=-1--1, 60 fps, 1k tbn, 60 tbc
    Metadata:
      encoder         : Lavc56.60.100 libx264
Stream mapping:
  Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
frame=  467 fps= 59 q=-1.0 Lsize=     914kB time=00:00:07.83 bitrate= 955.8kbits/s    
video:910kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.434447%
[libx264 @ 0x1d72620] frame I:2     Avg QP:21.96  size: 61186
[libx264 @ 0x1d72620] frame P:118   Avg QP:26.01  size:  4695
[libx264 @ 0x1d72620] frame B:347   Avg QP:27.54  size:   734
[libx264 @ 0x1d72620] consecutive B-frames:  0.4%  1.3%  0.6% 97.6%
[libx264 @ 0x1d72620] mb I  I16..4: 14.7% 45.2% 40.0%
[libx264 @ 0x1d72620] mb P  I16..4:  1.4%  3.7%  0.0%  P16..4: 29.9%  4.1%  0.5%  0.0%  0.0%    skip:60.4%
[libx264 @ 0x1d72620] mb B  I16..4:  0.2%  0.4%  0.0%  B16..8:  5.4%  0.2%  0.0%  direct: 4.3%  skip:89.6%  L0:53.4% L1:42.7% BI: 3.9%
[libx264 @ 0x1d72620] 8x8 transform intra:66.4% inter:71.8%
[libx264 @ 0x1d72620] coded y,uvDC,uvAC intra: 38.1% 50.7% 12.7% inter: 2.8% 7.6% 0.1%
[libx264 @ 0x1d72620] i16 v,h,dc,p: 36% 36% 16% 11%
[libx264 @ 0x1d72620] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 16% 32% 37%  2%  2%  2%  4%  1%  5%
[libx264 @ 0x1d72620] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 18% 46%  8%  2%  3%  3%  4%  3% 12%
[libx264 @ 0x1d72620] i8c dc,h,v,p: 56% 26% 16%  3%
[libx264 @ 0x1d72620] Weighted P-Frames: Y:9.3% UV:7.6%
[libx264 @ 0x1d72620] ref P L0: 58.6% 41.4%
[libx264 @ 0x1d72620] ref B L0: 56.9% 43.1%
[libx264 @ 0x1d72620] ref B L1: 85.5% 14.5%
[libx264 @ 0x1d72620] kb/s:946.85
2
选项的位置很重要。把-framerate 60 -video_size 1280x720放在-i之前，这样它就适用于输入而不是输出了。 - llogan
谢谢！现在我仍然只能获得大约30帧每秒，但是出现了一个新的警告信息：输入＃0，video4linux2，v4l2，来自'/dev/video1'： Duration：N / A，start：256338.694616，bitrate：442368 kb / s Stream＃0：0：Video：rawvideo（YUY2 / 0x32595559），yuyv422，1280x720，442368 kb / s，30 fps，30 tbr，1000k tbn，1000k tbc``` 有什么想法如何解决这个问题？ - Zorglub29
请显示v4l2-ctl --list-formats-ext的输出。 - llogan
请查看主贴（字符数量有限）。 - Zorglub29
摄像头在您提供的输出中没有显示60 fps，尽管产品规格表明应该支持。您是否展示了v4l2-ctl命令的完整输出？此系统上是否有多个摄像头（例如笔记本电脑上方的监视器）？ - llogan
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1个回答
31

必须选择适当的格式

该相机使用其MJPEG编码器可提供高达90fps的帧率，但使用原始视频最多只能提供30fps，因此您必须使用-input_format输入选项告诉它你需要哪种格式：

ffmpeg -f v4l2 -framerate 90 -video_size 1280x720 -input_format mjpeg -i /dev/video1 out.mkv

如果您的计算机无法实时编码，请先进行流复制，然后在闲暇时间以所需格式重新编码：

流复制它，然后稍后以您想要的格式重新编码：

ffmpeg -f v4l2 -framerate 90 -video_size 1280x720 -input_format mjpeg -i /dev/video1 -c copy mjpeg.mkv

然后类似这样：

ffmpeg -i mjpeg.mkv -c:v libx264 -crf 23 -preset medium -pix_fmt yuv420p out.mkv

另请参见:

谢谢！可能还有一些问题：元数据： 编码器：Lavf56.40.101 流#0:0：视频：h264（libx264）（H264 / 0x34363248），yuvj422p（pc），1280x720，q=-1--1，60 fps，1k tbn，60 tbc 元数据： 编码器：Lavc56.60.100 libx264按[q]停止，[?]获取帮助 帧= 1038 fps= 42 q=-1.0 Lsize= 4083kB time=00:00:23.05 bitrate=1451.2kbits/s - Zorglub29
@Zorglub29 添加 -preset faster -pix_fmt yuv420p 输出选项。至于内联的“代码”格式，请使用单个反引号而不是三个，对于格式化 Q 或 A 文本块，请将其突出显示并按 ctrl+k。 - llogan
感谢您提供的格式化技巧和更新的命令，它非常有效。请查看主帖更新。 - Zorglub29
PS：FYI：现在我知道了，多亏了你，相机应该支持1280x720的90fps，我有点贪心，想要完全享受它 :)。但是我无法在guvcview中获得90fps，看起来我在ffmpeg中最多只能获得65fps。我收到了一个警告消息“过去的持续时间太长”。如果我没错（谷歌已经广为人知），这意味着我在我的笔记本电脑上遇到了某种瓶颈？ - Zorglub29
@Zorglub29 尝试使用流复制，然后稍后再重新编码为所需的输出格式：ffmpeg -f v4l2 -framerate 90 -video_size 1280x720 -input_format mjpeg -i /dev/video1 -c copy mjpeg.mkv 然后类似于 ffmpeg -i mjpeg.mkv -c:v libx264 -crf 23 -preset medium -pix_fmt yuv420p out.mkv 此外，您的 ffmpeg 版本较旧，我建议下载最新版本。 - llogan
非常感谢，这非常有用，如果没有您的帮助，我永远不会找到所有这些。使用流复制以90 fps进行录制可以正常工作。您是否想编辑您的答案以添加此内容，还是我将其作为问题的编辑添加？;) - Zorglub29
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