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ffmpeg在cheese以每秒20帧的速度记录的设备上每秒记录5帧

video-capture ffmpeg

4

David Parks · 技术社区 · 7 年前

ffmpeg 在我的内置网络摄像头上拍摄:

ffmpeg -f v4l2 -framerate 30 -video_size 1920x1080 -i /dev/video0 output.mkv

我只获得5帧/秒,并看到以下消息:

The driver changed the time per frame from 1/30 to 1/5

当我用奶酪录制时,我在那个设备上得到了20帧/秒的效果。和 v4l2 似乎声称它可以每秒30帧。

v4l2-ctl --list-formats-ext
ioctl: VIDIOC_ENUM_FMT
    Index       : 0
    Type        : Video Capture
    Pixel Format: 'MJPG' (compressed)
    Name        : Motion-JPEG
        Size: Discrete 1920x1080
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 1280x720
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 800x600
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x360
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 160x120
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 320x240
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)

    Index       : 1
    Type        : Video Capture
    Pixel Format: 'YUYV'
    Name        : YUYV 4:2:2
        Size: Discrete 1920x1080
            Interval: Discrete 0.200s (5.000 fps)
        Size: Discrete 1280x720
            Interval: Discrete 0.100s (10.000 fps)
        Size: Discrete 800x600
            Interval: Discrete 0.050s (20.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x360
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 160x120
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 320x240
            Interval: Discrete 0.033s (30.000 fps)
        Size: Discrete 640x480
            Interval: Discrete 0.033s (30.000 fps)

Output #0, mjpeg, to 'output.mjpg':
  Metadata:
    encoder         : Lavf56.40.101
    Stream #0:0: Video: mjpeg, yuvj422p(pc), 1920x1080, q=2-31, 200 kb/s, 5 fps, 5 tbn, 5 tbc
    Metadata:
      encoder         : Lavc56.60.100 mjpeg

我的猜测是,它以原始形式从设备中录制,并以ffmpeg进行编码。如果这是正确的,我将如何让ffmpeg使用mjpeg本机格式?

1 回复 | 直到 7 年前

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David Parks 7 年前

我需要用我的网络摄像头支持的本地压缩运动jpeg格式录制。一旦我得到了配置(见下文),它记录在30 fps的全分辨率。

ffmpeg -f v4l2 -framerate 30 -video_size 1920x1080 -c:v mjpeg -i /dev/video0 -c:v copy output.mov

注意 -c:v -i -c: 五、 (输入)指示录制编解码器ffmpeg应转换为什么。 copy