[FFmpeg-user] Can FFmpeg Record Video On Linux Using V4L2 in V4L2_CAP_VIDEO_CAPTURE_MPLANE Mode?

Wed Apr 28 17:36:35 EEST 2021

Hi Moritz,

Thanks for your response. I'm going to try to get the email format right here but if I don't feel free to yell at me and let me know how it is supposed to be.

>> On Wed, Apr 28, 2021 at 13:17:25 +0000, FFmpeg user discussions wrote:
>> $ ffmpeg -f v4l2 -list_formats all -i /dev/video1  # Look at device 
>> information
>>
>> $ ffmpeg -f v4l2 -framerate 25 -video_size 640x480 -i /dev/video0 
>> output.mkv  # save the video

> You'll have to use the same device for both commands, but I assume that's a typo or a copy/paste mistake.

That was a copy paste error it should have been /dev/video0 for both, sorry about that. Just fyi I have 4 video devices video0-video3 that are all the same so I do not believe it should matter. 

>> I get the following output with both commands
>>
>> [video4linux2,v4l2 @ 0xcbbd4f0] Not a video capture device.
>> /dev/video1: No such device

> You should show us the complete, uncut console output of the command using the correct device.

Here is the full output of trying to capture video.

$ ffmpeg -f v4l2 -framerate 25 -video_size 640x480 -i /dev/video0
ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.2.0 (GCC)
  configuration: --disable-stripping --enable-pic --enable-shared --enable-pthreads --cross-prefix=aarch64-klondike-linux- --ld='aarch64-klondike-linux-gcc --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --cc='aarch64-klondike-linux-gcc --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --cxx='aarch64-klondike-linux-g++ --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --arch=aarch64 --target-os=linux --enable-cross-compile --extra-cflags=' -O2 -pipe -g -feliminate-unused-debug-types -fmacro-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0=/usr/src/debug/ffmpeg/4.2.1-r0 -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0=/usr/src/debug/ffmpeg/4.2.1-r0 -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot= -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot-native= --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --extra-ldflags='-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed' --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot --libdir=/usr/lib --shlibdir=/usr/lib --datadir=/usr/share/ffmpeg --disable-mipsdsp --disable-mipsdspr2 --cpu=generic --pkg-config=pkg-config --disable-static --enable-alsa --enable-avcodec --enable-avdevice --enable-avfilter --enable-avformat --enable-avresample --enable-bzlib --enable-gpl --disable-libgsm --disable-indev=jack --disable-libvorbis --enable-lzma --disable-libmfx --disable-libmp3lame --disable-openssl --enable-postproc --disable-sdl2 --disable-libspeex --enable-swresample --enable-swscale --enable-libtheora --disable-vaapi --disable-vdpau --disable-libvpx --enable-libx264 --disable-libxcb --disable-outdev=xv --enable-zlib
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
[video4linux2,v4l2 @ 0x2f506540] Not a video capture device.
/dev/video0: No such device

> Can you also use a tool such as v4l-info, and post its output here?

I don't have v4l-info but I am hoping this is similar to what you wanted.

$ v4l2-ctl --info
Driver Info:
        Driver name      : mxc-isi
        Card type        : mxc-isi
        Bus info         : platform:58100000.isi.0
        Driver version   : 4.14.98
        Capabilities     : 0x84201000
                Video Capture Multiplanar
                Streaming
                Extended Pix Format
                Device Capabilities
        Device Caps      : 0x04201000
                Video Capture Multiplanar
                Streaming
                Extended Pix Format
Media Driver Info:
        Driver name      : mxc-md
        Model            : FSL Capture Media Deivce
        Serial           :
        Bus info         :
        Media version    : 4.14.98
        Hardware revision: 0x00000000 (0)
        Driver version   : 4.14.98
Interface Info:
        ID               : 0x03000014
        Type             : V4L Video
Entity Info:
        ID               : 0x00000012 (18)
        Name             : mxc_isi.0.capture
        Function         : V4L2 I/O
        Pad 0x01000013   : Sink
          Link 0x02000066: from remote pad 0x100000e of entity 'mxc_isi.0': Data, Enabled

>> I see here (https://github.com/FFmpeg/FFmpeg/blob/master/libavdevice/v4l2.c#L172) that v4l2 devices need to support V4L2_CAP_VIDEO_CAPTURE to open. My device does not support V4L2_CAP_VIDEO_CAPTURE but it does support V4L2_CAP_VIDEO_CAPTURE_MPLANE. Does FFmpeg have support for V4L2_CAP_VIDEO_CAPTURE_MPLANE?

> I'm not really too knowledgable about these "newer" devices, but I believe they are supported by the v4l2_m2m codec(s). Someone else may need to explain why your device isn't recognized, after you have provided the requested output.

> Here is a check for MPLANE:
> https://github.com/FFmpeg/FFmpeg/blob/8bc7f69cefbcbb265b41717608dc8436dc864a55/libavcodec/v4l2_m2m.c#L51

I tried using v4l2_m2m as an input format but that was probably wrong. 

$ ffmpeg -f v4l2_m2m -framerate 25 -video_size 640x480 -i /dev/video0
ffmpeg version 4.2.1 Copyright (c) 2000-2019 the FFmpeg developers
  built with gcc 9.2.0 (GCC)
  configuration: --disable-stripping --enable-pic --enable-shared --enable-pthreads --cross-prefix=aarch64-klondike-linux- --ld='aarch64-klondike-linux-gcc --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --cc='aarch64-klondike-linux-gcc --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --cxx='aarch64-klondike-linux-g++ --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --arch=aarch64 --target-os=linux --enable-cross-compile --extra-cflags=' -O2 -pipe -g -feliminate-unused-debug-types -fmacro-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0=/usr/src/debug/ffmpeg/4.2.1-r0 -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0=/usr/src/debug/ffmpeg/4.2.1-r0 -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot= -fdebug-prefix-map=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot-native= --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot' --extra-ldflags='-Wl,-O1 -Wl,--hash-style=gnu -Wl,--as-needed' --sysroot=/home/andrew/Projects/quicksilver-main/build-quicksilver/tmp/work/aarch64-mx8-klondike-linux/ffmpeg/4.2.1-r0/recipe-sysroot --libdir=/usr/lib --shlibdir=/usr/lib --datadir=/usr/share/ffmpeg --disable-mipsdsp --disable-mipsdspr2 --cpu=generic --pkg-config=pkg-config --disable-static --enable-alsa --enable-avcodec --enable-avdevice --enable-avfilter --enable-avformat --enable-avresample --enable-bzlib --enable-gpl --disable-libgsm --disable-indev=jack --disable-libvorbis --enable-lzma --disable-libmfx --disable-libmp3lame --disable-openssl --enable-postproc --disable-sdl2 --disable-libspeex --enable-swresample --enable-swscale --enable-libtheora --disable-vaapi --disable-vdpau --disable-libvpx --enable-libx264 --disable-libxcb --disable-outdev=xv --enable-zlib
  libavutil      56. 31.100 / 56. 31.100
  libavcodec     58. 54.100 / 58. 54.100
  libavformat    58. 29.100 / 58. 29.100
  libavdevice    58.  8.100 / 58.  8.100
  libavfilter     7. 57.100 /  7. 57.100
  libavresample   4.  0.  0 /  4.  0.  0
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Unknown input format: 'v4l2_m2m'

Thanks for the link I will try to learn more about v4l2_m2m.

~ Andrew