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• H.264 video file size from camera is much bigger than x264 output

  10 août 2020, par Lawrence song

  I have a UVC camera which supports h264 protocol. we can see the h264 listed below when we list all formats supported.

  


  msm8909:/data # ./ffmpeg -f v4l2 -list_formats all -i /dev/video1
ffmpeg version N-53546-g5eb4405fc5-static https://johnvansickle.com/ffmpeg/  Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 6.3.0 (Debian 6.3.0-18+deb9u1) 20170516
  configuration: --enable-gpl --enable-version3 --enable-static --disable-debug --disable-ffplay --disable-indev=sndio --disable-outdev=sndio --cc=gcc --enable-fontconfig --enable-frei0r --enable-gnutls --enable-gmp --enable-libgme --enable-gray --enable-libfribidi --enable-libass --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librubberband --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libvorbis --enable-libopus --enable-libtheora --enable-libvidstab --enable-libvo-amrwbenc --enable-libvpx --enable-libwebp --enable-libx264 --enable-libxml2 --enable-libxvid --enable-libzimg
  libavutil      56. 56.100 / 56. 56.100
  libavcodec     58. 97.100 / 58. 97.100
  libavformat    58. 49.100 / 58. 49.100
  libavdevice    58. 11.101 / 58. 11.101
  libavfilter     7. 87.100 /  7. 87.100
  libswscale      5.  8.100 /  5.  8.100
  libswresample   3.  8.100 /  3.  8.100
  libpostproc    55.  8.100 / 55.  8.100
[video4linux2,v4l2 @ 0x4649140] Compressed:        h264 :                H.264 : 1920x1080 1280x720 640x480 320x240
[video4linux2,v4l2 @ 0x4649140] Compressed:       mjpeg :                MJPEG : 1920x1080 1280x720 640x480 320x240


  


  I am running the ffmpeg cmd to record UVC camera video to local device.

  


  ffmpeg -f v4l2 -input_format h264 -framerate 30 -video_size 1280*720 -i /dev/video1 -c copy /sdcard/Movies/output.mkv


  


  The video size is way bigger than running the command below :

  


  ffmpeg -f v4l2 -input_format mjpeg -framerate 30 -video_size 1280*720 -i /dev/video1 -c:v libx264 -vf format=yuv420p /sdcard/Movies/output.mp4


  


  I assume the camera already supports h264 protocol. Thus I don't need to re-encode to 264 formats. However, the video size does not look like an H264 encoded video.

  


• Can't list input devices ffmpeg linux

  23 juillet 2021, par spindi598

  On windows I could do something like this to list input devices :

  


  ffmpeg -list_devices true -f dshow -i dummy


  


  On Linux I try doing something like this :

  


  ffmpeg -list_devices true -f <x11grab></x11grab>avfoundation>&#xA;

  


  And I get an error (I have also tried the latest git build from here) :

  


  ffmpeg version n4.2.4 Copyright (c) 2000-2020 the FFmpeg developers
  built with gcc 10.1.0 (GCC)
  configuration: --prefix=/usr --disable-debug --disable-static --disable-stripping --enable-avisynth --enable-fontconfig --enable-gmp --enable-gnutls --enable-gpl --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libdav1d --enable-libdrm --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libiec61883 --enable-libjack --enable-libmfx --enable-libmodplug --enable-libmp3lame --enable-libopencore_amrnb --enable-libopencore_amrwb --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-libsoxr --enable-libspeex --enable-libsrt --enable-libssh --enable-libtheora --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxcb --enable-libxml2 --enable-libxvid --enable-nvdec --enable-nvenc --enable-omx --enable-shared --enable-version3
  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
  libswscale      5.  5.100 /  5.  5.100
  libswresample   3.  5.100 /  3.  5.100
  libpostproc    55.  5.100 / 55.  5.100
Unrecognized option 'list_devices'.
Error splitting the argument list: Option not found


  


  How can I list my input devices ?

  


• How to do multiple input with streamio-ffmpeg ?

  12 août 2020, par Yozuu

  I would like to recreate this ffmpeg line (which works well) in my rails app :

  


  ffmpeg -i 1.mp4 -i 2.mp4 -filter_complex '[0] [1] afir=dry=10:wet=10' output.wav


  


  So here is my config :

  


  module EncodingConstants
  PROCESSED_DEFAULTS = {
    resolution:           '500x400',
    video_codec:          'libx264',
    constant_rate_factor: '30',
    frame_rate:           '25',
    audio_codec:          'aac',
    audio_bitrate:        '128k',
    audio_sample_rate:    '48000',
    progress: :processing_progress
  }.freeze

  AUDIO_EFFECTS = {
    multi_effect: %w[-i /home/yozuu/2.mp4 -filter_complex [0] [1] afir=dry=10:wet=10]
 }.freeze


  


  So Sidekiq send this back to me :

  


  I, [2020-08-12T19:40:38.828081 #2142]  INFO -- : Running transcoding...
["/sbin/ffmpeg", "-y", "-i", "/home/yozuu/labo/video-project/tmp/1597254011-2142-0001-8820/1.mp4", "-vcodec", "libx264", "-acodec", "aac", "-s", "500x282", "-i", "/home/yozuu/2.mp4", "-filter_complex", "'[0]", "[1]", "afir=dry=10:wet=10'", "-r", "25", "-b:a", "128k", "-ar", "48000", "-aspect", "1.7730496453900708", "/home/yozuu/labo/video-project/tmp/1597254011-2142-0001-8820/1.mp4"]

E, [2020-08-12T19:40:38.897575 #2142] ERROR -- : Failed encoding...
["/sbin/ffmpeg", "-y", "-i", "/home/yozuu/labo/video-project/tmp/1597254011-2142-0001-8820/1.mp4", "-vcodec", "libx264", "-acodec", "aac", "-s", "500x282", "-i", "/home/yozuu/2.mp4", "-filter_complex", "'[0]", "[1]", "afir=dry=10:wet=10'", "-r", "25", "-b:a", "128k", "-ar", "48000", "-aspect", "1.7730496453900708", "/home/yozuu/labo/video-project/tmp/1597254011-2142-0001-8820/1.mp4"]


.....

Unknown decoder 'libx264'

Errors: no output file created. 



  


  I don't understand why because for me the command line ffmpeg seems correct.
Anyone have a idea ?
Thank you.