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• Conversion to yuv422p pixel format is incorrect

  13 mars 2023, par SOSparachuter1

  The setup :

  


  


  1. A camera that live streams h.264 encoded video via RTSP

     


  


  2. An Android app that uses FFMPEG to grab H.264 packet fragments, convert it to mjpeg frames with pixel format yuv422.

     


  


  3. A separate app that receives said jpeg images over udp, expects them to be in yuv422 pixel format, and displays the stream.

     


  


  


  The bridge between all these components work perfectly, #2 gets frames and sends it to #3, and #3 verifies it receives. However, #3 would not display, and so upon closer inspection of the packets it receives, I discovered in the jpeg image header for every packet that the horizontal-vertical subsampling factor was not what is expected for YUV422. It's 0x22, despite the fact that for YUV422 we should expect halved horizontal chroma resolution (so we should expect 0x21)

  


  This is the ffmpeg command I use :

  


  ffmpeg -i rtsp://****:*** -vcodec mjpeg -pix_fmt yuv422p -f mjpeg udp://*******

  


  What could be going on ? Does the default codec just not support this conversion ?

  


• yuv420p10le format using ffmpeg without green background in web browser

  16 août 2021, par OneWorld

  I just rebuilt ffmpeg, and generated a yuv420p10le video. Below is a snapshot from the video.

  


  

  


  It seems to display a green background in chrome when I play it. However, if I switch hardware acceleration off in Chrome, the background appears white. Also if I play the video in VLC player the background is white.

  


  I was wondering if there is a way within ffmpeg to get yuv420p10le to show backgrounds as white in browsers without needing to do anything special in the browser settings ?

  


  My ffmpeg configuration is as follows :-

  


  ffmpeg -i after_building_ffmpeg.mp4
ffmpeg version N-103222-gf040c1ec4e Copyright (c) 2000-2021 the FFmpeg developers
  built with gcc 7 (Ubuntu 7.5.0-3ubuntu1~18.04)
  configuration: --enable-gpl --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-librtmp --enable-libtheora --enable-libvorbis --enable-libvpx --enable-libx264 --enable-nonfree --enable-version3 --enable-libxcb
  libavutil      57.  3.100 / 57.  3.100
  libavcodec     59.  4.101 / 59.  4.101
  libavformat    59.  4.101 / 59.  4.101
  libavdevice    59.  0.100 / 59.  0.100
  libavfilter     8.  1.103 /  8.  1.103
  libswscale      6.  0.100 /  6.  0.100
  libswresample   4.  0.100 /  4.  0.100
  libpostproc    56.  0.100 / 56.  0.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'after_building_ffmpeg.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf59.4.101
  Duration: 00:00:03.00, start: 0.000000, bitrate: 5893 kb/s
  Stream #0:0(und): Video: h264 (High 10) (avc1 / 0x31637661), yuv420p10le(tv, gbr/unknown/unknown), 1400x1400 [SAR 1:1 DAR 1:1], 5888 kb/s, 25 fps, 25 tbr, 12800 tbn (default)
    Metadata:
      handler_name    : VideoHandler
      vendor_id       : [0][0][0][0]


  


• NodeMediaServer MP4 change default video resolution 540p

  11 août 2021, par Farooq Zaman

  I have setup a nginx RTMP server and the purpose is to store videos streamed from mobile devices in MP4 format for later analysis. Although mobile devices are streaming videos in 720p resolution NodeMediaServer always store video in 540p resolution. How can I change this behaviour ? Following is NodeMediaServer configuration :

  


  const nodeMediaServerConfig = {
  rtmp: {
    port: 1936,
    chunk_size: 60000,
    gop_cache: true,
    ping: 60,
    ping_timeout: 10,
  },
  http: {
    port: 8000,
    mediaroot: './media',
    allow_origin: '*',
  },
  trans: {
    ffmpeg: '/usr/bin/ffmpeg',
    tasks: [
      {
        app: 'live',
        vcParam: [
          "-c:v",
          "libx264",
          "-vf",
          "scale=720:-1",
          "-b:v",
          "2800k",
          "-bufsize",
          "4200k",
          "-preset",
          "fast",
        ],
        ac: 'aac',
        acParam:["-b:a", "128k", "-ar", 48000],
        mp4: true,
        mp4Flags: '[movflags=faststart]',
      },
    ],
  },
};


  


  Any help in this matter is highly appreciated.