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• Does AVFrame store AV_PIX_FMT_YUV420P data as YVU ?

  28 juin 2017, par Peter

  I am decoding raw H.265 data using avcodec_decode_video2 api. When I examine the resulting instance pictYUV of type AVFrame, I see that pictYUV->format is AV_PIX_FMT_YUV420P and pictYUV->data[0] points to Y-plane. Both of these are expected. However, it appears pictYUV->data[1] seem to contain V-plane data and pictYUV->data[2]seem to contain U-plane data. My intuition was that pictYUV->data would store YUV planes in that order and not YVU planes. Wondering if the data is always ordered as YVU or is there some flag I failed to look at. Regards.

• Lossless codec for bayer data

  21 août 2016, par vhdirk

  I’m working with lots of camera’s which capture in BG bayer pattern natively.

  Now, every time I record some data, I save it to the disk in the raw bayer pattern, in an avi container. The problem is, that this really adds up after a while. After one year of research, I have close to 4TB of data...

  So I’m looking for a lossless codec to compress this data. I know I could use libx264 (with —qp 0), or huffYUV, dirac or jpeg2000, but they all assume you have RGB or YUV data. It’s easy enough to convert the bayered data to RGB, and then compress it, but it kind of defeats the purpose of compression if you first triple the data. This would also mean that the demoasicing artefacts introduced by debayering would also be in my source data, which is also not too great. It would be nice to have a codec that can work on the bayered data directly.

  Even more nice would be that the solution would involve a codec that is already supported by gstreamer (or ffmpeg), since that’s what I am already using.

• ffmpeg Unrecognized option 'tune'

  27 décembre 2016, par sangjun

  I’m using ffmpeg on node.js. And option ’-tune zerolatency’ for low latency

  But when I insert "-tune zerolatency", I get an error : Unrecognized option ’tune’.

  Can anyone help ? I have no idea what to do.

  Here’s the script.

  let token = '@!#!@#%@$@#%#^^!@$@#$@#$@#$^@#$'
  
  let option = [
  
      '-i', 'pipe:0', //mpeg4
  
      '-acodec', 'copy',
  
      '-vcodec', 'copy',
  
      '-s', '284x164',
  
      '-preset', 'ultrafast',
  
      '-tune', 'zerolatency',
  
      '-f', 'flv',
  
      'rtmp://localhost:1935/s/' + token,
  
  ];
  
  ffmpeg = spawn("ffmpeg", option);
  
  
  
  ffmpeg.stdin.write(streaming_data);

  Here’s the ffmpeg version

  ffmpeg version N-82166-g894e7ef Copyright (c) 2000-2016 the FFmpeg developers
  
    built with gcc 4.8.3 (GCC) 20140911 (Red Hat 4.8.3-9)
  
    configuration: --prefix=/usr/local/ffmpeg_build --extra-cflags=-I/usr/local/ffmpeg_build/include --extra-ldflags=-L/usr/local/ffmpeg_build/lib --bindir=/usr/local/bin
  
    libavutil      55. 35.100 / 55. 35.100
  
    libavcodec     57. 65.100 / 57. 65.100
  
    libavformat    57. 57.100 / 57. 57.100
  
    libavdevice    57.  2.100 / 57.  2.100
  
    libavfilter     6. 66.100 /  6. 66.100
  
    libswscale      4.  3.100 /  4.  3.100
  
    libswresample   2.  4.100 /  2.  4.100