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• FFMpeg, libav, Problem with sws_scale and yuv to rgb conversion - colors are not correct

  7 juillet 2022, par Milika

  I've been trying to create my own video player in Delphi, and ffmpeg works great, until i hit a snag with color spaces, or color conversion.

  


  Been trying everything for a couple of days, but can't figure it out.
I'm using AV_PIX_FMT_RGB48LE as output...

  


  Old context creation :

  


        videoConvContext := sws_getContext(AVStreamInit.codec.width, AVStreamInit.codec.height, AVStreamInit.codec.pix_fmt, AVStreamInit.codec.width, AVStreamInit.codec.height, AV_PIX_FMT_RGB48LE, SWS_POINT, nil, nil, nil);


  


  New context creation :

  


      dstRange := 1;
    srcRange := 1;
    if AVStreamInit.codec.color_range = AVCOL_RANGE_MPEG then
      srcRange := 0;

    videoConvContext := sws_alloc_context();

    av_opt_set_int(videoConvContext, 'sws_flags', SWS_POINT or SWS_PRINT_INFO, 0);

    av_opt_set_int(videoConvContext, 'srcw', AVStreamInit.codec.width, 0);
    av_opt_set_int(videoConvContext, 'srch', AVStreamInit.codec.height, 0);
    av_opt_set_int(videoConvContext, 'src_format', Integer(AVStreamInit.codec.pix_fmt), 0);

    av_opt_set_int(videoConvContext, 'dstw', AVStreamInit.codec.width, 0);
    av_opt_set_int(videoConvContext, 'dsth', AVStreamInit.codec.height, 0);
    av_opt_set_int(videoConvContext, 'dst_format', Integer(AV_PIX_FMT_RGB48LE), 0);

    i1 := sws_getCoefficients2(Integer(AVStreamInit.codec.colorspace));
    i2 := sws_getCoefficients2(SWS_CS_ITU709);

    ret := sws_setColorspaceDetails2(videoConvContext, i1, srcRange, i2, dstRange, 0, 1 shl 16, 1 shl 16);

    sws_init_context(videoConvContext, nil, nil);


  


  Results are exactly the same....

  


  Output from sws_scale does not have correct colors, here are 2 screenshot

  


  ok - from mpc-hc


  


  not ok - from my player via sws_scale (direct raw extract so no color processing done)


  


  This video has pix_fmt AV_PIX_FMT_YUV420P10LE, but it happens on other YUV inputs, but not so obvious. Also on other RGB outputs(8bit etc)...
Here the Netflix logo is pure red, but sws_scale output gives orange-ish...

  


  Sws_scale code just for reference :

  


  sws_scale(videoConvContext, @AVPacketBuffer.AVFrameCopy.Data, @AVPacketBuffer.AVFrameCopy.linesize, 0, AVStream.codec.height, @BitmapXBuffer.data, @linesize);


  


  BitmapXBuffer.data is a signle buffer of correct size...

  


  AVFrameCopy - is a copy of original frame done with :

  


    if Assigned(AVPacketBuffer.AVFrameCopy) then
      av_frame_free(@AVPacketBuffer.AVFrameCopy);

    AVPacketBuffer.AVFrameCopy := av_frame_alloc();
    AVPacketBuffer.AVFrameCopy.format := AVPacketBuffer.AVFrame.format;
    AVPacketBuffer.AVFrameCopy.width := AVPacketBuffer.AVFrame.width;
    AVPacketBuffer.AVFrameCopy.height := AVPacketBuffer.AVFrame.height;
    AVPacketBuffer.AVFrameCopy.channels := AVPacketBuffer.AVFrame.channels;
    AVPacketBuffer.AVFrameCopy.channel_layout := AVPacketBuffer.AVFrame.channel_layout;
    AVPacketBuffer.AVFrameCopy.nb_samples := AVPacketBuffer.AVFrame.nb_samples;
    av_frame_get_buffer(AVPacketBuffer.AVFrameCopy, 32);
    av_frame_copy(AVPacketBuffer.AVFrameCopy, AVPacketBuffer.AVFrame);
    av_frame_copy_props(AVPacketBuffer.AVFrameCopy, AVPacketBuffer.AVFrame);


  


  Thanks !

  


• H.264 Codecs for Chromium [closed]

  5 juin 2020, par Aten

  I have been using Chromium for a while, but I found was that I can't watch Netflix because the H.264 codecs are not available. I have already done some research on this, but nothing works. I have tried :

  



  sudo apt install ubuntu-restricted-extras

  



  sudo apt install chromium-codecs-ffmpeg

  



  sudo apt install chromium-codecs-ffmpeg-extra

  



  (These install fine)

  



  sudo apt install chromium-codecs-ffmpeg-nonfree
Which is not found.

  



  I am using Linux Mint 19.3 64-bit (Based on Ubuntu 18.04 LTS) but Ubuntu solutions should work just fine. I am also using Chromium 83.0.4103.61 using sudo :

  



  sudo apt install chromium-browser

  


• FFmpeg Error "No such filter : 'libvmaf' Mac

  4 janvier 2021, par ringola27

  I want to use FFmpeg to calculate PSNR for video sequences.
At first I installed libvmaf with the instruction from here and here. I installed ffmpeg like here. I tried for a test :

  



  ffmpeg -i output4.mpg -i output1.mpg -lavfi libvmaf -f null -


  



  But I get an Error (below). I think I could solve it with ./configure --enable-libvmaf --enable-version3 or ./configure --enable-libvmaf but unfortunately I can not run it (I don't know how).

  



  I hope anyone can help me to solve this problem.

  



  ffmpeg version 4.2.3 Copyright (c) 2000-2020 the FFmpeg developers
  built with Apple clang version 11.0.3 (clang-1103.0.32.59)
  configuration: --prefix=/usr/local/Cellar/ffmpeg/4.2.3 --enable-shared --enable-pthreads --enable-version3 --enable-avresample --cc=clang --host-cflags=-fno-stack-check --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libbluray --enable-libdav1d --enable-libmp3lame --enable-libopus --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-librtmp --enable-libspeex --enable-libsoxr --enable-videotoolbox --disable-libjack --disable-indev=jack
  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
Input #0, mpeg, from 'output4.mpg':
  Duration: 00:00:09.88, start: 0.533367, bitrate: 363 kb/s
    Stream #0:0[0x1e0]: Video: mpeg1video, yuv420p(tv), 352x288 [SAR 178:163 DAR 1958:1467], 104857 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 29.97 tbc
Input #1, mpeg, from 'output1.mpg':
  Duration: 00:00:10.01, start: 0.533367, bitrate: 345 kb/s
    Stream #1:0[0x1e0]: Video: mpeg1video, yuv420p(tv), 352x288 [SAR 178:163 DAR 1958:1467], 104857 kb/s, 29.97 fps, 29.97 tbr, 90k tbn, 29.97 tbc
[AVFilterGraph @ 0x7ffedbe23180] No such filter: 'libvmaf'
Error initializing complex filters.
Invalid argument