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• Legal issues regarding proprietary_codecs in chromium (bundled with electron)

  4 juin 2021, par Manmohan Singh

  We're in the process of building and deploying a desktop based app on electron v 12.0.7. It'll be a (free) commercial software deployed to 2-3M users worldwide.
Recently our legal team enquired about the proprietary codecs bundled with chromium and I thought the best way to confirm this would be to reach out here.

  


  So, here're specific things that I need help with :

  


  


  1. Are we shipping chromium with proprietary codecs ? If yes, what are potentially contentious codecs that come by default in chromium bundled with electron v 12.0.7 ?

     


  


  2. Is there any documentation around how the electron team builds chromium (with what flags) ?

     


  


  3. Is the default libffmpeg.dylib/dll bundled with electron building ffmpeg with support for things like H.264 and MP3 codecs ?

     


  


  4. I noticed there are libffmpeg binaries available with each electron build, e.g. https://github.com/electron/electron/releases/download/v12.0.7/ffmpeg-v12.0.7-darwin-arm64.zip . What's the purpose of this binary ?

     


  


  


  Any help would be appreciated.

  


• Issues when decoding video via ffmpeg with dxva2

  5 janvier 2016, par CD83

  I have successfully implemented a video player using ffmpeg. I am now trying to use hardware decoding but I’m facing a couple issues.
  I found a post that I followed as a starting point here : http://comments.gmane.org/gmane.comp.video.ffmpeg.libav.user/13523

  I have updated the code that setup the necessary stuff for the decoder. The updated code is available here : https://drive.google.com/file/d/0B5ufHdoDzA4ieVk5UVpxcDNzRHc/view?usp=sharing

  And this is how I’m using it to initialize the decoder :

  // Prepare the decoding context
  
  AVCodec *codec = nullptr;
  
  _codecContext = _avFormatContext->streams[_streamIndex]->codec;
  
  if ((codec = avcodec_find_decoder(_codecContext->codec_id)) == 0)
  
  {
  
      std::cout << "Unsupported video codec!" << std::endl;
  
      return false;
  
  }
  
  
  
  _codecContext->thread_count = 1;  // Multithreading is apparently not compatible with hardware decoding
  
  InputStream *ist = new InputStream();
  
  ist->hwaccel_id = HWACCEL_AUTO;
  
  ist->hwaccel_device = "dxva2";
  
  ist->dec = codec;
  
  ist->dec_ctx = _codecContext;
  
  _codecContext->coded_width = _width;
  
  _codecContext->coded_height = _height;
  
  
  
  _codecContext->opaque = ist;
  
  dxva2_init(_codecContext);
  
  
  
  _codecContext->get_buffer2 = ist->hwaccel_get_buffer;
  
  _codecContext->get_format = GetHwFormat;
  
  _codecContext->thread_safe_callbacks = 1;
  
  
  
  if (avcodec_open2(_codecContext, codec, nullptr) < 0)
  
  {
  
      std::cout << "Video codec open error" << std::endl;
  
      return false;
  
  }

  And here is the definition of GetHwFormat referenced above :

  AVPixelFormat GetHwFormat(AVCodecContext *s, const AVPixelFormat *pix_fmts)
  
  {
  
      InputStream* ist = (InputStream*)s->opaque;
  
      ist->active_hwaccel_id = HWACCEL_DXVA2;
  
      ist->hwaccel_pix_fmt = AV_PIX_FMT_DXVA2_VLD;
  
      return ist->hwaccel_pix_fmt;
  
  }

  When I open an mp4 (encoded in h264) video that is HD resolution or less, everything seems to be working fine. However, as soon as I try higher resolution videos like 3840x2160, I get the following errors repeatedly :

  Failed to execute: 0x80070057
  
  Hardware accelerator failed to decode picture

  I also start getting the following errors after a few seconds :

  co located POCs unavailable

  And the video is not displayed properly : I get a lot of artifacts all over the video and it is lagging. I checked the first error in the ffmpeg source code. It seems that IDirectXVideoDecoder_Execute fails because of an invalid parameter. Since this is happening withing ffmpeg, there must be something that I’m missing but I can’t figure out what. The only relevant post that I found with this error was because of multithreading but I set the thread_count to 1 before opening the codec.

  This issue is happening on my main computer which has the following specs :

  • i7-4790 CPU @ 3.6GHz
  • RAM 16 GB
  • Intel HD Graphics 4600
  • Windows 8.1

  The same issue is not happening on my second computer which has the following specs :

  • i7 4510U @ 2GHz
  • RAM 8 GB
  • NVIDIA GeForce GTX 750Ti
  • Windows 10

  If I use DXVAChecker on my main computer, it says that my graphics card supports DXVA2 for H264_VLD_*, and I can see that the calls to the Microsoft API are being made (DXVA2_DecodeDeviceCreated, DXVA2_DecodeDeviceBeginFrame, DXVA2_DecodeDeviceGetBuffer, DXVA2_DecodeDeviceExecute, DXVA2_DecodeDeviceEndFrame) while my video is playing.

  I also don’t see any increase of GPU usage (on either computer) between the version with hardware decoding and the version without ; however, I do see a decrease in CPU usage (not as much as I was expecting though). This is also very strange.

  Note that I tried both the Windows release available on the FFmpeg website, and a version that I compiled with —enable-dxva2. I have searched a lot already but I was unable to find what I’m doing wrong.

  Hopefully, someone can help me, or maybe point me to a better example ?

• FFMPEG Audio Issues Youtube Live

  2 mars 2018, par Geige V

  This issue may have more to do with youtube than ffmpeg, but hopefully someone can help anyway.

  I am having the exact issue described in this post https://productforums.google.com/forum/# !topic/youtube/nHTb7ilKvrw. I would have added to it, but it is locked for some reason.

  I create a stream from a local webm file on my computer using ffmpeg. This file sounds perfectly fine, and still sounds fine when it is sent to platforms other than youtube live (twitch/facebook). On youtube live, however, the audio has static and crackles during the live feed, but the archive of the video on youtube (after processing) sounds perfectly fine. The ffmpeg command is

  ffmpeg -re -i test.webm -acodec aac -vcodec libx264 -ar 44100 -f flv rtmp://a.rtmp.youtube.com/live2/${your_key}

  Webm files from this fiddle (https://jsfiddle.net/2rgv7pgj/) will have the issue.

  If someone could offer advice it would be greatly appreciated.