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• Muxing encoder output with custom io in ffmpeg

  3 mai 2021, par MisterSincere

  I am having some basic issues on how to mux my encoder results into a mp4 file. My current approach is to create a custom AVFormatContext, where the DataProvider is the encoder :

  


  AVFormatContext *create_format_context(DataProvider *pDataProvider) {
  AVFormatContext *ctx{avformat_alloc_context()};

  size_t   bufSize{8 * 1024 * 1024};
  uint8_t *avBuffer{(uint8_t*)av_malloc(bufSize)};

  ctx->pb = avio_alloc_context(avBuffer,
                               bufSize,
                               0,
                               pDataProvider,
                               DataProvider::read,
                               nullptr,
                               nullptr);

  ctx->flags |= AVFMT_FLAG_CUSTOM_IO;

  FFMPEG_CALL(avformat_open_input(&ctx, nullptr, nullptr, nullptr));
  return ctx;
}


  


  But I crash on avformat_open_input with the following error message :

  


  


  Invalid data found when processing input

  


  


  It tries to read for the first time from the encoder, but since this is at init-time, the encoder doesn't have any results yet. I figured the problem is that ffmpeg tries to query for some header informations, since it would feel weird to ask for actual data when just opening.
  
How do I provide that header information / where can I learn something about how this header should look like and what else I need to provide for ffmpeg ?
  
Or is there even a completely different approach, because quite honestly I would be happy if I could feed the per frame encoded data directly to ffmpeg instead of through this whole context abstraction.

  


  For context I pasted the muxer class, I guess the progress() function is the most interesting one, here header, source.

  


  Also I call the kinda magic functions

  


  av_register_all();
avcodec_register_all();
avformat_network_init();


  


  before everything else concerning ffmpeg.

  


  The encoder is not written with ffmpeg, but with cuda / the nvidia video sdk for hardware acceleration purposes.

  


• Best way to convert video from h264 to h265 and copy audio without lose too match quality

  9 mai 2021, par user3449922

  I have some mkv file ripped from blu ray and I like to convert it to h265 with ffmpeg.

  


  I have tried this command :

  


  ffmpeg.exe -i title00.mkv -c:v hevc_nvenc test_2.mkv


  


  and the result seem incredible : original size : 27 GB , output size : 1.6 GB

  


  Francanly I don't expect a similar result that is very strange.

  


  The quality seem similar at the fist look, but I don't belive it.

  


  I ask if there is a better way to preserve the original quality and it is not important if the output size is 4 or 5 GB that is in all cases a excellet result.

  


  I have Nvidia GTX 1060 6GB

  


  Can you suggest me a best way to do it ?

  


• Best way to convert video from h264 to h265 and copy audio without lose too much quality [closed]

  11 mai 2021, par user3449922

  I have some mkv file ripped from blu ray and I like to convert it to h265 with ffmpeg.

  


  I have tried this command :

  


  ffmpeg.exe -i title00.mkv -c:v hevc_nvenc test_2.mkv


  


  and the result seem incredible : original size : 27 GB , output size : 1.6 GB

  


  Francanly I don't expect a similar result that is very strange.

  


  The quality seem similar at the fist look, but I don't belive it.

  


  I ask if there is a better way to preserve the original quality and it is not important if the output size is 4 or 5 GB that is in all cases a excellet result.

  


  I have Nvidia GTX 1060 6GB

  


  Can you suggest me a best way to do it ?