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• ffmpeg sws_scale converting from YUV420P to RGB24 results in wrong color values

  3 novembre 2016, par Drazurh

  I’m using sws_scale to convert a video from YUV420P to RGB24. The resulting RGB values are wrong, looking much more saturated/contrasted. For example, the first pixel should have an RGB value of (223,73,30) but using sws_scale results in (153,0,0).

  Here’s the code I’m using :

  uint8_t *buffer = NULL;
  
  int numBytes;
  
  // Determine required buffer size and allocate buffer
  
  numBytes=avpicture_get_size(PIX_FMT_RGB24, pCodecCtx->width,
  
                             pCodecCtx->height);
  
  buffer=(uint8_t *)av_malloc(numBytes*sizeof(uint8_t));
  
  
  
  // Assign appropriate parts of buffer to image planes in pFrameRGB
  
  // Note that pFrameRGB is an AVFrame, but AVFrame is a superset
  
  // of AVPicture
  
  std::cout << "Filling picture of size " << pCodecCtx->width <<" x "<height << std::endl;
  
  avpicture_fill((AVPicture *)pFrameRGB, buffer, PIX_FMT_RGB24,
  
                  pCodecCtx->width, pCodecCtx->height);
  
  
  
  
  
  
  
  // initialize SWS context for software scaling
  
  std::cout << "initializing SWS context\n";
  
  sws_ctx = sws_getContext(pCodecCtx->width,
  
      pCodecCtx->height,
  
      pCodecCtx->pix_fmt,
  
      pCodecCtx->width,
  
      pCodecCtx->height,
  
      PIX_FMT_RGB24,
  
      SWS_FAST_BILINEAR,
  
      NULL,
  
      NULL,
  
      NULL
  
  );
  
  
  
  while(frameFinished == 0)
  
  {
  
      if(av_read_frame(pFormatCtx, &packet)<0){
  
          std::cerr << "Could not read frame!\n";
  
          return false;
  
      }
  
  
  
      if(packet.stream_index==videoStream)
  
      {
  
          avcodec_decode_video2(pCodecCtx, pFrame, &frameFinished, &packet);
  
      }
  
  
  
  }
  
  
  
  sws_scale(sws_ctx, (uint8_t const * const *)pFrame->data,
  
            pFrame->linesize, 0, pCodecCtx->height,
  
            pFrameRGB->data, pFrameRGB->linesize);

  The values in pFrameRGB are incorrect. I’ve tried troubleshooting this for hours :-( Any ideas on how to track down my mistake ?

  Here’s a link to the repo. The offending code is in Icosahedron Video Player/mesh.cpp, Mesh::LoadVideo and Mesh::NextFrame().

• avcodec/wavpack : add support for DSD files

  9 mars 2020, par David Bryant

  avcodec/wavpack : add support for DSD files
  Add support for WavPack DSD files to the existing WavPack decoder using
  
  avcodec/dsd to perform the 8:1 decimation to 32-bit float samples. We must
  
  serialize the dsd2pcm operation (cross-boundary filtering) but would like
  
  to use frame-level multithreading for the CPU-intensive DSD decompression,
  
  and this is accomplished with ff_thread_report/await_progress(). Because
  
  the dsd2pcm operation is independent across channels we use slice-based
  
  multithreading for that part.
  Also a few things were removed from the existing WavPack decoder that
  
  weren't being used (primarily the SavedContext stuff) and the WavPack
  
  demuxer was enhanced to correctly determine the sampling rate of DSD
  
  files (and of course to no longer reject them).
  Signed-off-by : David Bryant <david@wavpack.com>
  

  • [DH] libavcodec/Makefile
  • [DH] libavcodec/wavpack.c
  • [DH] libavcodec/wavpack.h
  • [DH] libavformat/wvdec.c

• x86inc : Add debug symbols indicating sizes of compiled functions

  18 janvier 2016, par Geza Lore

  x86inc : Add debug symbols indicating sizes of compiled functions
  Some debuggers/profilers use this metadata to determine which function a
  
  given instruction is in ; without it they get can confused by local labels
  
  (if you haven’t stripped those). On the other hand, some tools are still
  
  confused even with this metadata. e.g. this fixes `gdb`, but not `perf`.
  Currently only implemented for ELF.
  Signed-off-by : Anton Khirnov <anton@khirnov.net>
  

  • [DBH] libavcodec/x86/proresdsp.asm
  • [DBH] libavutil/x86/x86inc.asm
  • [DBH] tests/checkasm/x86/checkasm.asm