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• avcodec_encode_video2 crash on MinGW32 (but not on MinGW64)

  27 février 2018, par ksb496

  I have been testing for years a software that I am developing, compiled only for 64-bit systems through Qt-MinGW64, without experiencing any kind of issue regarding video encoding (which is one of the features of such application). Recently, I have been attempting to build the corresponding x86 version of my software by compiling it with Qt-MingGW32.

  However, after bulding the same ffmpeg and x264 library versions to create the 32-bit versions and successfully linking them to my project, the application keeps crashing after few frames are encoded, due to segmentation fault error. This is very strange because, as I indicated before, it works flawlessly when compiled for 64-bit systems.

  I have also lost a considerable amount hours trying to combine a big amount of different versions of both ffmpeg and x264 libraries, but with no luck either. Neither it works when disabling threads both for x264 and ffmpeg libraries, hence it does not seem to be a win32 threading issue. Therefore, I have concluded that the error is most likely in my code, which by some chance beyond my comprehension tells ffmpeg to allocate the right amount of memory in the x64 version, but not in the x86 version.

  It must be pointed out also that before the avcodec_encode_video2 call, I do the following calls, among others, in order to allocate the memory associated to the corresponding items (AVFrame, AVCodec, etc.), such as

  avcodec_open2( my_codec_context, my_codec, &opt );
  
  my_av_frame=av_frame_alloc();

  More precisely, the details involving the code structure that I am using can be found here.

  Therefore, the error appears to be more subtle than just issues regarding uninitialized memory.

  Many thanks in advance.

  UPDATE :

  I have discovered the focus of the problem. For some reason, FFmpeg/x264 libraries behave abnormally in Win32 GUI applications compiled with Qt-MinGW32, while they run correctly in Win32 console applications, also compiled with Qt-WinGW32. I have proven this claim performing two dummy tests, in which the exact same piece of code is run through a console application and on a GUI application, succeeding in the first case and failing in the latter one. The code for such tests can be found below, along with the x264 and FFmpeg libraries used in my projects, together with instructions to build them in msys2 with MinGW32 :

  https://takeafile.com/?f=hisusinivi

  I have no idea whether it can be solved by simply tweaking the code or it is a serious bug involving an incompatibility issue. If it is the latter, should it be reported to the Qt/FFmpeg/x264 staff as a major bug ?

• FFMPEG Crash in Windows when trying to create chroma key for image

  24 février 2018, par Kavinda Keshan Rasnayake

  I tried to execute this command in Windows 10 for ffmpeg to create a chroma key :

  ffmpeg -i input.png -vf colorkey=green out.png

  However, using this command crashes ffmpeg.

  What can I do to mitigate this problem ?

  I am using ffmpeg 3.4

  edit : - Here is what is displayed on console

  ffmpeg version 3.4 Copyright (c) 2000-2017 the FFmpeg developers
  
    built with gcc 7.2.0 (GCC)
  
    configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-bzlib --enable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libshine --enable-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp --enable-libvidstab --enable-libvorbis --enable-cuda --enable-cuvid --enable-d3d11va --enable-nvenc --enable-dxva2 --enable-avisynth --enable-libmfx
  
    libavutil      55. 78.100 / 55. 78.100
  
    libavcodec     57.107.100 / 57.107.100
  
    libavformat    57. 83.100 / 57. 83.100
  
    libavdevice    57. 10.100 / 57. 10.100
  
    libavfilter     6.107.100 /  6.107.100
  
    libswscale      4.  8.100 /  4.  8.100
  
    libswresample   2.  9.100 /  2.  9.100
  
    libpostproc    54.  7.100 / 54.  7.100
  
  Input #0, png_pipe, from '.\e2.png':
  
    Duration: N/A, bitrate: N/A
  
      Stream #0:0: Video: png, rgba(pc), 480x480, 25 tbr, 25 tbn, 25 tbc
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (png (native) -> png (native))
  
  Press [q] to stop, [?] for help
  
  Output #0, image2, to 'out.png':
  
    Metadata:
  
      encoder         : Lavf57.83.100
  
      Stream #0:0: Video: png, rgba, 480x480, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
  
      Metadata:
  
        encoder         : Lavc57.107.100 png

• hwcontext_d3d11 : Fix crash with valid adapter but no device

  27 mars 2018, par Mark Thompson

  hwcontext_d3d11 : Fix crash with valid adapter but no device
  This crash was introduced by 8bbf2dacbfb4ead1535dea411035994f507f517d,
  
  which could incorrectly overwrite the failure result from creating the
  
  device.
  Fixes ticket #7108.
  Reviewed-by : wm4 <nfxjfg@googlemail.com>
  

  • [DH] libavutil/hwcontext_d3d11va.c