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• Enabling mp4/mpeg4/avc support for Qt5 WebEngine on Linux

  12 avril 2016, par Thomas233

  i installed Qt 5.4.1 x64 on LUbuntu and created an app which uses the new QtWebEngine.

  I`m trying to display a html5 page with that component which is using the tag.
  All works fine except if I try to playback a mp4 video. The video area remains black. It works if I use other video types like webm/ogg as source.

  I know this is due to license restrictions, so that mp4 is deactivated by default in Ubuntu/Linux for Qt.

  What is needed in Qt to activate it to allow mp4 playback and on what do I have pay attention in case of license terms (I read that statically linking the library is allowed ?) ?

  I`ve already tried to copy over the x64 distribution of libffmpegsuo.so which is included in Chrome (2,2Mb) over to the Qt directory to /plugins/webengine/ and replaced that one that was already there (1,1 Mb) but it had no effect.
  In Chrome playback works fine btw.

  If you need more details like paths etc. please tell me.

  Thanks !

• Enabling mp4/mpeg4/avc playback in Qt 5.4 webengine on Ubuntu x64

  14 janvier 2016, par Thomas233

  i installed Qt 5.4.1 x64 on LUbuntu and created an app which uses the new QtWebEngine.

  I`m trying to display a html5 page with that component which is using the tag.
  All works fine except if I try to playback a mp4 video. The video area remains black. It works if I use other video types like webm/ogg as source.

  I know this is due to license restrictions, so that mp4 is deactivated by default in Ubuntu/Linux for Qt.

  What is needed in Qt to activate it to allow mp4 playback and on what do I have pay attention in case of license terms (I read that statically linking the library is allowed ?) ?

  I`ve already tried to copy over the x64 distribution of libffmpegsuo.so which is included in Chrome (2,2Mb) over to the Qt directory to /plugins/webengine/ and replaced that one that was already there (1,1 Mb) but it had no effect.
  In Chrome playback works fine btw.

  If you need more details like paths etc. please tell me.

  Thanks !

• FFMPEG get_buffer2 multi-thread random crash

  4 novembre 2015, par arnaud

  I’m doing a multi-thread FFMPEG video player. Basically it decodes and display 16 MP4 video files ( using h264 codec ) at the same time, using my own threads / jobs subsystem.
  For future extension I want to provide my own memory buffer for AVFrame decoding. To do this, I simply used get_buffer2 hook method. My get_buffer2 handles currently only use av_malloc & av_free (to validate everything is working ). Here is my handler :

  void our_buffer_default_free(void *opaque, uint8_t *data)
  
  {
  
      av_free(data);
  
  }
  
  
  
  int our_get_buffer(struct AVCodecContext *c, AVFrame *pic, int flags)
  
  {
  
      assert(c->codec_type == AVMEDIA_TYPE_VIDEO);
  
  
  
      pic->linesize[0] = pic->width;
  
      pic->linesize[1] = pic->width/2;
  
      pic->linesize[2] = pic->width/2;
  
  
  
      void* pYBuffer = av_malloc(pic->linesize[0] * pic->height);
  
      void* pUBuffer = av_malloc(pic->linesize[1] * pic->height / 2);
  
      void* pVBuffer = av_malloc(pic->linesize[2] * pic->height / 2);
  
      assert(pYBuffer);
  
      assert(pUBuffer);
  
      assert(pVBuffer);
  
  
  
      pic->data[0] = (uint8_t*)pYBuffer;
  
      pic->data[1] = (uint8_t*)pUBuffer;
  
      pic->data[2] = (uint8_t*)pVBuffer;
  
      pic->buf[0] = av_buffer_create(pic->data[0], pic->linesize[0] * pic->height, our_buffer_default_free, NULL, 0);
  
      pic->buf[1] = av_buffer_create(pic->data[1], pic->linesize[1] * pic->height / 2, our_buffer_default_free, NULL, 0);
  
      pic->buf[2] = av_buffer_create(pic->data[2], pic->linesize[2] * pic->height / 2, our_buffer_default_free, NULL, 0);
  
      return 0;
  
  }

  • If I don’t hook get_buffer2 (keep ffmpeg use its own AVFrame memory allocation) and activate my multithread job system, everything is running ok ( no crash)
  • If I hook get_buffer2 with the code provided and multi-thread activated, I get some random crashs ( after few seconds or minutes, random )
  • If I hook get_buffer2 without multi-thread activated, everything is running ok (no crash)

  So it seems the way I hook "get_buffer2" is not thread safe, but I just don’t see why. ( I guess av_malloc & av_free are threadsafe on windows platform)

  Any idea ?

  PS : I don’t have many details on the crash because I’m using a pre-compiled FFMPEG. It often crash in avcodec57.dll. I’m using windows 64bits system, my app & FMMPEG binaries are both 32bits. Details about FFMPEG version used :

  Zeranoe's FFmpeg Builds Home Page: /ffmpeg.zeranoe.com/builds/>
  
  
  
  FFmpeg version: 20151103-git-6df2c94
  
    libavutil      54. 30.100 / 54. 30.100
  
    libavcodec     56. 57.100 / 56. 57.100
  
    libavformat    56. 40.101 / 56. 40.101
  
    libavdevice    56.  4.100 / 56.  4.100
  
    libavfilter     5. 32.100 /  5. 32.100
  
    libswscale      3.  1.101 /  3.  1.101
  
    libswresample   1.  2.101 /  1.  2.101
  
    libpostproc    53.  3.100 / 53.  3.100