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• Saving raw YUV420P frame FFmpeg/Libav

  14 mars 2016, par Sir DrinksCoffeeALot

  Previously i successfully opened, decoded and saved frames from .mp4 file. Raw frames were in YUV420P format which i converted to RGB24 using sws_scale() function and saved them into a .ppm file. What i’m trying to do now is to keep raw decoded frames in YUV420P, or convert frames that i get to YUV420P just to make sure they are in YUV420P. But the problem is that i don’t know which type of file should i use, i’m guessing .yuv ? And another problem is that i also don’t know how to save YUV420P data.

  I used to save RGB24 in .ppmlike this :

  for (y = 0; y < height; y++)
  
  {
  
  fwrite(frame->data[0] + y*frame->linesize[0], 1, width * 3, pf);
  
  }

  which worked fine since i was using only 1 plane. But YUV420P uses 3 planes (Y,Cb,Cr). What i tried to do is to save Y component first, and Cb/Cr after that.

  for (y = 0; y < height; y++)
  
  {
  
      fwrite(frame->data[0] + y*frame->linesize[0], 1, width, pf);
  
  }
  
  
  
  for (y = 0; y < height / 2; y++)
  
  {
  
      fwrite(frame->data[1] + y*frame->linesize[1], 1, width, pf);
  
      fwrite(frame->data[2] + y*frame->linesize[2], 1, width, pf);
  
  }

  But as you can guess that is not working at all. Actually it does, but it saves only Y component. Could anyone guide me to right direction please ?

  EDIT
  I’ve changed mine saveFrame() function like you said, but instead of interleaved chroma writing i used planar. But, i’m still getting only Y component picture (black-white).

  fprintf(pf, "P5\n%d %d\n255\n", width, height);
  
  
  
  for (y = 0; y < height; y++)
  
  {
  
      fwrite(frame->data[0] + y*frame->linesize[0], 1, width, pf);
  
  }
  
  
  
  for (y = 0; y < height / 2; y++)
  
  {
  
      fwrite(frame->data[1] + y*frame->linesize[1], 1, width / 2, pf);
  
  }
  
  
  
  for (y = 0; y < height / 2; y++)
  
  {
  
      fwrite(frame->data[2] + y*frame->linesize[2], 1, width / 2, pf);
  
  }

• 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 !

• Merge commit ’65a802401c6cc136576bb2e613c0577cbf622aa8’

  17 avril 2016, par Derek Buitenhuis

  Merge commit ’65a802401c6cc136576bb2e613c0577cbf622aa8’
  * commit ’65a802401c6cc136576bb2e613c0577cbf622aa8’ :
  
    build : Add component for the SRTP common code
  Merged-by : Derek Buitenhuis <derek.buitenhuis@gmail.com>
  

  • [DH] configure
  • [DH] libavformat/Makefile