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• FFMPEG and DXVA2

  5 février 2016, par Bobnono

  I’ve made a player for IP camera (fullHD H264) with FFMPEG
  I code under windows with Qt.I need the lowest latency as possible and the best result I can get is done whith :

  • I got the packet with live555,
  • decode with ffmpeg
  • display it with SDL.

  But with "slow" CPU I have lot of latency if the bitrate is too high or it can’t handle 1080p.

  I really want to try hardware acceleration with DXVA2 to see if I can get better performance especially in slowest CPU.

  But i really don’t know how to proceed. I have to build FFMPEG with —enable-dxva2 and —enable-hwaccel=h264_dxva2 ? or Zeranoe build
  I have never use Direct X, do I need Direct X knowledge, or ffmpeg with —enable-dxva2 and —enable-hwaccel=h264_dxva2 care of everything ?

  Thank you

  Edit :

  Hello, I use this post to help me in my HW acceleration with FFMPEG
  Failed to execute : 0x80070057, when decoding video via ffmpeg with dxva2

  I decode the packet with

  avcodec_decode_video2(pCodecCtx, pFrame, &gotPic, &packet);

  and I’m getting my decoded frame with

  dxva2_retrieve_data_call(pCodecCtx, pFrame, &gotPic, &packet);

  I tried to convert it

  sws_scale(img_convert_affic, pFrame->data, pFrame->linesize, 0, pCodecCtx->height, pFrameRGB->data, pFrameRGB->linesize);

  and copy the buffer to a Qimage

  LastFrame=QImage(w,h,QImage::Format_RGB888);
  
  for(int y=0;ydata[0]+y*pFrameRGB->linesize[0],w*3);

  I got my picture but with lot of artefact and after few seconds I got a segmentation fault in dxva2_retrieve_data_call(pCodecCtx, pFrame, &gotPic, &packet);

  Edit :
  Problem solved i didn’t check if I got a picture before retreiving it.
  But the performance are very poor on my desktop cmputer (intel core i5 650, 4GB RAM, ATI HD5800) it consumes 5% more of CPU, 3 times more RAM, and lot of corrupt frame.
  It’s better on a newer computer, but soft decoder is better.
  dxva2_retrieve_data_call and sws_swale consume lot of time when hwaccel is enabled ...

  Is there a way to display NV12 picture in Qt (no sws_scale conversion) and there is a way to optimise dxva_retrieve_data_call ?

• mpeg dash on wowza server not working, status error 404 Not Found

  10 septembre 2015, par jobin

  adaptives links for mpeg dash on wowza server not working with me, the following are the steps that I used to publish video on wowza :

  1. I install and configure Wowza server, and I tested it and it is working fine.

  2. Transcode this video using ffmepg (I bring these command from wowza documentation)

  3. I test the files and all of them workig fine then I moved these files to wowza content folder and create the smil file as following :

  

  <?xml version="1.0" encoding="UTF-8"?>
  
  <smil title="sintel">
  
    
  
      <switch>
  
        <video width="320" height="180" src="sintel_320p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="640" height="360" src="sintel_640p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="320" height="180" src="sintel_400p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="420" height="270" src="sintel_700p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="720" height="406" src="sintel_1100p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="1024" height="576" src="sintel_1300p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
        <video width="1080" height="608" src="sintel_1500p.mp4" systemlanguage="eng">
  
          
  
          
  
        </video>
  
      </switch>
  
    
  
  </smil>

  4. I use the mpd file (http://191.237.26.137:1935/vod/smil:sintel.smil/manifest.mpd) with http://www.jwplayer.com/innovation/roadmap/mpeg-dash/

  Result : the video work for first few seconds the stop

  

• Convert 720p Mp4 to 480p with php ffmpeg

  15 février, par Parm Dhillon

  I need to covert 720p or 1080p video to 480p mp4 video , i found below code

  



  ffmpeg -i input -vf scale=-1:480 -vcodec mpeg4 -qscale 3 output.mp4


  



  and please help me , i am unable to give it INPUT VIDEO ex.

  



  $video='/path/to/mp4/video';
exec('ffmpeg -i $video -vf scale=-1:480 -vcodec mpeg4 -qscale 3 output.mp4');


  



  why above code is not working