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• FFmpeg interlace / zoom in when launch another application

  23 avril 2017, par etang

  I’m running ffmpeg 3.3 on osx, and running into this problem :

  I’m trying to grab my webcam and stream it to a RTMP endpoint with this command

  ffmpeg -f avfoundation -framerate 30 -pixel_format uyvy422 -i "0:0" -vcodec libx264 -tune zerolatency -x264-params keyint=30:no-scenecut -f flv rtmp://localhost:1935/

  The video looks fine until I launch another application that uses the camera (say OBS or a webrtc camera application like google hangout) - at which time the picture seems to zoom into the top left corner and becomes interlaced incorrectly. Here are 2 screenshots to compare.

  

  

• Direct3d Color space conversion in GPU

  12 juin 2019, par eruslu

  Creating direct3d surface inYV12 format and rendering video frames in yuv420 format causes a blur video. Seems like there is a smog on video. I think this is because yuv 420 color space format’s data range is in 16-235 for Y planes and 16-240 for U and V planes. They are not in range of 0-255.

  I changed color format to BGRA in CPU by using ffmpeg’s sws_scale() function and I created direct3d surface in BGRA format and then displayed video is OK. But cpu consumption is very high due to color space conversion. Is there any way to make color conversion in GPU or is there another way to have sharp video display ?

  This is how I create YV12 surface

  m_pDirect3DDevice->CreateOffscreenPlainSurface(_srcWidth, _srcHeight, (D3DFORMAT)MAKEFOURCC('Y', 'V', '1', '2'), D3DPOOL_DEFAULT, &m_pDirect3DSurfaceRender, NULL);

  Here I copy yuv planes of camera’s video frames data to direct3d surface

          BYTE* pict = (BYTE*)d3d_rect.pBits;
  
          BYTE* Y = pY;
  
          BYTE* V = pV;
  
          BYTE* U = pU;
  
  
  
          for (int y = 0; y < _srcHeight; y++)
  
          {
  
              memcpy(pict, Y, p1);
  
              pict += d3d_rect.Pitch;
  
              Y += p1;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, V, p3);
  
              pict += d3d_rect.Pitch >> 1;
  
              V += p3;
  
          }
  
          for (int y = 0; y < _srcHeight >> 1; y++)
  
          {
  
              memcpy(pict, U, p2);
  
              pict += d3d_rect.Pitch >> 1;
  
              U += p2;
  
          }

  I appreciate your help, thank you.

• Killing infinite ffmpeg on the command line from an application

  14 décembre 2013, par bhupinder

  I am using

  ffmpeg.exe -f dshow -i audio=virtual-audio-capturer -q 4 -y -tune zerolatency outfile.mp3

  to grap sound from speakers. This command runs infinitely. I have to use

  Process->kill();

  command to stop execution of this command in my application.

  I want to know if it is safe to kill it the way I am killing, or is there any better way ?