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• Why is exec('which ffmpeg') returning nothing in my application ?

  28 avril 2015, par EchoLogic

  I’m trying to deal with FFMpeg for my application, but I’m encountering some difficulty in getting it set up. To instantiate or create an instance of FFMpeg, I need to call a create() method and pass through the operating locations of FFMpeg and FFProbe. To do this, I was hoping to be able to write :

          $ffmpeg = FFMpeg\FFMpeg::create([
  
                  'ffmpeg.binaries' => exec('which ffmpeg'),
  
                  'ffprobe.binaries' => exec('which ffprobe')
  
          ]);

  But, sadly, the command exec('which ffmpeg') returns an empty string. If I run the ’which ffmpeg’ command in Terminal, I get a response :

  /usr/local/bin/ffmpeg

  So why does it work in my terminal, but not when my PHP script tries to execute it ?

  I’ve tried a few solutions, such as appending 2>&1 to the end of the command, which did not help, running the command in shell_exec(), and placing the output in the second parameter of exec() which also did not solve my issue.

  I feel like this may be some sort of weird permissions issue...

  Addendum

  It has been brought to my attention that PHP cannot see my $PATH variable. From the console, echo $PATH produces :

  /Applications/MAMP/bin/php/php5.6.2/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:‌​/sbin:/opt/X11/bin:/usr/local/git/bin:/opt/ImageMagick/bin

  While calling the same from my application with exec() produces :

  /usr/bin:/bin:/usr/sbin:/sbin237.671000 

• 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.

• embed FFplay player in Qt application

  27 juin 2014, par Ashish

  Hello Guys,

  I want to use the FFplay player in my Qt application. I am working on Mac OS and Qt 4.7. I am using FFplay command line exe for playing video files. When i run command for playing videos in ffplay the player creates its new widget as player. i am using this command for playing videos :

  /user/local/Cellar/ffmpeg/2.2.1/bin/ffplay /users/dev/Desktop/video/1.mp4

  I want to embed that new widget on my own widgets. Can any one tell how could i do it ? your help will really appreciate.

  Thanks

  Ashish