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• What are the APIs for hardware accelerated video decoding in phones ?

  11 janvier 2012, par cloudraven

  I have seen many smartphones coming with hardware accelerated video decoding supporting mpeg2 and h264, but unlike in desktop and laptop systems, it is not clear to me how to interact with the hardware acceleration.
  For desktops/laptops there is DXVA, VDPAU and OpenMax.
  Is any of those supported in Mobile phones ? I think OpenMax is, but I am not sure of how widely supported it is.

  Is anyone familiar with what is usually used to write hardware accelerated media players and decoders for platforms like Snapdragon, Tegra 2 or Omap 4 running Android or Windows Phone ?
  I know that ffmpeg can be compiled for arm and I wonder what kind of hardware video acceleration it supports on that platform.

• Extract audio amplitude from video

  11 janvier 2012, par Andrew

  I need to process >200 videos by getting several snapshots from each one.
  Each snapshot will be taken if the volume is higher than 'x'.
  So I can make snapshots with FFMPEG but I don't know how to extract the amplitude graph.
  How can I get an array with the audio volume of each frame ?

• Start/Stop Ffmpeg video capture

  2 novembre 2011, par Dasas

  I'm currently using ffmpeg for recording video from a webcam source.

  At the moment i use java to call for ffmpeg to execute.

  The code is pretty straightforward

  ffmpeg -f dshow -i video="Dualpix HD720p for Notebooks" -s cif -r 20 -f flv TEST.FLV
  
  Runtime.getRuntime().exec("rundll32 SHELL32.DLL,ShellExec_RunDLL " + cmd);

  and it works fine.

  The only real issue occour when when i need to stop the recording process.

  I know that i can press q or even ctrl+c in the CMD but i need to stop the process without keyboard input.

  That would be pretty easy to achive by killing the process but in this case ffmpeg do not finalize the video leaving me with a corrupt, need to fix, output.

  Is there any way to trigger the finalizing process "remotely".

  Thx,
  D.

  *******EDIT**********

  Thx for the prompt answer, i think you're referring to

  Process.getOutputStream()

  As for this case i have tried with this code :

  public Process doCommand(String cmd) throws Exception {
  
  
  
      rt = Runtime.getRuntime();
  
      Process proc = rt.exec(cmd);
  
      recOS= proc.getOutputStream();
  
      regcIS= proc.getInputStream();
  
  
  
      return proc;
  
  
  
  }
  
  
  
     receOS.write(("q/n".getBytes()));
  
     recOS.flush();

  I'm still getting an error, to be more specific, java.io.ioexception The pipe is being closed ...