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• Using FFMpeg with Runtime.exec() to do a simple transcoding

  1er novembre 2011, par Adam Ingmansson

  I know there are many questions touching this subject, but none have helped me solve my issue.

  Purpose :

  Transcoding a video taken,from a queue, from .mov to h.264 (for now only that)

  Solution :

  Building a java application that gets the next in the queue, transcodes it then repeat

  Problem :

  Running ffmpeg using Runtime.exec() is not working.
  Im using the StreamGobbler from this tutorial to capturing the output from the process.

  This code shows how i start my process :

  String[] command = new String[]{"./ffmpeg/ffmpeg","-i",videoFile.getPath(),"-vcodec","libx264","-fpre",preset,folder + recID + ".flv"};
  
  System.out.println("Running command..");
  
  Process p = r.exec(command);
  
  
  
   // any error message?
  
  StreamGobbler errorGobbler = new 
  
  StreamGobbler(p.getErrorStream(), "ERROR");            
  
  
  
  // any output?
  
  StreamGobbler outputGobbler = new 
  
  StreamGobbler(p.getInputStream(), "OUT");
  
  
  
  // kick them off
  
  errorGobbler.start();
  
  outputGobbler.start();
  
  
  
  //logProcessOutputAndErrors(p);
  
  
  
  int res = p.waitFor();
  
  if (res != 0) {
  
      throw new Exception("Encoding error: "+String.valueOf(res));
  
  }

  and this is the current modified version of StreamGobbler (the important part)

  InputStreamReader isr = new InputStreamReader(is);
  
  BufferedReader br = new BufferedReader(isr);
  
  String line=null;
  
  int c = 0;
  
  StringBuilder str = new StringBuilder();
  
  
  
  while (true) {
  
      c = br.read();
  
  }

  Sometimes ffmpeg just stalls, maybe waiting for my input (although there is no indication on screen).

  Sometimes it just ends.

  Sometimes (when I added the line "System.out.print((char) c) ;" in the while-loop above) i got loads of "¿¿ï" repeated over and over again, wich might be the actual encoding of the video wich I managed to capture instead of to a file.

  For those who wonders why i dont just go with a commandline or maybe even php :

  The purpose is an application that will run 24/7 transcoding anything and everything from a queue. The files are pretty large to begin with and takes about 15 min to transcode.

• Revision d435148fe6 : Enable adaptive motion search for ARF coding This commit turns on adaptive moti

  5 septembre 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_rd.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Enable adaptive motion search for ARF coding

  This commit turns on adaptive motion search for ARF coding, in
  addition to other normal inter frame coding. It improves the
  average compression efficiency :

  stdhd 0.1%
  derf 0.04%

  For the test sequences, the speed 3 runtime is reduced :

  pedestrian 1080p 2000 kbps, 149932 ms -> 144580 ms, (3.3% speed-up)
  bus CIF 1000 kbps, 8050 ms -> 7895 ms, (1.9%)
  highway CIF 100 bkps, 45033 ms -> 44078 ms, (2.2%)

  Change-Id : I5228565b609f99e8ae04f6140a2bf2b64a831d21

• Revision 33176fef87 : Skip comp inter mode tests for arf coding This commit skips the compound inter

  2 septembre 2014, par Jingning Han

  Changed Paths :
   Modify /vp9/encoder/vp9_rdopt.c

  
  
  Skip comp inter mode tests for arf coding

  This commit skips the compound inter mode prediction check in the
  rate-distortion optimization loop for ARF coding. It reduces the
  runtime for certain test clips at speed 3, at no compression
  performance change :

  bus CIF 1000 kbps, 8260 ms -> 8090 ms, 1.8% speed-up
  stockholm 720p 1000 kbps, 74453 ms -> 71826 ms, 2.9% speed-up

  No visible speed-up for pedestrian area 1080p at 2000 kbps.

  Change-Id : Ic68aa56837159b726563b784e2e3729e846465ad