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• How to cut and merge avi videos with java

  17 août 2017, par Monticle

  I want to cut and merge some avi videos(same codec, same resolution, same fps) using java library.

  Now I am trying this using Humble video(https://github.com/artclarke/humble-video), which is based on ffmpeg.

  I want to use the seek function to cut the input video first, but the result is not correct.

  this is my code.

  public void cutjob(String input, String output, int starttime) {
  
          final Demuxer demuxer = Demuxer.make();
  
          final Muxer muxer = Muxer.make(output, null, "avi");
  
          try {
  
              demuxer.open(input, null, false, true, null, null);
  
              final MuxerFormat format = MuxerFormat.guessFormat("avi", null, null);
  
              int n = demuxer.getNumStreams();
  
              final Decoder[] decoders = new Decoder[n];
  
              for (int i = 0; i < n; i++) {
  
                  final DemuxerStream ds = demuxer.getStream(i);
  
                  decoders[i] = ds.getDecoder();
  
                  final Decoder d = decoders[i];
  
                  if (d != null) {
  
                      if (format.getFlag(MuxerFormat.Flag.GLOBAL_HEADER))
  
                          d.setFlag(Coder.Flag.FLAG_GLOBAL_HEADER, true);
  
                      d.open(null, null);
  
                      muxer.addNewStream(d);
  
                  }
  
              }
  
              muxer.open(null, null);
  
  
  
              demuxer.seek(-1, Long.MIN_VALUE, (long)starttime* Global.getDefaultTimeBase().getDenominator(), Long.MAX_VALUE, Demuxer.SeekFlag.SEEK_ANY.swigValue());
  
              final MediaPacket packet = MediaPacket.make();
  
              long dts = -1;
  
              while (demuxer.read(packet) >= 0) {
  
                  System.out.println("dts:"+packet.getDts() + ",pts:"+packet.getPts());
  
                  final Decoder d = decoders[packet.getStreamIndex()];
  
                  if (packet.isComplete() && d != null) {
  
                      dts = dts == -1 ? packet.getDts() : dts;
  
  
  
                      packet.setDts(packet.getDts() - dts);
  
                      packet.setPosition(-1);
  
                      muxer.write(packet, false);
  
  
  
                  }
  
              }
  
              muxer.close();
  
              demuxer.close();
  
          } catch (InterruptedException e) {
  
              // TODO Auto-generated catch block
  
              e.printStackTrace();
  
          } catch (IOException e) {
  
              // TODO Auto-generated catch block
  
              e.printStackTrace();
  
          }
  
      }

  The video source is about 190 seconds long, and I set the "starttime" as 180,
  want to cut the last 10 seconds and write to a new avi file.

  The output avi file is 10 seconds long, but only the last 5s of the video is correct, the first 5s seems no data.

  Is there any wrong in my code.
  Thanks.

• How to get success info from ffmpeg on C# ?

  13 mars 2014, par user2989391

  I using ffmpeg on C#, my argument worked fine but i don't know get success handle..
  Sorry for my bad English.
  Thank you for help.

      ProcessStartInfo psi = new ProcessStartInfo("bin\\ffmpeg.exe");
  
      Process proc = Process.Start(psi);
  
      psi.UseShellExecute = false;
  
      psi.CreateNoWindow = true;
  
      psi.Arguments = " My argument ";
  
      psi.RedirectStandardError = true;
  
      psi.WindowStyle = ProcessWindowStyle.Hidden;
  
      proc = Process.Start(psi);
  
      StringBuilder sb = new StringBuilder();
  
      StreamReader outputReader = proc.StandardOutput;
  
      while (!(proc.StandardOutput.EndOfStream)) {
  
          sb.AppendLine(proc.StandardOutput.ReadLine());
  
      }
  
      proc.WaitForExit();
  
      proc.Close();
  
      psi = null;

• Using ffmpeg to create video from images - Python [duplicate]

  24 mars 2017, par Harel

  This question already has an answer here :

  • Communicate multiple times with a process without breaking the pipe ?
    
    4 answers
    

  I’m using FFMPEG in python (using this tutorial) and my main goal is to take a screenshot and append it into an existing mp4 video(append it using the encoder, not raw appending).

  That’s the code I’m using right now, this script only writes a video of one frame(the first screenshot) and doesn’t do anything with all the other screenshots.

  command = [ FFMPEG_BIN,
  
      '-f', 'rawvideo',
  
      '-codec', 'rawvideo',
  
      '-s', '1920x1080', # size of one frame
  
      '-pix_fmt', 'rgb24',
  
      '-r', '24', # frames per second
  
      '-i', '-', # The input comes from a pipe
  
      '-an', # Tells FFMPEG not to expect any audio
  
      '-vcodec', 'mpeg4',
  
      'my_output_videofile.mp4' ]
  
  
  
  for x in range(30):
  
      pipe = sp.Popen(command, stdin = sp.PIPE, stderr = sp.PIPE)
  
      im = np.array(ImageGrab.grab()).tostring()
  
      pipe.communicate(input = im)
  
      pipe.stdin.close()
  
      if pipe.stderr is not None:
  
          pipe.stderr.close()
  
      pipe.wait()

  Edit :
  Apparently using Popen.communicate breaks the pipe (Thanks to Peter Wood !).

  After fixing the pipe breaking scenario I have encountered another problem, after writing 235 frames to the video the program crashes.

  The new edited script :

  command = [ FFMPEG_BIN,
  
      '-y',
  
      '-f', 'rawvideo',
  
      '-codec', 'rawvideo',
  
      '-s', '1920x1080', # size of one frame
  
      '-pix_fmt', 'rgb24',
  
      '-r', '24', # frames per second
  
      '-i', '-', # The input comes from a pipe
  
      '-an', # Tells FFMPEG not to expect any audio
  
      '-vcodec', 'mpeg4',
  
      'my_output_videofile.mp4' ]
  
  
  
  pipe = sp.Popen(command, stdin = sp.PIPE, stderr = sp.PIPE)
  
  
  
  for x in range(300):
  
      print x
  
  
  
      im = np.array(ImageGrab.grab()).tostring()
  
      pipe.stdin.write(im)
  
      pipe.stdin.flush()