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• Executing process on cmd, does not process

  2 août 2012, par Z Jackobovski

  I am running ffmpeg from Java. Using it to convert flv files to mp3.

  When I run the code below, ffmpeg starts, creates a new file (the .mp3 one) but runs at 0% of CPU. When I stop the JAVA app (from netbeans) ffmpeg remains open and goes from 0% to 99% per Windows task manager (CTRL-ALT-DEL). Another weird thing is going on. The output from ffmpeg is not being printed.

  The thread is starting but for some reason java is not giving it any time to do its processing.

  Any suggestions on how to fix this ? Thanks.

  public class ConverterThread extends Thread {
  
  
  
   String fileToConvert;
  
   String fileToCreate;
  
   GetSong getSong;
  
  
  
  
  
  
  
  public ConverterThread(String downloadLocationOnDisk, GetSong getSong) {
  
     this.fileToConvert = downloadLocationOnDisk;
  
     this.getSong = getSong;
  
  }
  
  
  
  
  
  public void run(){
  
      try {
  
          Thread cur=Thread.currentThread();
  
          cur.setPriority(Thread.MAX_PRIORITY);
  
  
  
             String downloadLocationOnDisk = fileToConvert;
  
  
  
              if(downloadLocationOnDisk.contains(".flv"))
  
                  fileToCreate = downloadLocationOnDisk.replace(".flv", ".mp3");
  
  
  
              if(downloadLocationOnDisk.contains(".m4a"))
  
                  fileToCreate = downloadLocationOnDisk.replace(".m4a", ".mp3");
  
  
  
  
  
  
  
              String cmdLine =  "ffmpeg/bin/ffmpeg -i \"" + fileToConvert + "\" \"" + fileToCreate +"\""; 
  
  
  
              System.err.println(cmdLine);
  
  
  
               // run the Unix "ps -ef" command
  
               // using the Runtime exec method:
  
               Process p = Runtime.getRuntime().exec(cmdLine);
  
  
  
  
  
               BufferedReader stdInput = new BufferedReader(new 
  
                    InputStreamReader(p.getInputStream()));
  
  
  
               BufferedReader stdError = new BufferedReader(new 
  
                    InputStreamReader(p.getErrorStream()));
  
  
  
               String s;
  
  
  
               // read the output from the command
  
               while ((s = stdInput.readLine()) != null) {
  
                   System.out.println(s);
  
               }
  
  
  
               // read any errors from the attempted command
  
               System.out.println("Here is the standard error of the command (if any):\n");
  
               while ((s = stdError.readLine()) != null) {
  
                   System.out.println(s);
  
               }
  
  
  
      } catch (IOException ex) {
  
          Logger.getLogger(ConverterThread.class.getName()).log(Level.SEVERE, null, ex);
  
      }

• Creating MOV from PNGs with ffmpeg : playback issue in older quicktime (7.6.6)

  15 avril 2013, par Jim Lindstrom

  I'm using ffmpeg to create a MOV file from a series of images. When I view the movie in Quicktime 7.7.x, it looks great (left image). When I view in Quicktime 7.6.6 I get this weird issue (on the right) :

  
  

  Any idea even what this is, much less how to fix it ?

  Details

  My source images are a mix of PNGs and JPGs that I pre-process with ImageMagick (to draw text, captions, etc). I store intermediate results as MPCs, and final frames as PNMs.

  To draw the above frame, I'm doing this :

  convert -background none -fill white -font my_font.ttf -pointsize 132 -gravity \
  
          center -size 945x550 caption:"Stills Demo" background-template.png     \
  
          +swap -composite -resize 1920x1080! /tmp/title_screen4338355.png
  
  convert -auto-orient /tmp/title_screen4338355.png -resize 100% -type TrueColor \
  
          /tmp/1b2764754ce6e420986ed74b942bcf67.mpc
  
  convert /tmp/1b2764754ce6e420986ed74b942bcf67.mpc -set option:distort:viewport \
  
          1920x1080+0+0  +distort SRT '960.0,540.0 1.0 0 960.0,540.0'            \
  
          /tmp/stills-project-6224/video_frames/img_0000.pnm

  I render frames with ffmpeg like so :

  ffmpeg -y -f image2 -i /tmp/stills-project-6224/video_frames/img_%04d.pnm      \
  
         -i /tmp/soundtrack_8702693.wav -vcodec libx264 -pix_fmt yuvj444p        \
  
         -b:v 2200k  -r 25 -strict experimental                                  \
  
         /tmp/stills-project-6224/video_rendered/output.mov

  The rest of the video is fine. The other images are photos (jpgs or pngs) that I process in the same way. I have also noticed that if I don't apply text to this background-template, the image shows up fine, so I think the issue has something to do with either how I'm processing or saving that image.

• Issue with MJPEG stream playback speed when encoding with FFmpeg

  6 janvier, par Arciiix

  I'm working with a MJPEG stream source

  


  Stream #0:0: Video: mjpeg (Baseline), yuvj420p(pc, bt470bg/unknown/unknown), 1280x720 [SAR 1:1 DAR 16:9], 25 tbr, 25 tbn

  


  I want to capture this stream and save it to an MP4 file using FFmpeg, but I am running into a weird issue.

  


  The only way it works fine is when I just copy the stream without reencoding and using wallclock as timestamps (cmd 1) :

  


  ffmpeg -use_wallclock_as_timestamps 1 -i "http://IP/video/1280x720" -c:v copy output_good.mp4


  


  However, when I try encoding the stream with libx264, the playback speed of the resulting video becomes slower than 100%, causing the video to gradually fall out of sync with real-time. This happens even when I use any encoding, also when I explicitly set the frame rate or vsync. For example, these commands fail :

  


  

  • CMD 2 : ffmpeg -i "http://IP/video/1280x720" -c:v libx264 -r 30 -preset fast output_bad1.mp4

  


  • CMD 3 : ffmpeg -use_wallclock_as_timestamps 1 -i "http://IP/video/1280x720" -c:v libx264 output.mp4

  


  


  https://www.youtube.com/watch?v=PF0fuCu7Xao

  


  As you can see in the comparison of the resulting videos, the playback gradually slows down with CMD 2 and CMD 3, while it's alright with CMD 1.

  


  What I've noticed is that on the FFmpeg stdout, when using encoding, the speed= and FPS= go up and up, e.g. to 31 FPS even though my source is technically at 25 FPS.

  


  What I've tried :

  


  

  • different encoding codecs (e.g. libvpx)

  


  • -re

  


  • preset ultrafast on encoding

  


  • vsync (fps_mode), both ctr and vfr

  


  • fps=30 filter

  


  


  Has anyone encountered a similar issue or know how to force FFmpeg to preserve the correct playback speed while encoding or enforcing a frame rate ? Thanks !