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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.

• FFMPEG - Scale video filter not providing expected results

  11 novembre 2011, par dpassera

  Apologies if this question has been asked. I couldn't find it, but if it has, please let me know and I'll close this out.

  I'm attempting a simple scale of a video whose original dimensions are 480x360 and whose target dimensions are 400x300. The video starts as an FLV and eventually needs to end up as an MPEG. I'm using the following command line to do this :

  ffmpeg -i user.flv -vf "scale=400:300" user_scaled.mpg

  When I play the scaled video in MPEG Streamclip, the scale is correct and the video info shows that the dimensions are 400x300. However, when I play the scaled video in Quicktime, the video is scaled to 478x359. More importantly, FFMPEG, itself, treats the video as being 478x359, so any future commands (trimming, conversion, overlaying, etc) executed on it result in a video of 478x359.

  The initial workflow required an FLV to MPEG conversion, but I've tried this with several different in and out formats (FLV -> FLV, FLV -> MPEG, MPEG -> MPEG, etc) all with the same results. As long as I can end up with an MPEG, though, I can deal with however many steps and conversions it would take to get this scaling working.

  I'll paste the command-line output below, and a sample input video is also linked below, if you'd like it. Thank you very much for any help.

  http://www.monkeydriver.com/dpassera/stack_flv.zip

  Command-line output :

  ffmpeg -i user.flv -vf "scale=400:300" user_scaled.mpg
  
  
  
  ffmpeg version 0.7-rc1, Copyright (c) 2000-2011 the FFmpeg developers
  
    built on May 21 2011 22:13:19 with gcc 4.1.2 20080704 (Red Hat 4.1.2-50)
  
    configuration: --prefix=/usr --libdir=/usr/lib64 --shlibdir=/usr/lib64 
  
   --mandir=/usr/share/man --incdir=/usr/include --disable-avisynth
  
   --extra-cflags='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions
  
   -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic -fPIC'
  
   --enable-avfilter --enable-libdirac --enable-libgsm --enable-libmp3lame
  
   --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libx264
  
   --enable-gpl --enable-postproc --enable-pthreads --enable-shared
  
   --enable-swscale --enable-vdpau --enable-version3 --enable-x11grab
  
   --disable-yasm --enable-filters --enable-filter=movie
  
  
  
    libavutil    50. 40. 1 / 50. 40. 1
  
    libavcodec   52.120. 0 / 52.120. 0
  
    libavformat  52.108. 0 / 52.108. 0
  
    libavdevice  52.  4. 0 / 52.  4. 0
  
    libavfilter   1. 77. 0 /  1. 77. 0
  
    libswscale    0. 13. 0 /  0. 13. 0
  
    libpostproc  51.  2. 0 / 51.  2. 0
  
  
  
  [flv @ 0x11dd3b30] Estimating duration from bitrate, this may be inaccurate
  
  Input #0, flv, from 'user.flv':
  
  
  
    Metadata:
  
      duration        : 5
  
      videocodecid    : 2
  
      audiocodecid    : 6
  
      canSeekToEnd    : true
  
      createdby       : FMS 4.0
  
      creationdate    : Mon Oct 31 11:43:44 2011
  
  
  
    Duration: 00:00:04.62, start: 0.000000, bitrate: N/A
  
      Stream #0.0: Video: flv, yuv420p, 640x480, 1k tbr, 1k tbn, 1k tbc
  
      Stream #0.1: Audio: nellymoser, 44100 Hz, mono, s16
  
  
  
  [buffer @ 0x11ddc950] w:640 h:480 pixfmt:yuv420p
  
  
  
  [scale @ 0x11dda610] w:640 h:480 fmt:yuv420p -> w:400 h:300 fmt:yuv420p flags:0xa0000004
  
  
  
  [mpeg @ 0x11dd6bd0] VBV buffer size not set, muxing may fail
  
  
  
  Output #0, mpeg, to 'user_scaled.mpg':
  
    Metadata:
  
      duration        : 5
  
      videocodecid    : 2
  
      audiocodecid    : 6
  
      canSeekToEnd    : true
  
      createdby       : FMS 4.0
  
      creationdate    : Mon Oct 31 11:43:44 2011
  
      encoder         : Lavf52.108.0
  
  
  
      Stream #0.0: Video: mpeg1video, yuv420p, 400x300, q=2-31, 200 kb/s, 90k tbn, 60 tbc
  
  
  
      Stream #0.1: Audio: mp2, 44100 Hz, mono, s16, 64 kb/s
  
  
  
  Stream mapping:
  
  Stream #0.0 -> #0.0
  
  Stream #0.1 -> #0.1
  
  
  
  Press [q] to stop encoding
  
  frame=  230 fps=  0 q=10.2 size=     366kB time=3.82 bitrate= 785.6kbits/s dup=175 drop=0 
  
  frame=  267 fps=  0 q=10.7 Lsize=     412kB time=4.43 bitrate= 761.3kbits/s dup=203 drop=0    
  
  
  
  video:370kB audio:36kB global headers:0kB muxing overhead 1.568959%

• Revision 56fa3ab886 : Use non-zero mode threshold for NEARESTMV modes This commit makes the encoder t

  16 septembre 2014, par Jingning Han

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

  
  
  Use non-zero mode threshold for NEARESTMV modes

  This commit makes the encoder to use non-zero mode threshold for
  NEARESTMV modes. The runtime for test clips of speed 3 is reduced
  by about 1%.

  pedestrian 1080p 2000 kbps, 143239 ms -> 141989 ms
  bus CIF 1000 kbps, 7835 ms -> 7749 ms

  The compression performance change is about -0.02% for both derf
  and stdhd.

  Change-Id : Ib71808922c41ae2997100cb7c561f68dcebfa08e