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• ffmpeg hangs when run in a multi-threaded environemt

  13 mai 2016, par Zaid Amir

  I have a service that needs to transcode large amount of videos with different formats. The service spawns five threads, one for a single video and each thread runs ffmpeg with the following command :

  ffmpeg -i %%FILEPATH%% -vf scale=X:Y -ab 128k -c:a aac -movflags faststart -strict -2 -ar 22050 -r 24 -c:v libx264 -crf 25 -y %%OUTPUT.MP4%%

  where X and Y are the desired dimensions based on the orientation of the original file basically its either 640:trunc(ow*a/2)*2 for landscape or trunc(oh*a/2)*2:640 for portrait.

  This is my ffmpeg info :

  ffmpeg version 2.4.3-1ubuntu1~trusty6 Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Nov 22 2014 17:07:19 with gcc 4.8 (Ubuntu 4.8.2-19ubuntu1)
  
    configuration: --prefix=/usr --extra-version='1ubuntu1~trusty6' --build-suffix=-ffmpeg --toolchain=hardened --extra-cflags= --extra-cxxflags= --libdir=/usr/lib/x86_64-linux-gnu --shlibdir=/usr/lib/x86_64-linux-gnu --incdir=/usr/include/x86_64-linux-gnu --enable-gpl --enable-shared --disable-stripping --enable-avresample --enable-avisynth --enable-fontconfig --enable-gnutls --enable-ladspa --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libcdio --enable-libflite --enable-libfreetype --enable-libfribidi --enable-libgme --enable-libgsm --enable-libmodplug --enable-libmp3lame --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librtmp --enable-libschroedinger --enable-libshine --enable-libspeex --enable-libssh --enable-libtheora --enable-libtwolame --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-opengl --enable-x11grab --enable-libxvid --enable-libx265 --enable-libdc1394 --enable-libiec61883 --enable-libzvbi --enable-libzmq --enable-frei0r --enable-libx264 --enable-libsoxr --enable-openal --enable-libopencv
  
    libavutil      54.  7.100 / 54.  7.100
  
    libavcodec     56.  1.100 / 56.  1.100
  
    libavformat    56.  4.101 / 56.  4.101
  
    libavdevice    56.  0.100 / 56.  0.100
  
    libavfilter     5.  1.100 /  5.  1.100
  
    libavresample   2.  1.  0 /  2.  1.  0
  
    libswscale      3.  0.100 /  3.  0.100
  
    libswresample   1.  1.100 /  1.  1.100
  
    libpostproc    53.  0.100 / 53.  0.100
  
  Hyper fast Audio and Video encoder
  
  usage: ffmpeg [options] [[infile options] -i infile]... {[outfile options] outfile}...

  The service is written in Java and running on Ubuntu Server 14.04 and the machine is an 64-bit octa-core server.

  This is the code block that executes ffmpeg :

  try 
  
  {
  
      ProcessBuilder procBuilder = null;
  
  
  
  
  
      String sArgs = String.format("ffmpeg -i %s -vf scale=%s:%s -ab 128k -c:a aac -movflags faststart -strict -2 -ar 22050 -r 24 -c:v libx264 -crf 25 -y %s",
  
                  originalPath,
  
                  outWidth,
  
                  outHeight,
  
                  targetPath
  
          );
  
  
  
      }
  
  
  
      String[] arrArgs = sArgs.split("\\s+");
  
      procBuilder = new ProcessBuilder(Arrays.asList(arrArgs));
  
      procBuilder.redirectErrorStream(true);
  
     procBuilder.redirectOutput();
  
  
  
  
  
      Process process = procBuilder.start();
  
  
  
      try (BufferedReader reader = new BufferedReader(new InputStreamReader(process.getInputStream()))) 
  
      {
  
          String line = null;
  
          while ((line = reader.readLine()) != null) 
  
          {
  
              System.out.println(line);
  
          }
  
          errorCode = process.waitFor();
  
      }
  
  }
  
  catch(Throwable ex)
  
  {
  
  }

  I am currently spawning five threads, and each thread runs a single instance of ffmpeg targeting a single video file. This works fine most of the time, but every once in a while threads start to hang. I noticed from top that ffmpeg hangs indefinitely on some files with one of the threads using 100% of the core CPU and no progress is made. It happened with different file types as I noticed this on mkv, avi, wmv and mp4 files.

  I am not sure what is causing ffmpeg to hang, it does not happen right at the beginning of the transcoding process, ffmpeg starts converting the file fine but somewhere in the middle it gets stuck.

  Now this is not a problem with the files as when I try the same command on the same file manually it runs fine. And it only seems to happen when there are multiple instances of ffmpeg running at the same time as I now changed my service to only run a single thread and it has been running for almost a month with no issues.

  Is there an option that I need to use to allow multiple instances of ffmpeg to run at the same time ? Is it something in the command line that I currently use that causes this ?

• Revision 56d048c412 : Moving mv entropy encodings calculation to the encoder side. Moved arrays : vp

  26 novembre 2013, par Dmitry Kovalev

  Changed Paths :
   Modify /vp9/common/vp9_alloccommon.c

  
   Modify /vp9/common/vp9_entropymv.c

  
   Modify /vp9/common/vp9_entropymv.h

  
   Modify /vp9/encoder/vp9_encodemv.c

  
   Modify /vp9/encoder/vp9_encodemv.h

  
   Modify /vp9/encoder/vp9_onyx_if.c

  
  
  Moving mv entropy encodings calculation to the encoder side.

  Moved arrays :
  vp9_mv_joint_encodings
  vp9_mv_class_encodings
  vp9_mv_class0_encodings
  vp9_mv_fp_encodings

  Change-Id : Iaf5008c579fcbd6d77fdd81d1aef8c71b5f308b7

• Revision 7ab9a9587b : Remove Wextra warnings from vp9_sad.c As a side-effect, the max_sad check is re

  13 mai 2014, par Deb Mukherjee

  Changed Paths :
   Modify /test/sad_test.cc

  
   Modify /vp8/common/rtcd_defs.pl

  
   Modify /vp8/common/sad_c.c

  
   Modify /vp8/common/variance.h

  
   Modify /vp8/encoder/mcomp.c

  
   Modify /vp8/encoder/rdopt.c

  
   Modify /vp9/common/vp9_rtcd_defs.pl

  
   Modify /vp9/encoder/vp9_encodeframe.c

  
   Modify /vp9/encoder/vp9_mbgraph.c

  
   Modify /vp9/encoder/vp9_mcomp.c

  
   Modify /vp9/encoder/vp9_rdopt.c

  
   Modify /vp9/encoder/vp9_sad.c

  
   Modify /vp9/encoder/vp9_variance.h

  
  
  Remove Wextra warnings from vp9_sad.c

  As a side-effect, the max_sad check is removed from the
  C-implementation of VP8, for consistency with VP9, and to
  ensure that the SAD tests common to VP8/VP9 pass.
  That will make the VP8 C implementation of sad a little slower
  but given that is rarely used in practice, the impact will be
  minimal.

  Change-Id : I7f43089fdea047fbf1862e40c21e4715c30f07ca