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• FFmpeg-split.py can't determine video length

  13 juin 2017, par Almog Woldenberg

  First, I’m not a developer. I’m trying to split a movie into 1 minute clips usinf ffmpeg-split.py python script. I made sure FFmpeg is installed it trying a simple command and it worked like magic :

  ffmpeg -i soccer.mp4 -ss 00:00:00 -codec copy -t 10 soccer1.mp4

  A new video file was created in the same folder.

  I saved the FFmpeg-split.py in the same dir, updated python PATH and typed the following command :

  python ffmpeg-split.py -f soccer.mp4 -s 10

  what I got back was :

  can't determine video length

  I believe it just can’t find the file. I switched video files and even deleted it and got the same message.

  Any ideas ?

• How to determine when FFmpeg process completes

  18 avril 2017, par ajbeaven

  var origFilePath = "C:/MyOriginalFile.webm";
  
  var processedFilePath = "C:/MyProcessedFile.webm";
  
  
  
  RunFfmpeg($"-i \"{origFilePath}\" -af \"silenceremove=1:0.1:0.001, areverse, silenceremove=1:0.1:0.001, areverse\" \"{processedFilePath}\" -y");
  
  
  
  // fails with IOException as the file presumably not been released by FFmpeg
  
  System.IO.File.Delete(origFilePath);

  When the file is deleted, the following exception is frequently (maybe 80% of the time) thrown :

  IOException : The process cannot access the file ’C :\MyOriginalFile.webm’ because it is being used by another process.

  The call to create and run the FFmpeg process goes like this :

  private List<string> RunFfmpeg(string arguments)
  
  {
  
      using (var process = new Process())
  
      {
  
          process.StartInfo.RedirectStandardOutput = true;
  
          process.StartInfo.RedirectStandardError = true;
  
          process.StartInfo.FileName = _hostingEnvironment.ContentRootPath + _settings.FfmpegPath;
  
          process.StartInfo.Arguments = arguments;
  
          process.StartInfo.UseShellExecute = false;
  
          process.StartInfo.CreateNoWindow = true;
  
  
  
          // ffmpeg only uses strerr for its output
  
          var output = new List<string>();
  
          process.ErrorDataReceived += new DataReceivedEventHandler((s, e) => { 
  
              if (e.Data != null)
  
                  output.Add(e.Data);
  
          });
  
  
  
          process.Start();
  
          process.BeginErrorReadLine();
  
          process.WaitForExit();
  
          return output;
  
      }
  
  }
  
  </string></string>

  It appears that even though the process has completed when the file is deleted, FFmpeg is still processing or has otherwise not released it.

  Is this behaviour expected ? How do I go about ensuring that FFmpeg has finished processing the files before continuing ?

• ffmpeg : how to determine frame rate automatically ?

  25 décembre 2016, par mrgloom

  I use this simple script to convert video to images using ffmpeg, but frame rate is fixed, how can I determine it automatically ?

  FRAME_RATE="30"
  
  SEPARATOR='/'
  
  
  
  
  
  VIDEO_PATH=$1
  
  
  
  VIDEO_BASE_DIR=`dirname $1`
  
  FRAMES_DIR=$VIDEO_BASE_DIR$SEPARATOR"Frames"
  
  rm -rf $FRAMES_DIR
  
  mkdir $FRAMES_DIR
  
  
  
  #Convert video to images
  
  ./ffmpeg -r $FRAME_RATE -i $VIDEO_PATH $FRAMES_DIR$SEPARATOR"image%d.png"

  UPDATE :

  By ffprobe I checked that my 1st video frame rate is 30.
  Also results are the same (339 frames are produced) even I reduce frame rate, so -r option doesn’t work or work in some other way ?

  These command give the same result :

  ./ffmpeg -r 10 -i $VIDEO_PATH $FRAMES_DIR$SEPARATOR"image%d"$EXTENSION
  
  ./ffmpeg -r 30 -i $VIDEO_PATH $FRAMES_DIR$SEPARATOR"image%d"$EXTENSION
  
  ./ffmpeg -i $VIDEO_PATH $FRAMES_DIR$SEPARATOR"image%d"$EXTENSION

  Output :

  ffmpeg version N-63893-gc69defd Copyright (c) 2000-2014 the FFmpeg developers
  
    built on Jul 16 2014 05:38:01 with gcc 4.6 (Debian 4.6.3-1)
  
    configuration: --prefix=/root/ffmpeg-static/64bit --extra-cflags='-I/root/ffmpeg-static/64bit/include -static' --extra-ldflags='-L/root/ffmpeg-static/64bit/lib -static' --extra-libs='-lxml2 -lexpat -lfreetype' --enable-static --disable-shared --disable-ffserver --disable-doc --enable-bzlib --enable-zlib --enable-postproc --enable-runtime-cpudetect --enable-libx264 --enable-gpl --enable-libtheora --enable-libvorbis --enable-libmp3lame --enable-gray --enable-libass --enable-libfreetype --enable-libopenjpeg --enable-libspeex --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-version3 --enable-libvpx
  
    libavutil      52. 89.100 / 52. 89.100
  
    libavcodec     55. 66.101 / 55. 66.101
  
    libavformat    55. 43.100 / 55. 43.100
  
    libavdevice    55. 13.101 / 55. 13.101
  
    libavfilter     4.  8.100 /  4.  8.100
  
    libswscale      2.  6.100 /  2.  6.100
  
    libswresample   0. 19.100 /  0. 19.100
  
    libpostproc    52.  3.100 / 52.  3.100
  
  Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/home/user/myvideo1.mp4':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      creation_time   : 2016-01-16 05:30:03
  
    Duration: 00:00:11.33, start: 0.000000, bitrate: 4659 kb/s
  
      Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 640x480, 4539 kb/s, SAR 65536:65536 DAR 4:3, 30 fps, 30 tbr, 90k tbn, 180k tbc (default)
  
      Metadata:
  
        rotate          : 90
  
        creation_time   : 2016-01-16 05:30:03
  
        handler_name    : VideoHandle
  
      Stream #0:1(eng): Audio: aac (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
  
      Metadata:
  
        creation_time   : 2016-01-16 05:30:03
  
        handler_name    : SoundHandle
  
  Output #0, image2, to '/home/user/Frames/image%d.png':
  
    Metadata:
  
      major_brand     : mp42
  
      minor_version   : 0
  
      compatible_brands: isommp42
  
      encoder         : Lavf55.43.100
  
      Stream #0:0(eng): Video: png, rgb24, 640x480 [SAR 1:1 DAR 4:3], q=2-31, 200 kb/s, 30 fps, 90k tbn, 30 tbc (default)
  
      Metadata:
  
        rotate          : 90
  
        creation_time   : 2016-01-12 05:38:03
  
        handler_name    : VideoHandle
  
        encoder         : Lavc55.66.101 png
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (h264 (native) -> png (png))
  
  Press [q] to stop, [?] for help
  
  frame=  339 fps= 68 q=0.0 Lsize=N/A time=00:00:11.30 bitrate=N/A    
  
  video:195852kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown