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• ffmpeg run from shell runs properly, but does not when called from within .NET

  2 juillet 2013, par Bevin

  I'm attempting to use ffmpeg (compiled on Windows with Cygwin) in a C# program, by using the Process class to spawn an ffmpeg instance. However, I've hit a rather odd bug that doesn't make much sense.

  When I run ffmpeg directly from a shell (be it Cygwin's bash, PowerShell, cmd), ffmpeg can properly decode and reencode files without any issues :

  PS C:\audio> ffmpeg -i .\sound1.wav -acodec libvorbis -f ogg abc.ogg
  
  ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Apr  8 2013 15:10:40 with gcc 4.5.3 (GCC)
  
    configuration: --disable-encoder=vorbis --enable-libvorbis
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  [wav @ 0x800538a0] max_analyze_duration 5000000 reached at 5015510 microseconds
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
  Input #0, wav, from '.\sound1.wav':
  
    Metadata:
  
      encoder         : Lavf54.63.104
  
    Duration: 00:00:05.76, bitrate: 1411 kb/s
  
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  Output #0, ogg, to 'abc.ogg':
  
    Metadata:
  
      encoder         : Lavf54.63.104
  
      Stream #0:0: Audio: vorbis, 44100 Hz, stereo, fltp
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (pcm_s16le -> libvorbis)
  
  Press [q] to stop, [?] for help
  
  size=      55kB time=00:00:05.74 bitrate=  78.5kbits/s
  
  video:0kB audio:51kB subtitle:0 global headers:4kB muxing overhead 0.817473%

  The file plays fine, and I can encode to WAV or any other format I like. However, when I call ffmpeg from C# with the following code :

  string tempfile = Path.GetTempFileName();
  
  FileStream tempfilestr = File.OpenWrite(tempfile);
  
  input.CopyTo(tempfilestr);
  
  
  
  ProcessStartInfo pstart = new ProcessStartInfo("ffmpeg", string.Format("-i \"{0}\" -v verbose -y -f wav -", tempfile));
  
  pstart.CreateNoWindow = true;
  
  pstart.ErrorDialog = false;
  
  pstart.RedirectStandardOutput = true;
  
  pstart.RedirectStandardError = true;
  
  pstart.UseShellExecute = false;
  
  
  
  
  
  Process proc = new Process();
  
  proc.StartInfo = pstart;
  
  proc.Start();
  
  StreamReader stdout = proc.StandardOutput;
  
  StreamReader stderr = proc.StandardError;
  
  
  
  outtempfilestr = File.OpenRead(outtempfile);
  
  MemoryStream output = new MemoryStream();
  
  
  
  stdout.BaseStream.CopyTo(output);
  
  
  
  try {
  
      proc.Kill();
  
  }
  
  catch(InvalidOperationException) { }
  
  catch(Win32Exception) { }
  
  
  
  File.Delete(tempfile);
  
  
  
  return output.ToArray();

  This randomly produces errors in the output :

  ffmpeg version 1.2 Copyright (c) 2000-2013 the FFmpeg developers
  
    built on Apr  8 2013 15:10:40 with gcc 4.5.3 (GCC)
  
    configuration: --disable-encoder=vorbis --enable-libvorbis
  
    libavutil      52. 18.100 / 52. 18.100
  
    libavcodec     54. 92.100 / 54. 92.100
  
    libavformat    54. 63.104 / 54. 63.104
  
    libavdevice    54.  3.103 / 54.  3.103
  
    libavfilter     3. 42.103 /  3. 42.103
  
    libswscale      2.  2.100 /  2.  2.100
  
    libswresample   0. 17.102 /  0. 17.102
  
  [wav @ 0x80053860] parser not found for codec pcm_s16le, packets or times may be invalid.
  
      Last message repeated 1 times
  
  [wav @ 0x80053860] max_analyze_duration 5000000 reached at 5015510 microseconds
  
  Guessed Channel Layout for  Input Stream #0.0 : stereo
  
  Input #0, wav, from 'C:\Users\Bevin\AppData\Local\Temp\tmp1CCE.tmp':
  
    Duration: 00:00:05.20, bitrate: 1411 kb/s
  
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  [graph 0 input from stream 0:0 @ 0x8011f320] tb:1/44100 samplefmt:s16 samplerate:44100 chlayout:0x3
  
  Output #0, wav, to 'pipe:':
  
    Metadata:
  
      ISFT            : Lavf54.63.104
  
      Stream #0:0: Audio: pcm_s16le ([1][0][0][0] / 0x0001), 44100 Hz, stereo, s16, 1411 kb/s
  
  Stream mapping:
  
    Stream #0:0 -> #0:0 (pcm_s16le -> pcm_s16le)
  
  Press [q] to stop, [?] for help
  
  Multiple frames in a packet from stream 0
  
  [pcm_s16le @ 0x8005c160] Invalid PCM packet, data has size 3 but at least a size of 4 was expected
  
  Error while decoding stream #0:0: Invalid data found when processing input
  
  No more output streams to write to, finishing.
  
  size=     896kB time=00:00:05.20 bitrate=1411.3kbits/s    
  
  video:0kB audio:896kB subtitle:0 global headers:0kB muxing overhead 0.008719%

  Note that these errors don't always occur. Sometimes they happen for certain files, sometimes they don't. I've tried various combinations of stream redirects and temp files, none of them work. I've also verified the integrity of the temp files, and it all checks out. I've even extracted the temp file before it was deleted, and decoded it in shell without a hitch.

  Any ideas ?

  Edit : I've tried running ffmpeg from a shell script that's run through C#. It gives the same issues. Compiling ffmpeg via MinGW gives the same issue as well.

• IE9+ not playing portait video in HTML5 video tag

  12 avril 2013, par ptrn

  For some reason I can't get IE9/10 to play video that is taller than wide, when using HTML5 video tags.

  Demo :
  http://s.l6.no/demo/video+html5/

  The demo shows one video scaled down from 1280x720, which plays perfectly fine in all tested browsers, and one video scaled down from 720x1280 which plays for all browsers but IE9/10.

  Tested and works for :

  • Chrome 26, Windows 7 64-bit
  • Chromium 24, Ubuntu 64-bit
  • Firefox 14, Windows 7 64-bit

  Tested and does not work for :

  • Internet Explorer 9, Windows 7 64-bit
  • Internet Explorer 10, Windows 7 64-bit

  I'm using FFmpeg to code the videos to MP4(x264) and WebM(VP8), with the current command dummed down to this :

  ffmpeg -i in.mp4 -vcodec libx264 -pix_fmt yuv420p -y -b:v 4000k out.mp4

  The lack of profile settings would be my first point, but since the other video is playing just fine, I can't see why it should matter.

  Any ideas ?

  Edit : soft rotating the video isn't really an option, as the user is to be able to download the video to play offline. I could transcode an extra version just for IE, but come on, there's gotta be another way, no ?

• ffmpeg - Stream multiple files over an ffserver to one ffplay at different times ? [closed]

  13 mai 2013, par golmschenk

  I have an ffserver up and running. Using this server I can run a simple ffplay command :

  ffplay udp://localhost:7777

  which then waits for a stream. Then if I stream something to the server with a simple ffmpeg command :

  ffmpeg -re -i small.mp4 -f mpegts udp://localhost:7777

  The video pops up and plays fine. However, after the video is finished and the ffplay is still waiting open with the display window showing the last frame of the video just sent, then if I try to run the same ffmpeg command again to play the video again, the ffplay gets a bunch of warnings which look similar to :

  [mpegts @ 0x7fde1c0008c0] Continuity check failed for pid 256 expected 2 got 0

  And there is no playback. I would like to be able to stream one video, leave the same ffplay open and a little while after the first video has stopped stream another video. Is there a way I can achieve this ? Thank you much !