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• Command does not complete when executed through a .NET Process ?

  7 mai 2014, par Abe Miessler

  I am using ffmpeg to convert audio files. If I do it through the command line like so :

  ffmpeg -i sourceAudio.wma -f mp3 destAudio.mp3

  it works fine. But when I attempt to do the same thing in a .net application using a Process, ffmpeg starts (and is visible as a running process in my task manager), but never completes. My .NET code never executes past the "WaitForExit" portion unless I go into my task manager and kill the process manually. Code :

  using(Process process = new Process())
  
  {
  
      process.StartInfo.RedirectStandardOutput = true;
  
      //process.StartInfo.RedirectStandardError = true;
  
      process.StartInfo.FileName = Path.GetDirectoryName(System.Diagnostics.Process.GetCurrentProcess().MainModule.FileName) + @"\ffmpeg.exe";
  
      File.Copy(OrigFilePath, LocalFileName, true);
  
      System.Diagnostics.EventLog.WriteEntry("ASP.NET 2.0.50727.0", "Copied file from: " + OrigFilePath + System.Environment.NewLine + "to: " + LocalFileName);
  
      process.StartInfo.Arguments = String.Format(@"-i ""{0}"" -f mp3 ""{1}""", 
  
                                      LocalFileName, 
  
                                      tempDirectory + NewFileName);
  
  
  
  
  
      process.StartInfo.UseShellExecute = false;
  
      process.StartInfo.CreateNoWindow = false;
  
      process.Start();
  
      System.Diagnostics.EventLog.WriteEntry("ASP.NET 2.0.50727.0", "After start...");
  
      string output =  process.StandardOutput.ReadToEnd() + System.Environment.NewLine + process.StandardError.ReadToEnd();
  
      process.WaitForExit();  //<------------------------------ stalls here
  
      System.Diagnostics.EventLog.WriteEntry("ASP.NET 2.0.50727.0", "Conversion completed!  Copying file from: " + LocalConvertedFile + System.Environment.NewLine + OrigFileFolder + "\\" + NewFileName);
  
  
  
      File.Copy(LocalConvertedFile, OrigFileFolder + "\\" + NewFileName,true);
  
      File.Delete(LocalFileName);
  
      File.Delete(LocalConvertedFile);
  
      sw.Stop();
  
      System.Diagnostics.EventLog.WriteEntry("ASP.NET 2.0.50727.0", "Conversion complete. Elapsed time in seconds: " + sw.ElapsedMilliseconds/1000);
  
      return true;
  
  }

  Does anyone know why the process isn’t exiting like it does in the command line ?

• HTML5 Video Compatibility (MP4, WEBM, OGG) in 2021

  19 juillet 2021, par William

  The support of HTML5 video has evolved a lot over the years. I am trying to understand whether the <video></video> element still needs to have three sources : MP4, WEBM, and OGG.

  


  There are a lot of answers throughout StackOverflow with deeply conflicting information - some of which say that you just need MP4 now, others say, MP4 and WEBM are enough, and then finally many say that you need all three (although many of those article are 10 years old).

  


  W3 suggests that either MP4 or WEBM alone would have universal support (Even though I found a 2011 article from Google saying that they would be removing support for MP4/H.264). Wikipedia paints a more complicated picture (as well as listing that Google Chrome does indeed support MP4/H.264). Azure Media services ONLY seems to allow output in MP4, which would suggest to me that MP4 must have widespread compatibility.

  


  Also see Example 1, Example 2, Example 3.

  


  Is there any definitive information on what video types to include in an HTML5 video player to achieve widespread compatibility ?

  


  Background : I am building a Content Management Platform that allows uploading videos. When a new video is uploaded, a conversion process kicks off to convert the video into the required formats. This takes time and CPU/Memory, so if it is possible I would like to convert uploaded videos into as few formats as possible.

  


  p.s. This question HAS been asked before, however, the fundamentals of playing video on the web continually evolve and most of the answers out there have become irrelevant.

  


• WMA Lossless and ProRes Encoder

  4 mars 2012, par Multimedia Mike — General

  The projects (FFmpeg / Libav) just got a WMA lossless decoder. For those keeping score, this means that there are open source methods for decoding every single one of Microsoft’s proprietary audio codecs (Windows Media Audio, or WMA) : WMA v1, WMA v2, WMA9/Pro, WMA Voice, and now WMA lossless. Currently, it’s only advertised to decode 16-bit audio (no 24-bit). Also, when I first tried it a few days ago, it didn’t decode the very end of the single sample file I concocted many years ago (luckynight.wma). But that might be cleared up by now.

  Some other recent developments in the projects that I wanted to call out : An encoder for the Apple ProRes encoder from Kostya ; XWD (X window dump) image decoding and encoding from Paul B. Mahol ; a Sun rasterfile encoder from Aneesh Dogra.

  And then there’s the new playback system for CDXL files, also courtesy of Paul B. Mahol. I wasn’t familiar with this format until I wrote this post, which is surprising, given the format’s vintage. This was a CD-ROM FMV format favored for Amiga computers. Here it is in all its 160x120x10fps glory :

  
  
  

  That’s the amigaball.cdxl sample available in the repository. The sample is 3835910 bytes large and plays for about 24 seconds. This yields a data rate of about 159 kbytes/second. So, yeah, single-speed CD-ROM FMV.