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• h265_videotoolbox for Apple Chips Not working with ffmpeg

  22 janvier 2024, par Martin Julien

  I have a 16-inch Macbook Pro.
System :
Model Name : MacBook Pro
Chip : Apple M1 Max
Total Number of Cores : 10 (8 performance and 2 efficiency)
Memory : 64 GB

  


  You can take advantage of apple chips to encode faster by replacing the usual line :
-c:v libx265 by -c:v h265_videotoolbox.

  


  Here's an example.
Since h265 doesn't work at the moment, here's a line that works just fine :

  


  for i in *.mp4; do ffmpeg -i "$i" -c:v h264_videotoolbox -b:v 2000k -c:a aac -b:a 192k -s 1920x1080 -threads 8 "${i%.*}_1.mp4"; done

  


  The version of ffmpeg installed on my mac is the latest : 6.1.1

  


  My problem :
I want to encode in h265. My command line is :
for i in *.mp4; do ffmpeg -i "$i" -c:v h265_videotoolbox -b:v 2000k -c:a aac -b:a 192k -s 1920x1080 -threads 8 "${i%.*}_1.mp4"; done

  


  Everything should work in theory. But I get this from the Shell :

  


  [vost#0:0 @ 0x150f06fd0] Unknown encoder 'h265_videotoolbox' [vost#0:0 @ 0x150f06fd0] Error selecting an encoder Error opening output file Denis_1.mp4. Error opening output files: Encoder not found

  


  My attempts :

  


  I spent a lot of time with ChatGPT to solve the problem, but nothing worked. So I'm asking the question here to see if anyone has had the same problem as me and if there's a solution to fix it.

  


  Thank you for your help,

  


  best regards,
Martin

  


• 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 ?

• Why does subprocess.run() have unexpected behavior in try else block ?

  27 novembre 2023, par Nikita Savenkov

  Trying to make a "to mp4" converter function using ffmpeg that is going to convert a file to mp4, delete the original file, and return True or False for specific conditions.
But I get some unexpected behavior of a subprocess.

  


  Initially I used this construction :

  


  def to_mp4_converter(file):

    input_file = file
    output_file = f"{re.sub(r'\..+$', "", file)}.mp4"

    try:
        subprocess.run(['ffmpeg', '-i', input_file, output_file])
    except subprocess.SubprocessError as e:
        print(f"Subprocess Error: {e}")
        return False
    else:
        try:
            os.remove(path=file)
        except OSError as e:
            print(f"Can't remove {file} file: {e}")
        finally:
            return True


  


  Original file is removed, but output file is half of the expected size and quality of video is low.

  


  But if I place subprocess.run() and os.remove() into separate try else blocks like that :

  


  def to_mp4_converter(file):

    input_file = file
    output_file = f"{re.sub(r'\..+$', "", file)}.mp4"

    try:
        subprocess.run(['ffmpeg', '-i', input_file, output_file])
    except subprocess.SubprocessError as e:
        print(f"Subprocess Error: {e}")
        return False
    else:
        pass

    try:
        os.remove(path=file)
    except OSError as e:
        print(f"Can't remove {file} file: {e}")
    finally:
        return True


  


  Everything works fine.

  


  Isn't subprocess.run() should be a blocking operation, so the else statement in 1st example is unreachable until conversion is done ?