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• C# UWP Desktop Bridge start ffmpeg with command

  4 décembre 2019, par iNCEPTiON_

  I have a UWP Application which starts a WPF app and communicates via AppServiceConnection which works well,
  what I want to do is to start FFmpeg / FFplay with the command to play a video.

  The code in the WPF app for starting FFmpeg / FFplay via AppServiceConnection

  private void Connection_RequestReceivedAsync(AppServiceConnection sender, AppServiceRequestReceivedEventArgs args)
  
          {
  
              var value = args.Request.Message["REQUEST"] as string;
  
              switch (value)
  
              {
  
                  case "StartFFmpeg":
  
                      Test();
  
                      break;
  
              }
  
          }
  
  
  
          private void Test()
  
          {
  
              var process = new Process();
  
              process.StartInfo.RedirectStandardOutput = true;
  
              process.StartInfo.RedirectStandardError = true;
  
              process.StartInfo.FileName = Path.GetDirectoryName(Process.GetCurrentProcess().MainModule.FileName) + @"\ffplay.exe";
  
              process.StartInfo.Arguments = @"-i C:\Users\test\video.mp4";
  
  
  
  
  
              process.StartInfo.UseShellExecute = false;
  
              process.StartInfo.CreateNoWindow = true;
  
              process.Start();
  
          }

  this fails with the following error in the UWP app :

  The target process exited without raising a CoreCLR started event. Ensure that the target process is configured to use .NET Core. This may be expected if the target process did not run on .NET Core.
  
  The program '[16824] FFmpeg.Bridge.exe' has exited with code -532462766 (0xe0434352).

  now my question is, is it possible to start FFmpeg / FFplay with the desktop bridge ? or can we only start .net core processes, the process is running with full privileges so why is that not possible ?

  The UWP App won’t be published on the store, it will only run on a local windows machine.

• Converting ffmpeg CLI command to ffmpeg-python to get bytes of a MPEG Transport Stream data stream ?

  28 août 2023, par kdeckerr

  I have the following code to get the bytes representing the data stream of a .ts video :

  


  def get_datastream_bytes(mpeg_ts_filepath):
    ffmpeg_command = [
        'ffmpeg', '-hide_banner', '-loglevel', 'quiet',
        '-i', mpeg_ts_filepath,
        '-map', '0:d',
        '-c', 'copy',
        '-copy_unknown',
        '-f', 'data',
        'pipe:1'
    ]

    try:
        output_bytes = subprocess.check_output(ffmpeg_command, stderr=subprocess.STDOUT)
        print("Output bytes length:", len(output_bytes))
        return output_bytes
    except subprocess.CalledProcessError as e:
        print("Error:", e.output)


  


  I can then wrap the returned value in io.BytesIO and parse the resulting bytes using another library (klvdata).

  


  This code was fashioned upon a ffmpeg CLI command I adapted from this SO Answer.

  


  ffmpeg -i "C:\inputfile.ts" -map 0:d -c copy -copy_unknown -f:d data pipe:1


  


  ---

  


  What I would really like to do is utilize the Python ffmpeg bindings in ffmpeg-python so that users do not have to install ffmpeg locally. Thus, I have attempted to get a bytes stream from an ffmpeg call like so :

  


  bytestream = (
    ffmpeg.input(input_file)
        .output("pipe:", format="data", codec="copy", copy_unknown=True)
        .run(capture_stdout=True)
)


  


  Though, this and many other, attempts at utilizing ffmpeg-python generally end with the same error :

  


  


  Output #0, data, to 'True' :
[out#0/data @ 00000...] Output file does not contain any stream
Error opening output file True.
Error opening output files : Invalid argument
Traceback (most recent call last) :
...
raise Error('ffmpeg', out, err)
ffmpeg._run.Error : ffmpeg error (see stderr output for detail)

  


  


  ---

  


  How do I convert the ffmpeg CLI command

  


  ffmpeg -i "C:\inputfile.ts" -map 0:d -c copy -copy_unknown -f:d data pipe:1


  


  To an ffmpeg-python call ?

  


• C# How do I set the volume of sound bytes[]

  23 juillet 2016, par McLucario

  Im trying to change the volume of sound bytes[] in C#. Im reading a sound file with FFMPEG and and wanna change the volume on the fly. I found some examples and but I didnt understand them.

  public void SendAudio(string pathOrUrl)
  
  {
  
      cancelVid = false;
  
      isPlaying = true;
  
  
  
      mProcess = Process.Start(new ProcessStartInfo
  
      { // FFmpeg requireqs us to spawn a process and hook into its stdout, so we will create a Process
  
          FileName = "ffmpeg",
  
          Arguments = "-i " + (char)34 + pathOrUrl + (char)34 + // Here we provide a list of arguments to feed into FFmpeg. -i means the location of the file/URL it will read from
  
          " -f s16le -ar 48000 -ac 2 pipe:1", // Next, we tell it to output 16-bit 48000Hz PCM, over 2 channels, to stdout.
  
          UseShellExecute = false,
  
          RedirectStandardOutput = true, // Capture the stdout of the process
  
          Verb = "runas"
  
      });
  
  
  
      while (!isRunning(mProcess)) { Task.Delay(1000); }
  
  
  
      int blockSize = 3840; // The size of bytes to read per frame; 1920 for mono
  
      byte[] buffer = new byte[blockSize];
  
      byte[] gainBuffer = new byte[blockSize];
  
      int byteCount; 
  
  
  
      while (true && !cancelVid) // Loop forever, so data will always be read
  
      {
  
          byteCount = mProcess.StandardOutput.BaseStream // Access the underlying MemoryStream from the stdout of FFmpeg
  
          .Read(buffer, 0, blockSize); // Read stdout into the buffer
  
  
  
          if (byteCount == 0) // FFmpeg did not output anything
  
              break; // Break out of the while(true) loop, since there was nothing to read.
  
  
  
          if (cancelVid)
  
              break;
  
  
  
          disAudioClient.Send(buffer, 0, byteCount); // Send our data to Discord
  
      }
  
      disAudioClient.Wait(); // Wait for the Voice Client to finish sending data, as ffMPEG may have already finished buffering out a song, and it is unsafe to return now.
  
      isPlaying = false;
  
      Console.Clear();
  
      Console.WriteLine("Done Playing!");