c# ffmpeg stream piping example

ffmpeg-process-pining-MedallionShell.linq

<Query Kind="Program">
  <NuGetReference>MedallionShell</NuGetReference>
  <Namespace>System.Threading.Tasks</Namespace>
  <Namespace>Medallion.Shell</Namespace>
  <Namespace>Medallion.Shell.Streams</Namespace>
</Query>

DumpContainer dc;
async Task Main()
{	var input = @"D:\Temp\fieldtest.mxf".Dump("input file");
	var output = @"D:\Temp\out43.mp4".Dump("output file");
	var cmdPath =  @"D:\Temp\ffmpeg.exe"; 
	var args = "-i pipe:0 -c:v libx264 -b:v 2600k -c:a aac -b:a 128k -f mp4 -movflags frag_keyframe+empty_moov -y pipe:1";	
	$"{cmdPath} {args}".Dump("cmd line");
	dc = new DumpContainer().Dump("ffmpeg standard error out");
	
	using (var inputStream = File.OpenRead(input))
	using (var outputStream = File.OpenWrite(output))
	using (var cmd = Command.Run(cmdPath, options: o => o.StartInfo(i => i.Arguments = args)))
	{		
		var inputTask = cmd.StandardInput.PipeFromAsync(inputStream);
		var outputTask = cmd.StandardOutput.PipeToAsync(outputStream);
		var cs = new CancellationTokenSource();	
		var logTask = ReadError(cmd.StandardError, cs.Token);			
		await inputTask;
		await outputTask;
		cs.Cancel();
		await logTask;
	}
}

async Task ReadError(ProcessStreamReader reader, CancellationToken token) {
	while (!token.IsCancellationRequested)
		dc.Content += $"{await Task<string>.Run(reader.ReadLineAsync, token)}{Environment.NewLine}";
	
}