How to properly pipe adb screenrecord (h264 stream) to ffplay in a WinForms app?

Question

How to pipe ADB's exec out to ffplay?

I have been struggling to get this "Live view" C# WinForms app working properly this last week. The goal is to have the android screen in the native app window where I then have other controls implemented as an overlay.

I am able to live stream by piping adb's screen record H264 into FFplay via CMD. A CMD process that launches a .BAT does function, but I can't manipulate FFplay as control seems to be lost with how it's launched (Correct if wrong). I just need a programmatic version of this where I can then control the FFplay window to merge it as a child into my form.

adb exec-out screenrecord --output-format=h264 - | ffplay -window_title "Live View" -framerate 60 -framedrop -probesize 32 -sync video  -

I also attempted creating a ADB and FFplay process, manually trying to write the standard in from ADB's standard out. The standard out was received but I couldn't figure out writing to ffplay correctly. May have had a same thread deadlock issue.

        //Configure ffplay process and start
        //ffplayProcess.SynchronizingObject();
        ffplayProcess.OutputDataReceived += (o, ev) => Debug.WriteLine(ev.Data ?? "NULL", "ffplay");
        ffplayProcess.ErrorDataReceived += (o, ev) => Debug.WriteLine(ev.Data ?? "NULL", "ffplay");
        ffplayProcess.Exited += (o, ev) => Debug.WriteLine("Exited", "ffplay");
        try
        {
            ffplayProcess.Start();
        }
        catch (Exception err)
        {
            MessageBox.Show($"Failed to start livestream. {err.Message}", "Live Stream Error", MessageBoxButtons.OK, MessageBoxIcon.Error);
            return;
        }

        //Wait/check the process started, then...
        System.Threading.Thread.Sleep(200);

        //Run only if ffplay has not exited
        if (ffplayProcess.HasExited == false)
        {
            // make 'this' the parent of ffmpeg (presuming you are in scope of a Form or Control)
            SetParent(ffplayProcess.MainWindowHandle, this.Handle);
            MoveWindow(ffplayProcess.MainWindowHandle, 0, 0, 240, 320, true);
        }

        adbProcess.OutputDataReceived += (o, ev) => {
            Debug.WriteLine(ev.Data ?? "NULL", "adb");

            if (ev.Data != "NULL" || ev.Data != null)
            {
                //Convert data to byte array
                //byte[] dataBytes = Encoding.ASCII.GetBytes(ev.Data);
                byte[] dataBytes = Encoding.UTF8.GetBytes(ev.Data);
                ffplayProcess.StandardInput.BaseStream.WriteAsync(dataBytes, 0, dataBytes.Length);
                ffplayProcess.StandardInput.BaseStream.FlushAsync();
            }
        };
        adbProcess.ErrorDataReceived += (o, ev) => Debug.WriteLine(ev.Data ?? "NULL", "adb");
        adbProcess.Exited += (o, ev) => Debug.WriteLine("Exited", "adb");

        adbProcess.Start();

        adbProcess.BeginOutputReadLine();
        adbProcess.BeginErrorReadLine();

My current attempt is using MedallionShell to pipe into the FFplay process. ADB and FFPlay launch, but I never get FFplay's video out window.

private void FormLiveView_Load(object sender, EventArgs e)
{
        var command = Medallion.Shell.Command.Run(tmpPath + "/adb.exe", new[] { "exec-out screenrecord --output-format=h264 -" }, options => { options.DisposeOnExit(false); });
            
        command.PipeTo(Medallion.Shell.Command.Run(tmpPath + "/ffplay.exe", new[] { "-framerate 60 -framedrop -probesize 32 -sync video -" }, options => { options.DisposeOnExit(false); }));
}