it is possible to stream video with SignalR?

Question

Well I\'m trying to perform a proof about video streaming, I\'m working with asp.net c#. I\'m kind of lost, you have any idea or suggestion?

Answer 1

I do not know if SignalR is intentioned for working with video stream or not but SignalR is a Hub container between client-to-client client-to-server and server-to-client. If I want a Video-chat why I can not use it as my hub? Anyway SignalR can handle array of bytes too and not only Strings then let try by sending each frame as a byte[] (Stream). At least when I using only .Net I can hub byte[]. When I put in Python then I need to serialize to string with base64 and it is working from my PI too. Put an eye on my lab-solution I push into my GIT. https://github.com/Guille1878/VideoChat

SignalR Hub (Default, not serverless)

namespace ChatHub
{
    public interface IVideoChatClient
    {
        Task DownloadStream(byte[] stream);
    }

    public class VideoChatHub : Hub 
    {
        public async Task UploadStream(byte[] stream)
        {
            await Clients.All.DownloadStream(stream);
        }
    }
}

Video-Sender: (UWP)

while (isStreamingOut)
{
      var previewProperties = mediaCapture.VideoDeviceController.GetMediaStreamProperties(MediaStreamType.VideoPreview) as VideoEncodingProperties;

      VideoFrame videoFrame = new VideoFrame(BitmapPixelFormat.Bgra8, (int)previewProperties.Width, (int)previewProperties.Height);
    
      Var frame = await mediaCapture.GetPreviewFrameAsync(videoFrame)

      if (frame == null)
      {
            await Task.Delay(delayMilliSeconds);
            continue;
      }

      var memoryRandomAccessStream = new InMemoryRandomAccessStream();
      var encoder = await BitmapEncoder.CreateAsync(BitmapEncoder.JpegEncoderId, memoryRandomAccessStream);
      encoder.SetSoftwareBitmap(frame.SoftwareBitmap);  
      encoder.IsThumbnailGenerated = false;
      await encoder.FlushAsync();

      try
      {
             var array = new byte[memoryRandomAccessStream.Size];
             await memoryRandomAccessStream.ReadAsync(array.AsBuffer(), (uint)memoryRandomAccessStream.Size, InputStreamOptions.None);

             if (array.Any())
                  await connection.InvokeAsync("UploadStream", array);                   
       }
       catch (Exception ex)
       {
              System.Diagnostics.Debug.WriteLine(ex.Message);
       }

       await Task.Delay(5);
}

Video-receiver: (UWP)

private async void StreamVideo_Click(object sender, RoutedEventArgs e)
{
      isStreamingIn = StreamVideo.IsChecked ?? false;
      if (isStreamingIn)
      {
            hubConnection.On("DownloadStream", (stream) =>
            {
                  _ = this.Dispatcher.RunAsync(CoreDispatcherPriority.Normal, () =>
                  {
                       if (isStreamingIn)
                           StreamedArraysQueue.Enqueue(stream);
                  });
             });

             if (hubConnection.State == HubConnectionState.Disconnected)
                  await hubConnection.StartAsync();

              _ = BuildImageFrames();
           }
       }     
}

private async Task BuildImageFrames()
{
      while (isStreamingIn)
      {
            await Task.Delay(5);

            StreamedArraysQueue.TryDequeue(out byte[] buffer);

            if (!(buffer?.Any() ?? false))
                  continue;

            try
            {
                    var randomAccessStream = new InMemoryRandomAccessStream();
                    await randomAccessStream.WriteAsync(buffer.AsBuffer());
                    randomAccessStream.Seek(0); 
                    await randomAccessStream.FlushAsync();

                    var decoder = await BitmapDecoder.CreateAsync(randomAccessStream);

                    var softwareBitmap = await decoder.GetSoftwareBitmapAsync();

                    var imageSource = await ConvertToSoftwareBitmapSource(softwareBitmap);

                    ImageVideo.Source = imageSource;
             }
             catch (Exception ex)
             {
                    System.Diagnostics.Debug.WriteLine(ex.Message);
             }
       }
}

I am using "SignalR Core"