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RTMP streaming

Products: Video Capture SDK .Net, Video Edit SDK .Net, Media Blocks SDK .Net

RTMP (Real-Time Messaging Protocol) output in VisioForge provides a robust solution for streaming video and audio content over the internet. This guide explains how to configure and use RTMP output effectively in your applications.

Cross-platform RTMP output (X-engines: VideoCaptureCoreX, VideoEditCoreX, Media Blocks)

The RTMPOutput class serves as a comprehensive configuration hub for RTMP streaming, supporting various video and audio encoders across different platforms. It implements multiple interfaces including IVideoEditXBaseOutput and IVideoCaptureXBaseOutput, making it versatile for both video editing and capture scenarios.

Basic Setup

To begin using RTMP output, you'll need to create an instance with your streaming URL:

var rtmpOutput = new RTMPOutput("rtmp://your-streaming-server/stream-key");

If you don't have the URL ready during initialization, you can set it later:

var rtmpOutput = new RTMPOutput();
rtmpOutput.Sink.Location = "rtmp://your-streaming-server/stream-key";

Set the output to the Video Capture SDK engine.

core.Outputs_Add(rtmpOutput, true); // core is an instance of VideoCaptureCoreX

Set the output to the Video Edit SDK engine.

core.Output_Format = rtmpOutput; // videoEdit is an instance of VideoEditCoreX

Media Blocks SDK sample:

var rtmpSink = new RTMPSinkBlock(new RTMPSinkSettings() { Location = "rtmp://streaming-server/stream" });

pipeline.Connect(h264Encoder.Output, rtmpSink.CreateNewInput(MediaBlockPadMediaType.Video));
pipeline.Connect(aacEncoder.Output, rtmpSink.CreateNewInput(MediaBlockPadMediaType.Audio));

Video Encoder Configuration

The RTMPOutput class supports multiple video encoders, automatically selecting the most appropriate default based on your platform:

Supported Video Encoders

  • OpenH264 (Default for most platforms)
  • NVENC H264 (NVIDIA GPU acceleration)
  • QSV H264 (Intel Quick Sync)
  • AMF H264 (AMD acceleration)
  • HEVC/H265 variants (MF HEVC, NVENC HEVC, QSV HEVC, AMF H265)

Example of configuring a specific video encoder:

// Using NVIDIA encoder if available
if (NVENCH264EncoderSettings.IsAvailable())
{
    rtmpOutput.Video = new NVENCH264EncoderSettings();
}

Audio Encoder Configuration

The system supports various AAC encoders, with platform-specific defaults:

Supported Audio Encoders

  • VO-AAC (Default for non-Windows platforms)
  • AVENC AAC
  • MF AAC (Default for Windows)

Example of custom audio encoder configuration:

// Using MF AAC encoder on Windows
rtmpOutput.Audio = new MFAACEncoderSettings();

Platform-Specific Considerations

Windows

  • Default video encoder: OpenH264
  • Default audio encoder: MF AAC
  • Additional support for Microsoft Media Foundation HEVC encoding

macOS

  • Uses AppleMediaH264EncoderSettings for video encoding
  • Default audio encoder: VO-AAC

Cross-Platform Compatibility

The class automatically handles platform-specific differences through conditional compilation:

#if __MACOS__
    Video = new AppleMediaH264EncoderSettings();
#else
    Video = new OpenH264EncoderSettings();
#endif

Best Practices

  1. Encoder Selection: Always check encoder availability before using hardware-accelerated options:

    if (NVENCH264EncoderSettings.IsAvailable())
    {
        // Use NVIDIA encoding
    }

  2. Error Handling: Implement proper error handling when setting up streaming:

    try
    {
        var rtmpOutput = new RTMPOutput(streamUrl);
        // Configure encoders and start streaming
    }
    catch (Exception ex)
    {
        // Handle initialization errors
    }

  3. Resource Management: Properly dispose of resources when streaming is complete.

Advanced Usage

Dynamic Encoder Selection

You can programmatically enumerate available encoders:

var rtmpOutput = new RTMPOutput();
var availableVideoEncoders = rtmpOutput.GetVideoEncoders();
var availableAudioEncoders = rtmpOutput.GetAudioEncoders();

Custom Sink Configuration

The RTMPSinkSettings class allows for detailed streaming configuration:

rtmpOutput.Sink = new RTMPSinkSettings
{
    Location = "rtmp://streaming-server/stream",
    // Additional sink configuration as needed
};

Troubleshooting

Common issues to watch for:

  • Ensure proper URL formatting for your streaming service
  • Check encoder availability before attempting to use hardware acceleration
  • Monitor system resources when using software encoding
  • Verify network connectivity and bandwidth availability

Performance Considerations

To achieve optimal streaming performance:

  1. Choose hardware-accelerated encoders when available
  2. Monitor CPU and GPU usage
  3. Ensure proper network bandwidth
  4. Consider using lower encoding profiles for constrained environments

Windows-only RTSP output (VideoCaptureCore and VideoEditCore engines)

Video and audio encoder configuration

Set the Network_Streaming_Enabled property to true to enable network streaming.

VideoCapture1.Network_Streaming_Enabled = true;

Set network streaming format to RTMP_FFMPEG_EXE and create FFMPEGEXEOutput object.

VideoCapture1.Network_Streaming_Format = NetworkStreamingFormat.RTMP_FFMPEG_EXE;

var ffmpegOutput = new FFMPEGEXEOutput();

Set the output format and video and audio codecs.

ffmpegOutput.FillDefaults(DefaultsProfile.MP4_H264_AAC, true);

Set the output muxer.

ffmpegOutput.OutputMuxer = OutputMuxer.FLV;

Configure output.

VideoCapture1.Network_Streaming_Output = ffmpegOutput;

Enable audio streaming (required for YouTube and Facebook Live).

VideoCapture1.Network_Streaming_Audio_Enabled = true;

YouTube streaming

Set the URL to rtmp://a.rtmp.youtube.com/live2/ + YouTube stream key.

VideoCapture1.Network_Streaming_URL = "rtmp://a.rtmp.youtube.com/live2/" + "YOUR KEY HERE";

Facebook Live streaming

Set the URL to rtmps://live-api-s.facebook.com:443/rtmp/ + Facebook stream key.

VideoCapture1.Network_Streaming_URL = "rtmps://live-api-s.facebook.com:443/rtmp/" + "YOUR KEY HERE";

Other RTMP servers

Set the URL to the RTMP server URL.

VideoCapture1.Network_Streaming_URL = "rtmp server url";

See also