Stream to Custom SRT Server in OBS Studio

This guide provides a straightforward, step-by-step walkthrough on how to configure OBS Studio to stream live video to a custom Secure Reliable Transport (SRT) server. SRT is an open-source video transport protocol designed for low-latency, secure, and reliable streaming over unstable networks. By the end of this article, you will know how to format your SRT connection string, input the correct settings into OBS Studio, and optimize your encoder settings for a successful SRT broadcast.

Step 1: Collect Your SRT Server Details

Before configuring OBS Studio, you need the connection details of your target SRT server. You will need: * IP Address or Domain Name of the server. * Port Number assigned for your SRT stream (e.g., 9000). * Stream ID (optional, but often required by multi-stream servers to identify your specific feed).

Step 2: Configure Stream Settings in OBS Studio

  1. Open OBS Studio.
  2. Click on Settings in the bottom-right corner (or go to File > Settings).
  3. Select the Stream tab from the left-hand menu.
  4. Click the Service dropdown menu and select Custom….
  5. In the Server field, enter your SRT connection string using the following format: srt://[IP_Address]:[Port]?mode=caller Example: srt://192.168.1.100:9000?mode=caller
  6. If your server requires a Stream ID, append it to the end of your Server URL using the streamid parameter: srt://[IP_Address]:[Port]?mode=caller&streamid=your_stream_id Example: srt://192.168.1.100:9000?mode=caller&streamid=live/stream1
  7. Leave the Stream Key field blank, as all routing parameters are handled within the SRT Server URL.

Step 3: Optimize Video and Encoder Settings

Because SRT is designed for low-latency transmission, optimizing your encoder settings ensures the best performance: 1. Go to the Output tab in the OBS Settings menu. 2. Set the Output Mode to Advanced. 3. Choose your encoder (e.g., NVIDIA NVENC H.264 or x264). 4. Set the Rate Control to CBR (Constant Bitrate). 5. Set your Bitrate according to your network upload capacity (typically between 3000 Kbps and 6000 Kbps for 1080p). 6. Set the Keyframe Interval to 2 seconds. 7. If you are using NVIDIA NVENC, set the Preset to Low-Latency or Max Quality, and set the Profile to high.

Step 4: Adjust Latency (Optional)

If you experience buffering or frame drops over a highly unstable connection, you can increase the latency buffer in the SRT URL. By default, OBS uses a built-in latency, but you can manually define it in microseconds (e.g., 120000 microseconds equals 120 milliseconds): srt://[IP_Address]:[Port]?mode=caller&latency=120000

Step 5: Start the Stream

Once your settings are saved, click Apply and then OK. Click the Start Streaming button on the main OBS Studio dashboard. Look at the status bar at the bottom right; a green square and stable bitrate indicate a successful connection to your custom SRT server.