Configure OBS Studio for Custom SRT Streaming

This article provides a straightforward, step-by-step guide on how to configure OBS Studio to stream video to a custom destination server using the Secure Reliable Transport (SRT) protocol. You will learn how to set up your custom stream URL, configure essential latency parameters, optimize your encoder settings for low-latency delivery, and successfully initiate your live broadcast.

Step 1: Gather Your SRT Server Details

Before configuring OBS Studio, you need the connection details from your custom SRT ingest server. A standard SRT connection string uses the following format:

srt://[server-ip-or-domain]:[port]

If your server requires a specific Stream ID to identify your feed, the stream ID is usually appended as a parameter:

srt://[server-ip-or-domain]:[port]?streamid=[your-stream-id]

Step 2: Configure Stream Settings in OBS

Once you have your connection string, you need to input it into OBS Studio.

1. Open OBS Studio.
2. Click on Settings in the bottom-right control panel, 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, paste your SRT connection string.
6. Leave the Stream Key field blank, as SRT authentication and routing are handled entirely within the SRT URL in the Server field.

Optional: Fine-Tuning SRT Parameters

You can append parameters to the end of your SRT URL to optimize performance. Separate parameters using the & symbol.

• Latency: You can manually set the latency in microseconds (e.g., 120 milliseconds is 120000).
  • Example: srt://192.168.1.100:9000?mode=caller&latency=120000
• Passphrase: If your server requires encryption, append the passphrase and key length.
  • Example: srt://192.168.1.100:9000?passphrase=YourPassword&pbkeylen=16

Step 3: Optimize Encoder Settings

To get the best performance out of the SRT protocol, adjust your output settings to prioritize low latency and stability.

1. In the Settings window, click on the Output tab.
2. Change the Output Mode at the top from Simple to Advanced.
3. Under the Streaming tab, configure the following settings:
   • Encoder: Select your hardware encoder (such as NVIDIA NVENC H.264 or AMD HW H.264) for the best performance, or x264 if hardware encoding is unavailable.
   • Rate Control: Set this to CBR (Constant Bitrate).
   • Bitrate: Set a bitrate appropriate for your upload bandwidth (e.g., 4000 Kbps to 6000 Kbps for 1080p60).
   • Keyframe Interval: Set this to 2s.
   • Preset: Choose Low-Latency or Quality (avoid Max Quality as it can introduce frame buffering).
   • Profile: Set to high or main.

Click Apply and then OK to save your settings.

Step 4: Start Streaming

With the stream destination and encoder configured, you are ready to go live. Click the Start Streaming button in the main OBS Studio window. OBS will establish a secure, low-latency connection to your custom SRT server and begin transmitting your video feed.