Aircast

Stream with SRT

Last updated July 3, 2026

SRT (Secure Reliable Transport) is a modern streaming protocol that handles unstable connections better than RTMP. Aircast now accepts SRT alongside RTMP, so if your connection tends to drop or stutter — say you’re on Wi-Fi or mobile data — SRT is worth a try. If RTMP is already working well for you, there’s no need to switch.

Setup is almost identical to RTMP: you point your encoder at Aircast and we’ll handle the rest. There’s just one thing SRT is picky about — codecs — so don’t skip the warning below.

Step 1: Set up your input in Aircast

On your stream profile, choose Stream with RTMP/SRT as your input. If another input is currently active, click Switch Channel first.

The input card has an RTMP | SRT protocol selector. Click SRT, and you’ll see the server URL, your stream key, and the codec warning.

Step 2: Set up OBS

In OBS, go to File > Settings > Stream and enter:

  • Service: Custom
  • Server: srt://ingest.aircast.app:10080
  • Stream Key: your Aircast stream key (shown on the SRT tab)

⚠️ The SRT URL has no path, and your stream key never goes in the URL. If you’re used to the RTMP address (rtmp://ingest.aircast.app/live/), don’t copy that pattern across — the SRT server address ends at the port number, with nothing after it. Your key always goes in the separate Stream Key field.

Step 3: Check your codecs

⚠️ SRT requires H.264 video and AAC audio. Streams using HEVC or AV1 will fail to start.

Here’s why this catches people out: over RTMP, OBS only lets you stream H.264, so you can’t get it wrong. Over SRT, OBS also allows HEVC and AV1, so it’s easy to pick an unsupported encoder without realising.

In OBS, go to Settings > Output > Streaming and make sure your video encoder is an H.264 one — x264, or a hardware H.264 encoder like NVENC H.264.

Aircast doesn’t limit your bitrate or frame rate on the way in, but the platforms you’re streaming out to may have their own limits — so it’s worth checking what your destinations accept.

Step 4: Go live

Start streaming in OBS, and start your input and outputs in Aircast the same way you would with RTMP.

Auto-start works too: enable auto-start on the input and on each output you want started when you go live, and Aircast will take care of it.

Troubleshooting: my stream won’t start

Work through these in order — the first one is by far the most common:

  1. Check your codecs. In OBS, go to Settings > Output > Streaming and confirm your video encoder is H.264 (x264 or a hardware H.264 encoder like NVENC H.264) and your audio is AAC. HEVC and AV1 streams will not start.
  2. Check the server URL. It should be exactly srt://ingest.aircast.app:10080 — no path, nothing after the port number.
  3. Check where your stream key is. It belongs in the Stream Key field in OBS, never appended to the URL.

FAQ

Is my stream key different for SRT? No — it’s the same key you use for RTMP, shown on your stream profile page.

Can I still use RTMP? Yes. The protocol selector defaults to RTMP, and you can switch between the two whenever you like.

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