Your contribution encoder sends the live feed to RMS. The settings you configure affect stream stability, latency, and quality. This page covers baseline encoder configuration that applies to all RMS live events. For low-latency-specific tuning, see Live streaming low latency best practices.
Before you begin:
- You need a running live event and its ingest URL before you can configure your encoder. See Live streaming quickstart for the full setup steps.
- If you haven't chosen an event type yet, see Live streaming: event types and compatibility.
Encoder settings
The settings below use OBS Studio as a reference, but the principles apply to any encoder. In OBS, open Settings > Output and set the Output Mode to Advanced to find these parameters.
The following settings apply to all RMS live events:
| Parameter | Recommended value |
|---|---|
| Audio codec | AAC |
| GOP | 2 seconds |
| Keyframe interval | 2 seconds |
| Rate control |
|
| Video encoder |
Use a GPU encoder when available (offloads CPU work):
|
| Preset | P4: Medium (Medium Quality) |
| Multipass mode | Single pass |
Resolution and frame rate differ between passthrough and ABR:
| Parameter | Passthrough | ABR |
|---|---|---|
| Resolution | No limit | 1080p or below (matches the ladder caps) |
| Frame rate | No limit (30 fps recommended for stable playback) | 30 fps (ladder cap) |
Bitrate and bandwidth
- Set the encoding bitrate to no more than half your upload speed for stable streaming. For example, with a 20,000 Kbps upload, cap your encoding bitrate at 10,000 Kbps.
- For ABR events, encode at about 25% above your target top-rendition bitrate. The transcoder uses this headroom to maintain quality across the output ladder. For example, to deliver a 4,000 Kbps top rendition, send 5,000 Kbps to RMS. Passthrough does not need this headroom - RMS delivers your stream at exactly the bitrate you send.
Stability and testing
- Do not change the encoder configuration after streaming starts. Mid-stream changes cause instability.
- Use a hardwired connection when possible.
- Close unnecessary programs when using software encoders.
- Test new encoder versions for compatibility before relying on them in production.
- For RTMPS ingest, make sure your encoder supports TLS 1.2.
- Monitor CPU, memory, and disk I/O on the encoding machine. Fragment upload is resource-intensive.
- Schedule rehearsal time before a high-scale event - we recommend at least an hour for setup and a test stream.
Next steps
Live streaming quickstart - create your first live event and get a working stream from start to finish.
- Live streaming low latency best practices - reduce stream latency for real-time interactions.