Keyframe interval set to 2 seconds is the third non-negotiable in your encoder configuration. The setting determines how often the encoder sends a complete picture frame versus the smaller delta frames that encode only the changes between keyframes.

The 2-second interval is the value every major platform's ingest server expects. Twitch and YouTube both list 2 seconds as the recommended keyframe interval for live ingest, with values outside that range potentially triggering platform-side adjustments.

The implementation: in OBS Advanced output mode, encoder settings, find the keyframe interval field, set to 2. Save. The setting persists across streams.

The visible effect of correct keyframe interval: cleaner stream recovery after any data interruption, faster scrubbing for VOD viewers, and better behavior with platform features that depend on keyframe alignment (Twitch's clip system, YouTube's Live Replay system).

Streamers who leave the keyframe interval at 0 (auto) sometimes see auto-selected values that work but are not optimal. Setting it explicitly to 2 removes the variable.