Keyframe interval set to 2 seconds is the universal correct value for live streaming and the value most streamers leave at the OBS default of 0 (auto). The auto setting can produce keyframes too far apart, which makes the stream slower to recover after any data loss event and impairs how viewers can scrub through the VOD.

The mechanism: a keyframe is a complete picture frame, while the frames between keyframes encode only the changes since the last keyframe. A keyframe every 2 seconds means the viewer's player can recover the stream picture within 2 seconds of any disruption, which is the cap most platforms expect.

The implementation: open OBS settings, output, encoder settings, find the keyframe interval field, set it to 2. Save. Restart the stream test. Done.

The 2-second value is also a Twitch and YouTube ingest requirement at higher bitrate tiers. Streams violating the 2-second rule may be re-encoded by the platform on the fly, which costs quality. Set it once. Forget it.