Twitch is currently issuing a warning in preparation for their switch to HLS
if you don't have a keyframe interval set. By default, OBS relies on the x264 auto keyframe interval, which puts keyframes at scenecuts for the best quality. Unfortunately this is incompatible with HLS which needs fixed size GOPs, for which Twitch wants a 2 second keyframe interval.v0.55b or higher:
To change your keyframe interval, goto Settings, Advanced, and enter 2 seconds into the keyframe interval box (example
To change your keyframe interval, goto Settings, Advanced and in the Custom x264 settings box, enter:keyint=X
Where X is your FPS x 2 . Eg, if you stream at 30 FPS, you would use keyint=60, 48 FPS would be keyint=96, and 60 FPS would be keyint=120. (Example
Future versions of OBS will not require using the custom x264 settings, as this option will be available in the UI.
Also note that the Twitch.tv "Stream Configuration Quality" check is very new and will sometimes report incorrect keyframe intervals despite setting it correctly; it will also sometimes show unknown audio and video codecs. These warnings can safely be ignored once you have set the keyframe interval as above. Note that the twitch.tv guide linked in the message is incorrect when it describes how to set keyframe interval in OBS, this guide shows the correct way.