An editor may reject an OBS MKV file even though its encoded video is supported. Remuxing can put the existing encoded media into another container. It does not choose a new video codec, resize the picture or repair a poor recording.

Identify the compatibility question

Keep the original recording and note its duration, video codec and required audio tracks. Compare those details with the receiving editor's supported formats. The relevant question is whether the editor rejects the container or the encoded media inside it.

For an appropriate MKV-to-MP4 case, open File, Remux Recordings in OBS. Select the source with the browse control, inspect the proposed destination and start Remux. Wait for completion before opening the result. Choose a destination that keeps the original identifiable and has space for the additional file.

Do not use this as a file-size reduction step. A container change is different from re-encoding, and it does not turn an unsupported codec into a supported one. If the editor requires different encoding, plan a separate conversion from the retained source.

Check the editor's actual import

Import the remuxed file into a small test project. Check the beginning, a recognisable moment in the middle and the ending. Confirm that duration, sound and picture alignment remain useful and that the editor exposes the audio tracks required for the job.

If the original has separated narration and demonstration tracks, write down which imported track corresponds to each. A file that opens with a picture but omits the needed track is not an accepted editing handover.

OBS also offers automatic remuxing after recording stops. Enable it only after a representative manual test meets your workflow's requirements.

For future captures, inspect the exact recording-format choice. Modern OBS includes Hybrid MP4 and Hybrid MOV; these differ from traditional MP4/MOV recording. Avoid changing a working setup based on an old claim that every MP4 recording has identical recovery behaviour.

Sources: OBS documentation, OBS documentation, OBS developer explanation, OBS documentation.