OBS lets you record in several container formats, but the choice usually comes down to MKV versus MP4. Pick wrong and a single crash can corrupt an entire recording — or your editor may refuse to open the file. The short answer: record in MKV, then remux to MP4. This guide explains why that workflow exists and when a straight MP4 recording is fine.
The core tradeoff: safety vs compatibility
MP4 is the universal format. Every editor, phone, and social platform accepts it without fuss. Its weakness is fragility: MP4 writes critical index data at the end of the file, so if OBS crashes, your PC loses power, or the recording stops abnormally, the whole file can become unplayable. MKV writes data progressively, so an interrupted MKV is almost always still usable up to the moment it stopped.
| Factor | MKV | MP4 |
|---|---|---|
| Crash safety | Excellent — file survives interruptions | Poor — crash can corrupt entire recording |
| Editor compatibility | Limited (some editors reject it) | Universal |
| Multiple audio tracks | Fully supported | Supported but less consistent |
| Remux to other format | Fast, lossless | N/A |
| Direct upload to social | Usually needs conversion | Ready to go |
The recommended workflow
Record in MKV for safety, then use OBS’s built-in “Remux Recordings” tool to convert to MP4 when the session ends. Remuxing simply repackages the existing video and audio into a new container — it is lossless and takes seconds because nothing is re-encoded. You get MKV’s crash protection during recording and MP4’s compatibility for editing and uploading.
Automate it
OBS has a setting to automatically remux MKV recordings to MP4 as soon as they finish. Enable it and the safe-record, compatible-output loop happens without you thinking about it. This is the closest thing to a free win in your recording pipeline.
When plain MP4 is fine
If you are recording short, low-stakes clips on a stable machine and want to drag them straight into a phone editor, recording directly to MP4 saves the remux step. The risk is only meaningful for long sessions where a crash would cost you an irreplaceable recording — a two-hour tournament VOD is exactly where MKV earns its keep.
Multi-track audio favors MKV
If you record separate tracks for voice, game, music, and chat so you can balance them in editing, MKV handles multiple audio tracks more gracefully. That alone pushes serious editors toward the MKV-then-remux approach.
Managing recording files and storage
Long recordings pile up fast. A single hour of 1080p60 gameplay at a high recording bitrate can easily run 5–10 GB, so a weekend of streams can swallow 100 GB before you notice. Point OBS at a dedicated drive with plenty of space rather than your system SSD, and clear out remuxed originals once the MP4 exists, since keeping both the MKV and the MP4 doubles your storage for no benefit.
Build a simple naming and folder habit so you can actually find footage later. Enabling OBS’s automatic file-naming with the date and time, then sorting recordings into per-month folders, turns a chaotic dump into a searchable archive. If you record separate audio tracks for editing, keep those MKV originals until the edit is done — they hold the isolated stems — then remux the final version to MP4 and archive or delete the rest. A little discipline here prevents the classic scramble of hunting through fifty identically named files for one highlight.
Frequently asked questions
Does remuxing reduce quality?
No. Remuxing copies the existing encoded streams into a new container without re-encoding, so the output is bit-for-bit identical in quality and finishes almost instantly.
My editor won’t open my OBS recording — why?
It is probably an MKV file, which some editors reject. Remux it to MP4 first, or set OBS to record MP4 directly if crash safety is not a concern for that session.
Bottom line
Record MKV, output MP4. Turn on automatic remuxing and you get the best of both: recordings that survive crashes and files that open anywhere. Reserve direct MP4 only for short, disposable clips where speed beats safety.
