OBS's entire published rule about recording formats and multiple audio tracks is two sentences long. From its guide on advanced recording and multi-track audio:
"Not all recording formats (container) allow for multi track audio. We suggest using mkv (you can remux later to mp4)."
That is the whole official position on which container to pick. There is no table in OBS's documentation listing how many audio tracks each container holds — which matters, because that is exactly the number most people are searching for. This page gives you what OBS does state, verbatim, and is explicit about where the documentation stops.
The limits, at a glance
| Question | What OBS's documentation states |
|---|---|
| Which container for multi-track? | "We suggest using mkv (you can remux later to mp4)" |
| Which container definitely cannot? | FLV — "only supports a single audio track" |
| Track count ceiling | "record multiple audio track (up to 6)" |
| Where tracks get assigned | Advanced Audio Properties (Audio Mixer gear icon) |
| Where tracks get enabled | Settings → Output |
| Output mode | OBS's guide tells you to switch to Advanced Output Mode to get these options |
| Per-container track counts (MP4, MOV, TS…) | Not stated anywhere in OBS's knowledge base — see official docs |
That last row is the honest answer to "how many tracks does MP4 hold in OBS." You will find confident numbers for it online. They are not in OBS's documentation, so this page will not repeat them.
What OBS does say about containers
Two statements, and only two, connect containers to track counts.
The first is the suggestion quoted above: MKV, with remuxing to MP4 afterwards if you need MP4. The second is in the Audio/Video Formats Guide, in the entry for FLV:
"FLV is the container used in RTMP. It has very limited codec support (H.264/AAC) and only supports a single audio track. It is resilient like MKV but rarely supported by editing software."
So FLV is the one container OBS explicitly rules out. For every other container, OBS says only that "not all" formats allow multi-track — without saying which ones, or how many tracks each takes.
The practical reading: follow the suggestion. MKV is what OBS recommends, and it is the container the same guide describes as compatible with everything else OBS can produce — "MKV supports every single codec combination possible in OBS Studio and is the default container."
The official table that does exist: containers × audio codecs
OBS does publish a codec compatibility table. It is about codecs rather than track counts, but it constrains your choices in a way that is easy to trip over — reproduced here exactly as OBS gives it:
| Container | AAC | ALAC | FLAC | Opus | PCM |
|---|---|---|---|---|---|
| FLV | ✅ | ❌ | ❌ | ❌ | ❌ |
| MP4 | ✅ | ✅ | ✅ | ✅ | ✅ |
| MOV | ✅ | ✅ | ❌ | ❌ | ✅ |
| MKV | ✅ | ✅ | ✅ | ✅ | ✅ |
| M3U8 (HLS) | ✅ | ❌ | ❌ | ✅ | ❌ |
| TS | ✅ | ❌ | ❌ | ✅ | ❌ |
Read it alongside the format advice and a pattern appears: the container OBS steers you toward accepts everything. MKV takes all five audio codecs. MOV drops FLAC and Opus. FLV takes AAC only, consistent with its single-track limitation. That matters if you follow OBS's quality recommendation of "high-bitrate AAC or lossless audio (e.g. ALAC)" — ALAC is available in MP4, MOV and MKV, but not in FLV, HLS or TS.
Six tracks, and the two places you have to touch
The ceiling has an official source. From the same advanced recording guide:
"This will allow you to record multiple audio track (up to 6), as well as choose a different encoder from the stream encoder."
The preceding sentence tells you how to reach those options: "If you want to record multiple audio tracks and maybe stream at the same time switch to the Advanced Output Mode at the top which will give you full control of all the settings." That is written as instruction, not as an exclusivity claim — OBS does not say Simple mode is incapable, it says Advanced mode is where the full set of controls lives.
The part that actually breaks people's recordings is that assigning tracks and enabling tracks are two different screens. OBS's step-by-step is explicit:
- "In the Audio Mixer dock, click the gear icon at the bottom left to open up the Advanced Audio Properties window" — this is also reachable from Edit in the menu bar.
- "Assign each of your audio sources to its own recording track."
- "Go to the Settings → Output window and enable the tracks that you would like to record."
Do step 2 and skip step 3 and you get a file with one track, having carefully split your sources onto six.
One more official detail: in OBS's own worked example, track 1 keeps everything — "I'm going to leave all my source enabled on 'Track 1', because that is the default for the stream, and I want it to contain all sources" — while tracks 2, 3 and 4 hold comms, desktop/game audio and mic separately. A full mix on track 1 is documented practice, not a community trick, and it is what stops a multi-track file from playing silently in an ordinary player. If you already have a silent recording, see why OBS recordings end up with no audio.
What to do about the "remux later to mp4" half
OBS's suggestion has two parts, and the second one exists because of a separate documented problem with recording straight to MP4:
"MP4/MOV require 'finalisation' of a file to be playable, if the writing is interrupted for any reason the file may not be recoverable. It is therefore not recommended to record to MP4/MOV directly."
MKV gets the opposite treatment: it "will not corrupt the whole file if there is no graceful stoppage of recording." So the MKV-then-convert workflow buys you crash resilience as well as multi-track headroom.
OBS ships the conversion step itself. Manually: File → Remux Recordings, pick your files, hit Remux. Automatically: Settings → Advanced → "Automatically remux to mp4", which OBS says will "remux your video as soon as you stop recording." Note what the documentation does not say — it uses the word "convert" throughout and never states whether the operation re-encodes, how long it takes, or whether your original file survives. Check the official documentation rather than assuming.
Try it right here
Runs in your browser. Your file is not uploaded anywhere.
Be clear about what the converter above is for. It runs in your browser and writes an MKV, but it re-encodes to H.264 video and a single AAC audio track — so it is a compatibility fix for a one-track file, not a way to move a six-track recording into a new container with its tracks intact. The rest of the browser tools are at Clapr tools; the container trade-off is unpacked further in MKV or MP4 for OBS recordings.
Gotchas worth knowing before you record
- Standard players only play one track. OBS states it directly: "all standard video players will only play back one audio track at a time so if you are not planning on processing every video through an editor before publishing it, send all of your audio sources to track 1." A multi-track file is for an editor, not for a preview window.
- Advanced view is where you choose which tracks get recorded, which OBS notes "can be helpful if you have, for example, copyrighted music in your stream that you don't wish to have recorded."
- Hybrid MP4/MOV are a separate thing from plain MP4/MOV. Introduced in OBS 30.2 and 32.0 respectively, they are written fragmented and then finalised by what OBS calls a "soft-remux." Audio support differs: Hybrid MP4 takes AAC, Opus, FLAC and ALAC, and lists PCM with a caveat — "PCM in MP4 is a relatively recent addition to the standard, and not supported in all applications. Hybrid MOV may provide better compatibility." Hybrid MOV takes AAC, ALAC and PCM.
- OBS's own pages disagree about the default container. The formats guide calls MKV "the default container," and the same page labels Hybrid MP4 as the Windows/Linux default and Hybrid MOV as the macOS default. Check what your build actually shows in Settings → Output rather than trusting either sentence.
- Extraction tools usually read track 1 only. Our audio extractor maps the first audio stream by design, so it can confirm what is on track 1 but cannot pull track 3 out for you.
FAQ
What recording format should I use in OBS for multiple audio tracks? MKV. OBS suggests it by name — "We suggest using mkv (you can remux later to mp4)" — and describes it as compatible with every codec combination OBS can produce.
Does MP4 support multiple audio tracks in OBS? OBS's documentation does not answer this. It says only that not all containers allow multi-track audio, and names FLV as single-track. No per-container track counts are published, so check the official documentation rather than a number from a blog.
How many audio tracks can OBS record? Up to 6, per OBS's advanced recording guide — see the track limit in detail. Those options live in Advanced Output Mode.
I enabled six tracks but my recording still has one. Why? Most likely you assigned sources in Advanced Audio Properties but never enabled the tracks in Settings → Output. They are two separate screens and both are required.
Why does my multi-track recording sound silent in VLC or Windows Media Player? Because standard players read a single track, and your sources may all be on tracks the player is not reading. OBS's fix is to keep a full mix on track 1.
Can I convert my MKV to MP4 and keep all six tracks? OBS's documentation does not state this. It documents File → Remux Recordings as a way to convert a non-MP4 recording to MP4, but never says what happens to the audio tracks — check the official documentation. Browser-based converters, ours included, output a single audio track.
All quotations are from OBS Studio's own knowledge base — its guides on multi-track audio, audio/video formats, standard recording output and Hybrid MP4/MOV — checked 16 September 2026. Start at OBS's help portal for current versions. More spec write-ups in limits.
