If you are looping one local video in OBS, MP4 and MKV can both work. Add the file as a Media Source, enable Loop, and let the source repeat when playback ends; the container does not decide whether looping happens.
The more important distinction is between playback and recording. MKV is usually the safer container for recordings made in OBS, while MP4 is more widely accepted for editing and uploads. Neither choice replaces the separate encoder settings that YouTube receives during a live stream.
Looping a video in OBS Media Source
For a single file, use OBS's Media Source. Add a source to the scene, choose the video file, and turn on Loop. OBS lists both .mp4 and .mkv among the video formats supported by Media Source, so either can be suitable for a devotional video, an ambience scene, a local news loop, or a shop promotion.
The setting belongs to the source, not to the file extension. A file does not become loopable because it is MP4, and it does not stop being loopable because it is MKV. If the video reaches its end and Loop is enabled, OBS starts it again according to the source's playback behaviour.
For a practical test, create a blank scene with only the Media Source visible. Select the file, enable Loop, and watch at least one complete ending and restart. Check the first and last seconds for a visible flash, silence, a frozen frame, or an abrupt audio change. A technically successful loop can still be unpleasant to watch if the source itself has a hard cut at the join.
Several other Media Source properties can affect what you see during a long-running broadcast. Restart playback when source becomes active is enabled by default in the OBS guide. Show nothing when playback ends is also enabled by default, although a looping source should normally begin again rather than remain at the end. Close file when inactive is disabled by default; enabling it can reduce the resources held by a hidden source, but the file may need time to reload when the source becomes visible again.
Those controls are worth testing if your scene changes between several sources. They are separate from the MP4-versus-MKV decision. If a file disappears, reloads slowly, or starts at the wrong point, changing the container may not address the real cause.
If your project is a continuous channel rather than a single looping scene, first decide whether OBS is the right operating method. The practical choices are discussed in how to set up an always-on YouTube channel with prerecorded videos, including the difference between leaving a computer running and using a method designed for unattended playback.
A simple Media Source check
Before putting the source into an overnight stream, check these items:
- The file opens and plays from beginning to end outside OBS.
- The correct Media Source is selected in the scene.
- Loop is enabled.
- The source is visible for the whole part of the scene where it should play.
- The end-to-start transition has acceptable picture and sound.
- The computer can keep the file playing while OBS is also encoding and sending the stream.
Do not assume that a file's extension tells you everything about its contents. A container can hold different video and audio codecs, and a particular codec combination may behave differently on a particular computer. Test the actual file you intend to use.
MP4 and MKV both support looping
The direct answer to the looping question is therefore straightforward: for one local file in OBS Media Source, choose either MP4 or MKV if the file plays correctly in your setup, then enable Loop.
This is different from asking which format is best for an OBS recording. The same person may reasonably use an MKV recording format, remux that recording to MP4 later, and still use an MP4 or MKV file as a looping Media Source. These are separate jobs with separate priorities.
| Intended workflow | Practical choice | Reason |
|---|---|---|
| Loop one existing file in OBS | MP4 or MKV with Media Source Loop enabled | Looping is controlled by the source property, and OBS lists both formats as supported. |
| Loop a sequence of files | OBS VLC Video with Loop Playlist | This source is designed for playlists rather than one file. |
| Record in OBS for later editing or upload | MKV, then remux to MP4 if needed | MKV gives more protection against losing the whole recording after an interruption; MP4 is broadly compatible. |
| Stream a looping scene to YouTube | Loop the local source, then configure the outgoing encoder separately | YouTube receives the encoded live output, not a simple copy of the local container. |
The table is a workflow guide, not a claim that one extension is universally better. If an editor accepts MKV directly, you may not need a remux. If a playback application handles MP4 more reliably on your computer, MP4 may be the convenient source. The decision should follow the task and the observed behaviour of the exact file.
For a sequence, do not force several files into one long video merely to obtain looping. OBS's VLC Video source can hold a playlist, and its Loop Playlist option is enabled by default according to the OBS Media Sources guide. VLC must be installed for that source to be available; the guide notes that 64-bit OBS requires 64-bit VLC.
A playlist introduces its own checks. Confirm the order, filenames, transitions, and behaviour when one item is shorter than the others. If your channel rotates several prayer tracks, podcast episodes, or shop messages, watch the hand-off between at least two items before leaving the scene unattended. For a playlist-based channel, how to stream a church choir concert playlist on YouTube around the clock is a useful example of the operational questions involved.
When VLC Video is useful
Media Source is the simpler choice when you have one file and want it to repeat. VLC Video becomes useful when the source itself needs to manage a group of files. It can use a playlist and offers controls intended for sequential playback, including Loop Playlist.
This does not make VLC Video a more reliable answer for every stream. It adds another installed application and another layer to check. If VLC is missing, the source will not be available. If OBS and VLC have different bitness, the source may not work as expected. Install the version that matches your OBS installation, and confirm the source appears before preparing a long broadcast.
Use VLC Video when the playlist is the requirement, not simply because the word “loop” appears in the question. For one file, Media Source has fewer moving parts. For several files, a playlist source can be clearer than creating many Media Sources and managing their visibility manually.
Test the playlist as a viewer would see it
A playlist test should include more than confirming that every file opens. Let the first file finish, listen for the transition, and confirm the next item starts. Then test the point where the final item returns to the first. Look for differences in aspect ratio, frame rate, volume, or black frames.
If the files come from different editing projects, standardise them before building the playlist where possible. Consistent dimensions and audio levels make the live output easier to manage. They also reduce the chance that a transition problem is mistaken for an OBS or VLC problem.
For channels that need a repeating set of episodes or announcements, scheduling may be a better fit than one open OBS session. How to schedule a continuous prerecorded stream on YouTube covers a different operating pattern, but the same principle applies: decide whether you need source looping, playlist playback, or scheduled broadcasts before choosing a file format.
Choose a format for OBS recordings
Recording is where MKV usually earns its place. OBS recommends MKV for recording because an ungraceful stop is less likely to make the whole file unusable. A power interruption, system crash, forced restart, or other writing problem can happen before the recording has been properly finalised.
Ordinary MP4 and MOV need finalisation. If that final step is interrupted, the recording may not be recoverable in the way you expect. This is the main reason not to select MP4 merely because it is familiar or because YouTube recommends MP4 for uploaded videos.
OBS describes MKV as compatible with every audio and video encoder supported in OBS Studio, while also noting that some editing applications support it less well. That creates a sensible two-stage workflow: record in MKV, then remux to MP4 when an editor or upload destination needs MP4.
MP4 remains useful when direct compatibility is the priority and the recording environment is controlled. For example, if you are making a short recording while monitoring the computer and immediately need to open it in a particular editor, MP4 may be convenient. You are accepting a different interruption risk, not changing the way a Media Source loops.
YouTube's upload guidance specifies MP4 as its recommended upload container. That guidance applies to an uploaded file, not to the local file being repeated inside OBS. You can check the current recommendations on YouTube's recommended upload encoding settings before preparing a file for upload, because platform guidance can change.
If your recording contains several audio tracks, unusual codecs, or an editor with limited container support, check the editor's current documentation as well. A file that is structurally valid may still need a remux or a compatible export before the editor can use it comfortably.
What about Hybrid MP4
Recent OBS versions also document Hybrid MP4 and Hybrid MOV formats. The OBS guide states that Hybrid MP4 was introduced in OBS 30.2 and Hybrid MOV in OBS 32.0. These formats aim to combine recovery characteristics associated with fragmented files with a finalisation step intended to retain compatibility with software that accepts regular MP4 or MOV.
Do not assume that every installed OBS version offers the same choices. Confirm the available formats in your own installation and check whether your editing software accepts the resulting file. Hybrid formats may be useful for a specific workflow, but the basic recommendation remains easy to apply: use the recording format whose failure mode and compatibility suit the work you are doing, then test it.
Remux MKV to MP4 when needed
Remuxing changes the container around the existing audio and video streams. It is not the same as re-encoding the video, and it is not a reason to download a random conversion utility. OBS includes a remux workflow for this purpose.
After recording, open File → Remux Recordings in OBS, choose the MKV recording, and create the MP4 version. OBS also documents an Automatically remux to mp4 option that can perform the step after recording stops. Check the wording and location in the version you have installed, because interfaces can change.
The useful sequence is:
- Record the long session in MKV.
- Stop OBS normally when the session is complete.
- Remux the recording to MP4 if the editor or upload destination needs it.
- Open the resulting MP4 and check picture, sound, duration, and synchronisation.
- Keep the original MKV until you have confirmed that the remuxed file is usable.
Remuxing does not repair a bad source, fix missing audio, or make an incompatible codec compatible with every editor. It also does not turn a recording into the settings required for YouTube Live. It solves a container and workflow problem after recording.
If you need an MP4 for an upload, verify the finished file before deleting the source. A short test may not reveal a problem near the end of a long recording, so inspect the duration and, where practical, seek near the beginning, middle, and end.
Keep the local file separate from live ingest settings
A local looping file and the live signal sent to YouTube are two different parts of the system. OBS reads the file, places it in the scene, and encodes the resulting scene for live output. YouTube receives that outgoing encoded stream rather than relying on the extension of the file on your disk.
That means changing MKV to MP4 does not automatically change the live codec, bitrate, frame rate, keyframe interval, or audio settings. Conversely, adjusting those live settings does not decide whether an OBS Media Source repeats its file. Treat the source configuration and the output configuration as separate checklists.
YouTube's current live encoder guidance covers H.264, H.265/HEVC, and AV1 video, supports up to 60 frames per second, recommends a two-second keyframe interval, and says not to exceed four seconds. It also calls for CBR bitrate encoding and lists AAC or MP3 audio for RTMP or RTMPS. Use the current YouTube live encoder settings for the exact bitrate table and requirements for your chosen resolution, frame rate, and codec.
Do not copy an upload bitrate into a live stream simply because both workflows involve YouTube. Upload recommendations and live-ingest recommendations answer different questions. The live encoder settings must be applied in OBS's output and stream configuration, while the MP4 or MKV choice belongs to the local source or recording workflow.
For a 24/7 channel, test with representative motion and audio rather than a static desktop scene. YouTube recommends testing the setup and monitoring stream health. Watch the stream as a viewer, check for dropped frames and audio issues in OBS, and review YouTube's health indicators. A file can loop correctly while the outgoing connection or encoder struggles.
If you are working through bitrate and encoder choices separately, see how to set YouTube ingest bitrate for a 24/7 FFmpeg stream. The commands there concern a different tool, but the separation between local media and YouTube's ingest requirements is the same.
A reliable overnight test
Do not make the first full-night run the first time you test the exact file. Start with a short supervised broadcast or private test, depending on the audience and channel setup you use. Confirm that the source loops, the scene remains active, and the outgoing stream reaches YouTube with sound and motion.
Then test the failure points you can reasonably reproduce. Stop and reopen the source, change scenes, restart OBS, and confirm what happens after the computer resumes from sleep if sleep is part of your normal setup. Check whether a hidden source reloads with a delay when Close file when inactive is enabled.
For a long-running channel, also consider what happens when your local computer is unavailable. An OBS loop depends on the machine, power, operating system, internet connection, and the process that keeps OBS running. If the goal is to upload once and avoid leaving the computer on, StreamNeo removes that particular unattended-playback task by taking an uploaded video and running the YouTube broadcast without your computer, with monitoring and automatic restart when the broadcast drops.
That does not remove the need to check your media rights, YouTube account status, stream settings, or the behaviour of the actual content. It simply changes where the continuous playback task runs. For a comparison of other operating patterns, OBS vs FFmpeg for a nonstop YouTube event replay stream explains why the tool choice affects maintenance as well as playback.
Before committing, compare the operating options on the pricing page. When the file and channel are ready, start free — 24-hour trial, no card.
FAQ
Can OBS loop an MKV file?
Yes. Add the MKV as an OBS Media Source and enable Loop. Looping is controlled by the source setting, not by MKV itself.
Is MP4 better than MKV for a looping YouTube video?
Neither container is automatically better for a single loop in OBS. Choose the file that plays correctly in your setup, then test the complete end-to-start transition.
Should I record in MKV and upload MP4?
That is often a sensible workflow. Record in MKV for better protection against losing the whole recording after an interrupted stop, then remux it to MP4 when your editor or upload workflow needs that container.
Does the local file format control YouTube Live quality?
No. The local container and the outgoing live stream are separate. YouTube Live quality depends on the encoder settings sent by OBS, including codec, bitrate, frame rate, keyframe interval, and audio configuration.