For a single video that you want to loop in OBS, MP4 containing H.264 video and AAC audio is a sensible compatibility-first choice. It is not a uniquely best OBS format: OBS supports several containers, and the actual codec combination must still decode correctly on your installed OBS version and playback hardware.
Add the clip as a Media Source, select Loop, and test it in the scene you will use. The file format does not set the live stream's resolution or frame rate; configure those separately in OBS and check whether your system can play and encode the intended 4K60 output reliably.
Short answer: choose for compatibility, then test
If you are preparing one ordinary local video for a loop, start with MP4, H.264 video and AAC audio. That pairing is a practical default because OBS describes MP4 as a de facto internet-video standard, H.264 as ubiquitous and AAC as widely supported. Those descriptions make it a reasonable place to begin, not a guarantee that every MP4 will work on every machine.
A filename ending in .mp4 tells you the container, not exactly which codecs are inside. A file can use a codec your OBS build or hardware does not decode smoothly, even when its extension looks familiar. Check the video and audio codecs, then play the actual file in your installed OBS setup rather than treating the extension as proof.
For a single repeating clip, OBS already has a loop control in its Media Source properties. You do not need a playlist source merely to repeat one video. If the programme is a changing playlist, that is a different workflow; a source such as VLC Video may be useful, with the additional VLC installation requirement.
This article is about preparing and looping the source. It does not prescribe YouTube ingest bitrate, keyframe interval, or account settings: check YouTube's current official guidance for those platform-specific requirements rather than inferring them from the local file format.
Container, codec and stream output are different things
A container is the file wrapper that holds video, audio and associated information. MP4, MKV, MOV and WebM are examples. A codec is the method used to encode or decode a particular stream inside that wrapper. H.264 and AV1 are video codecs; AAC is an audio codec. The same container extension does not promise that the contents use the same codecs.
That distinction matters when troubleshooting. If OBS can open a file but playback is black, stutters, or has no sound, “it is an MP4” is not enough information to identify the problem. Find out what video and audio codecs are inside it. Then check whether the version of OBS and the playback device can decode them. OBS's Audio/Video Formats Guide maps common codecs to containers and discusses their compatibility.
A third setting is the live output. OBS's canvas, scaled output resolution and common FPS value determine how the scene is composed and sent for encoding; the source file does not select those settings for you. A 4K60 file placed in a 1080p30 scene remains a source in that scene, not an automatic instruction to broadcast at 4K60. OBS explains the separate output controls in its Studio Overview Guide.
For example, suppose your scene contains a 4K clip but your intended stream output is 1080p. OBS has to decode the source and scale it for that scene. If the visible clip is small, a lower-resolution source may be adequate and lighter to process. Conversely, if the stream itself is intended to show 4K detail, scaling a smaller file up will not create that detail. Match the source to its displayed size and intended output where practical.
Formats OBS supports and what they mean in practice
OBS lists MP4, TS, MOV, FLV, MKV, AVI, GIF and WebM among supported video file types. Support for a container is not the same as a promise that every codec combination in that container will decode on your particular system. Compare the actual contents and workflow needs, not just the extension.
| Choice | When it is a reasonable fit | What to check |
|---|---|---|
| MP4 with H.264 video and AAC audio | One local clip where broad compatibility is the priority | Confirm the actual codecs and test playback in the installed OBS build |
| MKV | A source file already supplied in MKV, or a workflow where that container is otherwise useful | Do not assume recording resilience makes it necessary for a loop source; check its codecs |
| MOV | A file delivered from an editing workflow, including some Mac-oriented workflows | MOV can contain different codec combinations; verify that your playback setup handles yours |
| WebM, AVI, TS, FLV or GIF | A specific existing asset or workflow calls for it | Confirm codecs, audio behaviour and successful playback before relying on it |
| VLC Video source | A playlist or a source workflow that benefits from VLC library support | VLC must be installed; a single Media Source can loop without it |
The table is a starting point, not a ranking. OBS describes MKV as flexible across its recording encoders and resilient if a recording ends unexpectedly. Those are useful recording properties, but they do not make MKV the required or preferred container for a looping source. MOV can suit editing workflows and is often favoured on Mac platforms, but the codec still matters. Use the file you can decode reliably, rather than converting solely to adopt a fashionable extension.
AV1 and HEVC are also codecs you may encounter, but their suitability depends on the combination of container, OBS support and hardware decoding available on the playback machine. They are not needed to make the basic loop work. Unless you have a reason to choose them and have tested support on the actual setup, a compatibility-first H.264 file is simpler to evaluate.
If your content is a playlist rather than a single long clip, use the source type that fits that job. OBS's Media Sources instructions describe Media Source properties, including Loop, and the VLC Video source's playlist controls. For a channel built around a changing sequence, a playlist filename overlay in OBS may also help viewers understand what is playing, but it does not change codec compatibility.
Add the file as an OBS Media Source
Open the scene that should contain the video and add a Media Source. Give the source a recognisable name, then choose the local file in its properties. If you have several scenes or versions, a name such as “Main loop – 4K master” is clearer than leaving multiple items as “Media Source”. Keep the file in a stable location; moving or renaming it later can leave the source pointing at a path that no longer exists.
For a single clip, enable Loop in the Media Source properties. OBS defines Loop as specifying whether the file plays again once playback has completed. With that setting on, the source starts its playback cycle again at the end. You can restart playback as needed while preparing the scene, but first verify the loop boundary itself: there should not be an unintended black frame, audio gap, or abrupt jump that is part of the source edit.
There are other properties that can affect how a source behaves, including whether it restarts when it becomes active and whether it is visible. Use the options that suit your scene transitions; do not change several at once while diagnosing a playback problem. The OBS Media Sources guide is the primary reference for the controls in the source properties, and names may differ slightly with version changes.
If you need to rotate through many files, consider VLC Video rather than adding one Media Source per item. OBS says this source relies on VLC libraries and requires VLC to be installed; its properties include Loop Playlist. That adds a dependency and a different workflow, so for one repeated video it is usually unnecessary. For a playlist channel, first test the sequence and transitions; a guide to running a 24/7 Hindi remix stream with OBS covers broader operational considerations beyond the file container.
Enable looping and test playback
Before relying on the scene, watch at least one complete playback cycle in OBS. Confirm that the opening frame appears, the picture remains visible, the audio is present if expected, and the transition from the final frame back to the beginning is acceptable. A file can be technically looped while still having an edit that makes the join distracting.
Check the sound separately. If the source should have audio, listen for it in the OBS mixer and monitor the beginning and loop point. If the video is intentionally silent, make sure the scene's other audio sources are not masking a mistaken assumption that the file includes sound. An MP4 extension does not tell you whether an audio stream is present or which audio codec it uses.
Then test the scene at the intended output settings, not only in a file player. OBS must decode the source, composite the scene and encode the live output. A clip that plays acceptably in a desktop player may behave differently when OBS is also scaling, rendering overlays and encoding. Watch the OBS preview and relevant status indicators while the clip runs; do not assume that one successful start proves it will remain smooth through a long session.
Keep a known-good copy of the original media file before experimenting with conversion or re-encoding. Change one variable at a time: try the original file, then if needed test a different codec combination or a lighter source resolution. That way you can tell whether an improvement came from the source file, the output settings, or a change in scene workload. For long-running channels, also plan how you will notice a stalled picture or dropped output; a discussion of monitoring a 24/7 stream while away is relevant to operations, but monitoring cannot repair an incompatible file.
Check decode compatibility on your setup
The right test environment is the OBS installation and computer or hosted machine that will actually run the channel. Verify the OBS version, the file's video and audio codecs, and whether the available decoder can handle them. If a file fails, do not immediately conclude that OBS cannot loop its container: a codec, damaged media, unavailable decoder or resource constraint may be the cause.
OBS offers Use hardware decoding when available for Media Source. It is optional. It can be worth testing when the GPU has an appropriate built-in decoder, but do not enable it on the assumption that any GPU can decode every format or that a separate decoder device is needed. Compare playback with the setting on and off on the target system. Keep the choice that behaves reliably there.
Resolution and frame rate affect workload. OBS cautions that 60 fps can be more taxing than 30 fps. A 4K60 source can demand more decoding and rendering work than a smaller or lower-frame-rate clip, particularly when other scene elements and encoding are active. OBS's Encoding Performance Troubleshooting discusses reducing output resolution or frame rate when performance is overloaded and avoiding unnecessarily high-resolution media sources when they are scaled down or the stream is not 4K.
That does not mean every 4K60 loop needs to be reduced. If the scene is meant to deliver that detail and your test remains smooth, keep the quality you need. If the source fills only part of the scene or your intended output is lower resolution, a smaller source may meet the visual requirement with less work. Choose based on the actual displayed size and output, then test during the kind of scene activity you expect in production.
Keep source decoding separate from stream encoding in your diagnosis. A source may decode smoothly while the encoder struggles, or the source itself may stutter before output encoding is involved. Check the OBS performance guidance and stats to identify whether rendering or encoding is overloaded, then adjust the relevant workload rather than changing containers at random. Reducing output FPS or resolution is a trade-off in motion smoothness or detail; test the result against what viewers need.
Keep file settings separate from YouTube settings
The source's MP4 container and H.264 video do not guarantee that the YouTube broadcast will be 4K60, accepted, or stable. Set the OBS base canvas, output (scaled) resolution and Common FPS Value deliberately for the stream you intend to send. OBS says the Common FPS Value should match the desired output FPS, with 30 and 60 as examples. It is an output choice independent of how the source file is packaged.
Do not infer YouTube-specific ingest settings from a local-file recommendation. Platform requirements and account capabilities can change, so consult the current official YouTube Help or developer guidance for resolution, codec, bitrate and keyframe recommendations before configuring a live encoder. This article does not provide a bitrate figure because the gathered OBS material does not establish a current YouTube-specific setting.
If your goal is a 24/7 channel, also decide what should happen after a computer restart, network interruption or OBS failure. OBS on your own machine puts playback and broadcasting responsibility on that machine and its power and network connection. A cloud-running workflow can remove the need to leave that computer on for the broadcast; StreamNeo takes an uploaded video and your YouTube stream key so you do not have to keep a local OBS session running for a single-file channel, while still leaving YouTube setup and content decisions with you.
The choice between local OBS and another workflow is about who maintains the running session, not about whether MP4 is technically required. If you need custom scenes, live switching or a playlist assembled from changing sources, OBS may remain the natural fit. If the channel is simply one prepared video on repeat, compare the operational burden of keeping the local machine running with the alternatives, and test whichever arrangement you choose before depending on it overnight.
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
What format should my looping video be in for OBS?
For one local clip, MP4 with H.264 video and AAC audio is a practical compatibility-first starting point. OBS supports multiple containers, so this is not a special requirement or guarantee. Confirm the actual codecs and test playback in the OBS version and on the hardware you will use.
How do I loop a video in OBS?
Add the local file as a Media Source, open its properties and enable Loop. Play through the end and beginning in OBS to check both picture and sound at the join. For a playlist, investigate VLC Video and its playlist controls instead of treating a single-file loop as a playlist feature.
Does an MP4 file guarantee 4K60 YouTube Live output?
No. The extension does not guarantee a particular codec, successful decoding, or a 4K60 live output. Configure the OBS canvas, scaled output resolution and FPS separately, check the system's performance, and verify current YouTube ingest guidance on its official pages.
Should I use hardware decoding for a 4K60 source?
Only if the playback machine has a suitable built-in decoder and testing shows that enabling the Media Source option helps. It is optional, and support depends on the codec and hardware combination. Compare playback in your actual scene with the option on and off before relying on it.