There is no published maximum local video-file size for playing a pre-recorded video in OBS as a Media Source and sending it to YouTube Live. OBS reads and decodes the file on your computer; YouTube receives the encoded live stream, not that source file.
In practice, a large source is limited by local storage, the computer’s ability to read and decode it, stream duration and the capacity of your internet connection. Those are practical considerations inferred from the documented workflow, not a YouTube guarantee or a stated file-size allowance.
No documented maximum for a local OBS source
The OBS and YouTube documentation reviewed does not give a maximum size for a local video used as an OBS Media Source in a YouTube Live broadcast. That means there is no official number to compare your file against. It does not mean that every file, on every computer, will play reliably: a file can fit on disk yet still be difficult for a particular machine to decode or keep playing smoothly.
The key is to distinguish two operations. With a Media Source, your computer opens the video and OBS uses its pictures and sound in the live programme. With a direct upload, you send the finished video file to YouTube through YouTube Studio. The platform’s guidance for the second operation does not establish a size cap for the first.
If you are asking whether a 20 GB, 50 GB or larger local source is allowed, the careful answer is that the reviewed documentation gives no local-source maximum. Whether it is practical depends on what is available on your system and whether it can play the file for the intended duration without interrupting the outgoing stream. Treat any specific maximum you find for a different workflow as a different limit unless the documentation explicitly says it applies to OBS Media Sources.
This distinction is useful when planning a devotional loop, a study channel or a local news programme. A long programme can be a large file, but its size alone does not tell you whether the stream will be stable. Test the actual file and live settings rather than using an upload figure as a substitute for that test.
How OBS reads a Media Source
An OBS Media Source is a playback source within your scene. OBS reads a local file, decodes its video and audio, and includes the resulting output in the programme it sends to YouTube. The file remains on your computer; it is not uploaded to YouTube merely because OBS is playing it.
The OBS Project’s Media Sources documentation lists common formats such as MP4, TS, MOV, FLV, MKV, AVI, GIF and WebM. It also describes playback controls, including looping and restarting when the source becomes active. The page does not publish a maximum file size or duration. A listed format is not a promise that every file using that extension, codec or encoding will decode smoothly on every computer.
For example, two files can both be MP4s but put very different demands on a computer. Resolution, frame rate, codec, bitrate, audio tracks and the way the video was encoded all affect the work involved in reading and decoding it. A file’s size is mainly a measure of how much data is stored; it is not a direct measure of how hard it will be to play at a given moment.
Check playback in the same scene and configuration you intend to use. If the Media Source is meant to loop, enable that behaviour and check the transition at the end. If the broadcast uses other sources, such as a logo, lower third or browser-based information panel, test with those active as well. The pre-live checklist is useful for checking the whole scene rather than only confirming that the video opens.
A common misunderstanding is to treat the file as though OBS must first load all of it into memory. In normal playback, the source is read and decoded as the programme runs; the practical question is whether the computer can sustain that work, not whether it can hold the entire video in memory at once. Still, storage speed and available space matter, especially if the file is being copied, recorded or accessed from a drive shared with other work.
What YouTube receives from a live stream
When OBS streams, YouTube receives the outgoing encoded live programme. It is the result of playback and any other scene elements, converted to a stream using chosen encoder settings. YouTube’s live encoder guidance discusses ingest protocols, codecs, frame rates, keyframes and bitrates for that outgoing stream.
Those stream settings describe the data sent over your connection, not the size of the source file stored on your computer. You might have a very large source file but send a stream at a modest bitrate; conversely, a relatively small source can still be encoded and sent at a higher bitrate. The source-file size and outgoing bitrate are different measurements serving different purposes.
For H.264, YouTube’s current guidance gives recommended live ingest bitrates of 14 Mbps for 1080p at 30 frames per second and 17 Mbps for 1080p at 60 frames per second. These are live-stream recommendations, not source-file requirements or size limits. If your source is 1080p, that fact alone does not force a matching source file size or determine the stream bitrate; encoder configuration and the content also matter.
The distinction helps diagnose symptoms. If YouTube reports poor stream health or viewers see buffering, look at the outgoing stream, encoder load and upload connection. If OBS stutters while the Media Source plays, investigate local decoding, storage access and scene workload. A large file may prompt you to check both sides, but size by itself identifies neither cause.
Practical limits: storage and decoding
Start with the simple local constraint: enough free space on the drive to store the file and keep the system operating normally. If you are still downloading or copying the video, allow space for any temporary copy or intermediate file your workflow creates. Check that the drive is available and does not go to sleep or disconnect during the broadcast. These are operational checks, not published OBS or YouTube size rules.
Next, consider decoding. Higher resolution, higher frame rate or a demanding codec can ask more of the computer than a lower-demand source. OBS has to decode the frames in time for the broadcast, while also encoding the outgoing programme and handling any other active sources. A source that plays perfectly in a media player may behave differently when OBS and the stream encoder are working at the same time.
Watch OBS’s performance indicators and the stream health feedback while testing. If frames are missed or the picture freezes, reduce the workload methodically: close unrelated applications, simplify the scene, test a lower output resolution or frame rate, or use a source file encoded in a format your computer handles more comfortably. Change one thing at a time so you can identify the cause instead of guessing.
If the source is on an external drive, test with that drive and cable connected as they will be during the broadcast. If the file is stored on a network location, confirm that the connection remains available and responsive. Moving the file to a local drive can eliminate a network read as a variable, but it requires enough local space and does not automatically solve a decoding bottleneck.
Also consider the rest of the machine’s workload. A computer used for browsing, editing, file transfers and OBS at once has less capacity available than one dedicated to the broadcast. A spare PC may be perfectly adequate for a straightforward looping video, but the answer depends on the source and scene. The overnight OBS setup guide covers the broader question of keeping a local computer working through a long run.
Duration, bitrate and upload capacity
The source duration affects how long OBS must keep playback working, while the outgoing bitrate affects the data your connection must upload continuously. Neither is a direct conversion of the other. A two-hour source can be large or small depending on how it was encoded; the live broadcast can continue beyond that duration if the source is set to loop, but the stream still needs a stable connection.
YouTube advises leaving upload headroom beyond the selected stream bitrate and notes that shared networks can affect the capacity available to your broadcast. Its streaming tips recommend a speed test and preparation before starting. The useful measurement is sustained upload performance at the place and time you will stream, not just a headline speed from a different network condition.
For illustration, the H.264 recommendations above mean a connection needs to sustain more than the stream’s target bitrate to leave room for variation. YouTube’s guidance recommends 20% beyond the stream bitrate; treat that as network headroom guidance, not a guarantee that the connection will remain stable. Other people using the same connection, Wi-Fi interference and background uploads can consume that room.
Duration raises a separate archive concern. YouTube says it can automatically archive a live stream that is less than 12 hours; streams exceeding 12 hours may not be captured at all. This is guidance about the live broadcast archive, not a maximum source duration or file size. If you need a complete recording of a long programme, plan and test a separate local recording rather than assuming the platform archive will preserve everything.
A file intended to run continuously should also be checked at the point where it loops or ends. Verify that sound does not drop, the scene does not go blank, and the source restarts as expected. If your plan involves manually restarting a stream or splitting it into sessions, account for transitions and archive needs in advance.
Why direct upload limits are a different question
Uploading a finished video through YouTube Studio sends the file itself to YouTube for processing and playback on demand. YouTube’s recommended upload encoding settings describe that direct-upload workflow. They should not be repurposed as an OBS Media Source maximum: in a live broadcast, OBS reads the local source and sends an encoded stream instead.
This matters because search results may combine answers about “YouTube video upload size” with answers about streaming through OBS. Even if an upload page sets conditions for a direct upload, that tells you about sending a file for YouTube to process, not about the local file OBS can open. Likewise, live encoder bitrate recommendations tell you how to configure the outgoing stream, not how many gigabytes a source can occupy.
Before relying on a limit, identify which step it applies to: storing a file on your computer, opening it in OBS, sending the live stream, or uploading a completed video in Studio. If you are uploading a large source to a remote workflow before streaming, then upload capacity and any applicable upload rules become relevant to that separate transfer. The large-file upload guide addresses that transfer question; it does not turn upload guidance into an OBS playback cap.
YouTube’s eligibility requirements for live streaming are also separate from file size. A channel must meet the platform’s current requirements, including verification and having no live-streaming restrictions in the preceding 90 days. Check YouTube’s live streaming eligibility page for current requirements before planning a broadcast. Eligibility does not establish that a particular source file will play well.
Test a large source before going live
Do a rehearsal with the exact file, scene, output resolution, frame rate and encoder settings planned for the real broadcast. A quick preview is useful for spotting a wrong aspect ratio or missing audio, but a longer test is more informative for a large source: it can reveal heat, resource pressure, drive interruptions, loop problems or upload instability that do not appear immediately.
Begin by checking the entire source in OBS. Confirm that the audio track is audible, the picture is correctly framed, and the source behaves as intended at the end. If looping, watch the transition. If the programme uses playlists or multiple files, test the change between them as well as each file in isolation.
Then test the outgoing stream using YouTube’s stream health information. YouTube recommends testing before starting and monitoring the broadcast. Keep an eye on OBS’s rendering and encoding status alongside YouTube’s feedback; the two can point to different problems. A clean local preview does not prove that the upload connection is stable, and a healthy connection does not prove that the computer can decode the file without dropped frames.
If you plan a long-running channel but do not want your own computer to stay involved in playback and streaming, that is a different operational choice from increasing the local file-size allowance. StreamNeo removes the specific need to leave your computer running by taking an uploaded video and running it as a YouTube live stream, so you do not have to keep OBS playing the source locally.
For a local OBS workflow, write down the tested settings and keep a copy of the source in a known location. Check that the computer will not sleep, that power settings will not interrupt the session, and that there is enough disk space if OBS is also recording locally. The 24/7 stream cost comparison can help when you are weighing a continuously running local setup against other operating arrangements, but it does not change the technical limits of the source file.
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
Is there a maximum file size for an OBS Media Source?
The OBS and YouTube documentation reviewed does not publish a maximum local source-file size for this workflow. The practical question is whether your storage and computer can sustain playback and whether the live stream has enough upload capacity.
Does YouTube’s upload limit apply to a video played through OBS?
No. Direct uploads through YouTube Studio and live streams sent by OBS are different workflows. Upload guidance applies to the file submitted for processing; OBS reads its local source and sends an encoded live programme.
Will a bigger source file make my live bitrate higher?
Not by itself. Source-file size describes stored data, while live bitrate is an encoder setting for the outgoing stream. Choose stream settings for the output quality and connection you can sustain, then test the actual source in OBS.
Can I stream a source longer than 12 hours?
The 12-hour caveat in YouTube’s guidance concerns whether a live broadcast is automatically captured as an archive; streams exceeding that duration may not be captured at all. It is not a source-file size cap or a promise about playback duration, so plan any required recording separately and check current YouTube guidance.