OBS Studio’s Replay Buffer keeps a rolling portion of recent footage so you can save a short clip after something happens. To use it, enable the buffer in Output settings, set a duration, assign start and save hotkeys, and start buffering before the moment you want to keep.
The buffer is not a substitute for continuous recording: it only retains footage while it is running, and it needs enough system resources to do so. Test the complete workflow on your own OBS version and output mode before relying on it for a live event or an important capture.
What OBS Instant Replay Does
Replay Buffer continuously holds recent output for the duration you choose. When you use the Save Replay Buffer action, OBS writes the currently buffered portion as a clip. As new footage enters, older footage falls out of the rolling window unless it has been saved.
Think of it as a short, moving window rather than a recording that can be rewound indefinitely. If you set a duration of a few minutes, the buffer can retain roughly that window of recent footage while active. It cannot recover a moment from before you started the buffer, and it cannot save a clip if the buffer was stopped or failed to start when the moment occurred.
This is useful when you are streaming a live game, a music session, a class, or a community event and do not want to record the entire session. For example, if a guest says something worth keeping, you can press the save hotkey shortly afterwards and review the resulting clip. If you need a complete archive, start a normal recording as well; Replay Buffer is designed for selected moments, not guaranteed continuous coverage.
OBS settings and available controls can vary with version, operating system and output mode. Use the labels shown by your installed copy as the source of truth. OBS’s Studio overview describes the Replay Buffer workflow and the need to set a save hotkey.
Enable the Replay Buffer
Open Settings → Output in OBS Studio and look for the Replay Buffer option. Enable it, then review the controls OBS presents for your current output mode. Depending on the installed version and configuration, the location or available fields may differ, so do not assume a tutorial for another version will match every label on your screen.
If OBS presents recording or encoder settings alongside the buffer controls, treat them as consequential rather than cosmetic. The replay output uses an encoder and quality settings, and that work adds load to the computer. If you already run a demanding game, browser sources, animated overlays, or high-resolution scenes, a replay buffer can compete for resources.
Choose a recording path that you can recognise later. OBS provides a recording path in Output settings; check that it points to a folder with space and that you have permission to write there. A dedicated folder such as Videos/OBS-Replays is easier to check than a general downloads folder, provided you actually select it in OBS.
Before changing several settings at once, note the current values or take a screenshot. Then enable the buffer and apply the change if OBS asks you to. A short test clip after setup is more useful than assuming that an enabled checkbox means the whole workflow is ready.
Choose a Duration and Output Settings
Pick a duration based on what you are likely to need, then test it. A short buffer uses less memory than a long one, while a longer window gives you more time to notice a moment and save it. There is no single duration that suits a brief spoken answer, a long musical transition and an entire class demonstration equally well.
The duration is a trade-off, not an archival setting. A longer window and more demanding quality can increase resource use; if OBS cannot start the buffer or remains unstable, reduce the duration or output demand and test again. Do not copy an exact memory estimate from a forum post as if it applied to your computer. Available memory, encoder, resolution and other active applications all affect the result.
| Decision | What you gain | What to check |
|---|---|---|
| Shorter duration | A smaller recent window and generally lower resource demand | Whether it is long enough to notice and save the moment |
| Longer duration | More time to react and more footage before the save press | Whether OBS starts and remains stable on your setup |
| Higher recording quality | More detail in the saved clip | Encoder load, file size and playback in your intended editor |
| Keyboard hotkeys | A direct control without extra hardware | Key conflicts with games, applications or other OBS actions |
| Optional physical control | A tactile button can be easier to reach | Current device, plugin and software compatibility |
The OBS Project’s standard recording output guide recommends MKV for recordings because an ungraceful stop is less likely to corrupt the whole file. Do not assume every Replay Buffer setup writes the same format: check the actual output settings and resulting file in your installed OBS version. If you plan to edit the clip, test it in the intended editor or player before an event.
One version-specific detail is worth keeping in context. OBS Studio 29 release notes stated that the Replay Buffer memory limit was changed to 75% of installed system RAM rather than a fixed 8 GB. That documents a change for that version, not a universal memory recommendation or a guarantee about current behaviour; check the release notes and controls relevant to the OBS version you use.
Assign Start and Save Hotkeys
Open Settings → Hotkeys and find the Replay Buffer actions. Assign a key or key combination to Start Replay Buffer and a separate one to Save Replay Buffer. The exact names may vary, so look for the equivalent actions in your version rather than mapping a key to a similarly named recording control by mistake.
These actions do different things. Start Replay Buffer begins retaining recent output; Save Replay Buffer writes a clip from the footage the buffer currently holds. Starting the buffer does not itself create a replay file, and pressing save cannot bring back footage from before buffering began.
Choose combinations that you can press reliably without disrupting your normal controls. If you are gaming, avoid a key used by the game. If you are presenting, choose something you can reach without switching windows or losing your place. Check the rest of the Hotkeys page for conflicts, and avoid assigning the same combination to unrelated actions.
A keyboard is sufficient. An optional Stream Deck or other physical controller may be convenient if you need a dedicated button, but it is not a requirement. If considering a device, confirm that its current software and OBS integration work with your setup; do not assume an older guide applies to every model or version.
After assigning keys, save or apply the settings. Write them down or keep a reminder near the streaming controls until they become familiar. A hotkey that is technically assigned but forgotten during a live moment is no more useful than an unassigned one.
Start Buffering Before the Moment
Start Replay Buffer before the part of the session you may want to keep. Use the assigned Start Replay Buffer hotkey, or the corresponding control in OBS if available, and make sure OBS indicates that the buffer is running. Do not wait until after an interesting moment: the buffer does not capture backwards from the instant you turn it on.
If you want the buffer to start whenever OBS opens, OBS documents the --startreplaybuffer launch parameter. Its launch parameters guide describes ways to pass the parameter, including a Windows shortcut and macOS launch methods. This can reduce the chance of forgetting, but it does not remove the need to confirm the buffer is actually running after OBS starts. Launch behaviour can depend on how you open OBS, so test the method you intend to use.
A simple routine helps: open OBS, check the correct scene and sources, start the buffer, and confirm its status before beginning the activity you want to capture. If you restart OBS, change settings, or switch to a configuration that affects the output, check the buffer state again. Treat any restart as a reason to verify rather than assume it resumed.
For a channel where OBS must also keep a stream connected through a network interruption, replay saving and reconnection are separate problems. The practical checks in this guide to OBS reconnecting after an Indian broadband outage address a different failure mode; they do not replace checking that Replay Buffer is active.
Save and Find a Replay
Once the moment has happened, press Save Replay Buffer. The save action asks OBS to write the buffered portion to a file. It may take a little time to finish, particularly if the clip is long or the system is busy, so do not immediately close OBS or assume that the key press failed. Watch for an OBS status message or check the destination folder after a brief pause.
Find the recording path under Output settings and open that folder directly. If the file is not where you expected, check whether you changed the path, whether OBS was configured with a different profile, and whether the folder is writable. Use a recognisable folder name and make a small test save before you need a clip in a hurry.
Play the test file from beginning to end, or at least sample its start, middle and end. Check that the video plays, the expected audio is present, and the clip contains the moment you intended. If you use multiple audio tracks or sources, confirm which of them were included rather than assuming a replay mirrors every monitoring or streaming choice.
File format and editor compatibility are practical parts of the test. Follow OBS’s current recording guidance, then verify the replay file that your own configuration produces. If an editor does not accept it, investigate the format and conversion workflow before an event rather than changing output settings at the last moment. The HEVC-to-H.264 conversion guide for OBS playlist streaming is relevant if your source footage is HEVC, though it does not configure Replay Buffer itself.
If the purpose is to keep every minute of a programme, use continuous recording and check that recording separately. For a long-running YouTube channel built from existing files, a replay buffer is not the same as a scheduled or looping broadcast. This guide to looping prerecorded videos on YouTube Live from Linux covers that distinct workflow.
Troubleshoot Missing Replays
When a replay does not appear, work through the chain from capture to file rather than changing everything at once. First confirm that Replay Buffer was enabled and started before the moment. Then check that the Save Replay hotkey is assigned to the intended action and that you pressed that combination. Starting or stopping the buffer alone does not write a clip.
Next, verify the destination path in the active OBS settings and look there directly. Check for a changed profile, an unexpected folder, a full drive, or a folder that OBS cannot write to. Search for recently created files if you are unsure of the exact name, but avoid concluding that a save failed solely because you checked the wrong directory.
If the buffer will not start or OBS becomes unstable, reduce the duration and output demands, close unnecessary applications, and test again. Replay Buffer consumes system resources while active; encoder availability and load depend on the computer. OBS Studio 29’s memory-limit note is version-specific, so it is not a sound basis for assuming a particular amount of free RAM will always be enough.
If a file exists but appears broken or incomplete, test it in another player and review the output format. OBS recommends MKV for recordings because it is less vulnerable to whole-file corruption when a recording stops ungracefully, but confirm what your Replay Buffer actually saved. A successful save still needs an intact file and playback check before you depend on it.
Finally, distinguish a missing replay from a stream interruption. OBS may be live while the local replay save has a separate problem, and a local replay can save even when the stream itself has a network issue. If you run an always-on prerecorded channel, the task of keeping the broadcast alive is different from retaining selected local moments. StreamNeo is useful when the specific burden is leaving your own computer on to keep an uploaded video streaming continuously, rather than capturing occasional clips with Replay Buffer.
Build a Test into Your Routine
Before a real session, do a complete rehearsal with the scene and audio sources you will use. Start the buffer, wait long enough to produce a short clip, press Save Replay, locate the file, and listen and watch it. This verifies the hotkey, active buffer, output path, codec handling and audio routing as a chain, instead of checking each control in isolation.
Repeat that check after an OBS update, a settings change, a new profile, a changed encoder, or moving the recording folder. A setting can look correct while a changed output configuration alters behaviour. Keep the test modest and repeatable so it does not require a long rehearsal each time.
If other people operate the channel, give them the two hotkeys and the path, and explain the difference between starting the buffer and saving a replay. For an event, decide who is responsible for pressing save and who is monitoring the stream. Clear responsibility matters more than adding extra controls that nobody has tested.
If the clip matters beyond a quick share, copy it to your normal storage location after confirming playback. Replay Buffer is a convenient capture mechanism, not a backup strategy. If the computer loses power, the drive fills, or the clip is never saved, the rolling window should not be treated as a permanent archive.
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FAQ
Does Replay Buffer save everything that happened earlier?
No. It retains recent footage only while it is running, so start it before the moment you want to capture. It cannot recover footage from before it was started.
Why does starting the buffer not create a file?
Starting begins the rolling capture; the separate Save Replay Buffer action writes a clip. Assign and use a save hotkey, then check the configured recording path for the resulting file.
Can Replay Buffer replace a full recording?
No. It is for saving selected recent moments, not for keeping a complete programme. If you need every part of a session, run and test continuous recording separately.
What should I check if OBS will not start the buffer?
Try a shorter duration or less demanding output settings, then check whether OBS can run stably with your other applications and sources. Resource use depends on the computer, encoder, settings and OBS version, so verify the result with a short test rather than relying on a general memory estimate.