Replay Buffer in OBS: How to Save the Last Minutes of a Stream

What Is Replay Buffer in OBS

Replay Buffer constantly holds a small segment of a local recording. When something interesting happens, you press Save Replay, and OBS saves the last seconds or minutes to a separate video file. After that, the buffer keeps running, so you can save the next moment too.

The feature is useful for gaming clips, standout moments from a stream, unexpected reactions, and short videos for social media. At the same time, OBS does not save the entire stream as a ready-made file. Until you press the save button, the program works with a temporary buffer, and a file appears only after the Save Replay command.

Replay Buffer is not connected to clips on Twitch or recordings on another streaming platform. It is created on the computer where OBS is running. So for it to work, you need free disk space, access to the save folder, and resources for local recording.

What to Check Before Enabling

First, make sure OBS sees the sources you need: the game, microphone, computer audio, or other scene elements. If the mixer indicators show no movement, Replay Buffer will not add that sound to the saved clip either. The image should appear in the preview window without constantly disappearing.

The buffer uses local recording settings and can increase the load on the CPU, GPU, or RAM. This is especially noticeable if the stream is already being encoded in software while a high-resolution, high-frame-rate recording runs at the same time. Before an important stream, it is best to do a quick test in a separate scene or on a test run.

Also check the recording folder. If there is little space on the disk, the user does not have write permissions, or the path points to a disconnected drive, OBS may fail to save the finished file. If the needed Replay Buffer section is not displayed, open the output settings and try selecting advanced mode. Tab names may differ slightly depending on the OBS version.

How to Enable Replay Buffer in OBS Settings

Open OBS and go to "Settings," then to the "Output" section. Find the Replay Buffer block or tab. In advanced mode, this section is usually displayed separately from the main stream and recording settings.

1. Enable the Enable Replay Buffer option.
2. Set Maximum Replay Time — the maximum length of the saved segment.
3. If needed, set Maximum Memory — the limit on memory the buffer can use.

The maximum time determines how many of the last minutes OBS will keep available for saving. If you set a larger value, you can capture a longer segment, but resource usage will increase. A small buffer is suitable for short gaming moments, while long breakdowns or matches will require increasing the time.

In the recording settings, check the file format, save path, and filename prefix. In most setups, Replay Buffer uses the local recording path, so saved replays should be looked for there. If you change the folder, memorize the new path right away or open it through File Explorer after testing.

How to Choose Time and Memory Limit

The buffer duration depends not only on the value in OBS but also on the video stream size. The higher the resolution, frame rate, and encoding quality, the more data needs to be held. The Maximum Memory limit protects the system from uncontrolled RAM usage, but if the limit is too small, the actual segment may be shorter than the set value.

For a rough estimate, you can use the local recording bitrate. For example, a stream at 10 Mbps creates about 1.25 MB of data per second, not counting additional information. That is roughly 75 MB per minute. The actual size depends on the codec, audio, and nature of the image: a dynamic game usually requires more data than a static scene.

You do not have to choose the longest possible buffer right away. Start with the duration you actually need for a clip and check the load via OBS statistics. If you see dropped frames, encoder overload, freezes, or lag in the game, reduce the duration, resolution, or local recording load. It is best to test changes before starting regular streams.

How to Start the Buffer and Assign a Hotkey

Enabling Replay Buffer in the settings alone is not enough. After starting OBS, open the "Controls" panel and click Start Replay Buffer. After that, OBS will begin accumulating the last frames. You can also start and stop the buffer using a hotkey.

To assign keys, open "Settings" → "Hotkeys." Find the Start/Stop Replay Buffer and Save Replay actions. For saving a clip, set a convenient combination that is easy to press during the game but hard to hit by accident. Do not use a combination already taken by the game, capture software, or a system function.

If your OBS version has an option to automatically start Replay Buffer along with the stream, you can enable it. Then you will not have to press Start Replay Buffer separately each time. However, still check the status before going live: automatic start will not work if the feature is disabled, the hotkey conflicts, or OBS failed to start the encoder.

After starting the buffer, you need to wait until the required interval accumulates. If you press Save Replay right away, the file will contain only the time since the buffer started, not the full set interval. This is especially important after restarting OBS or changing the scene before a stream.

How to Save the Last Minutes of a Stream

When the moment you want has ended, press the assigned Save Replay hotkey or the button of the same name in the "Controls" panel. OBS will take the data from the buffer and create a video file. The buffer itself keeps running, so pressing again will save a different recent segment.

It is best to press the button right after the event, but not during heavy system load. If you use multiple hotkeys, it is useful to choose a separate combination for starting and another for saving. That reduces the chance of accidentally stopping the buffer instead of recording a clip.

The file name and location depend on the local recording settings. To find new clips quickly, set a clear prefix and save them to a separate folder. Do not mix replays with long stream recordings if you plan to look for short videos for editing later.

Saving the same moment again usually creates a new file, but this depends on the naming rules and settings of the specific OBS version. If the program offers to overwrite an existing file, change the prefix or enable automatic addition of a unique part to the name.

File Format and Audio Saving

Replay Buffer follows the local recording settings, so check them in "Output" → "Recording." The MKV format is often chosen to protect against losing the entire recording if OBS or the computer crashes: an unfinished file in this container is more likely to remain usable for processing. For editing or uploading to a platform, you can convert it via "File" → "Remux Recordings" if you need a different container.

Before going live, check which audio tracks are selected for recording. In "Advanced Audio Properties," you can see where the microphone, game sound, music, and other sources are routed. If the needed track is not selected in the local recording settings, it may be missing from the saved Replay.

For a simple check, just save a short segment and open it in a regular player. Make sure you can hear the voice, game sound, and other important sources, and that the video is not out of sync with the audio. If the player plays only one track, this does not always mean the others are missing: some players cannot conveniently switch multi-track recordings.

Why Replay Buffer Does Not Save the File

If the Save Replay button is inactive, first check whether the buffer itself is running. The enabled option in the settings only means the feature is allowed, not that it is actually working. The OBS panel should show that Replay Buffer is running. Also check that you did not accidentally press the stop hotkey.

If the command works but there is no file, open the local recording path and check the free space. Make sure the folder exists, the drive is connected, and OBS can create files in it. During the test, you can choose a simple path to a folder on a local drive without complex permissions.

A short file usually appears for one of three reasons: the buffer was started shortly before saving, a small maximum time is set, or the system lacks the resources to maintain the required amount of data. First look at the file duration, then check the time settings and OBS statistics.

If the clip freezes, drops frames, or comes out with corrupted video, reduce the load on the encoder. Try lowering the resolution or frame rate of the local recording, shortening the buffer length, and selecting a hardware encoder if it is available and works stably on your computer. After each change, save a test segment.

How to Check the Setup Before Going Live

The check takes a few minutes and helps detect problems with hotkeys, audio, and the save folder before the broadcast starts. Launch OBS, enable Replay Buffer, and wait until part of the set time has passed. Then create a noticeable event in the scene: play a short video, say a few words into the microphone, or open a game.

Press Save Replay and wait for the file to appear. Open it and check the beginning, the end, the sync between video and audio, and the presence of the needed sources. If the clip starts too late, this may be a normal result: the buffer was not fully filled. If it ends earlier than expected, check the maximum time and the memory limit.

After checking, delete the test file or move it to a separate folder. Before each stream, it is useful to make sure that OBS starts the buffer automatically or that you have started it manually. This habit reduces the risk of missing an important moment because the feature was not running.

In Short: What to Do Step by Step

1. Open "Settings" → "Output" and enable Replay Buffer.
2. Set the maximum duration and check the memory limit.
3. Check the path, local recording format, and audio tracks.
4. Assign a Save Replay hotkey in the "Hotkeys" section.
5. Start the buffer manually or enable its automatic start along with the stream.
6. After the moment you want, press Save Replay and check the created file.