Replay buffering

I initially tried setting up replay buffering, but I couldn’t for the life of me get it to work, which made me feel like an idiot.

Once you get it set up, replay buffering is one of the best features to any streamer or recorder; I no longer have to record hours of video in the hopes of some interesting moments. What I do is I start my replay buffer, which writes to my RAM, not HDD, to store the last 180 seconds. If anything interesting happens, I use my hotkey to save the replay (Alt+F9), and I now have an 180-second file. This is very similar to how Twitch Clips work, only you don’t have to yell “SOMEONE CLIP THAT!” to your audience.

Now you should never be able to miss a great moment.

Setting it up

The setting is under Output, but it is only available if you set your Output Mode to Simple; if you use Advanced, replay buffering is no available.

Update October 17, 2017: As of 20.1, Advanced mode supports replay buffering, too.

Change your Output Mode (and remember your previous OBS settings, since OBS will forget them).

Tick Enable Advanced Encoder Settings so you can set your Encoder Preset to Quality as well.

You need to set these things up for replay buffering to work:

  1. Recording path
  2. Maximum replay time (buffer)
  3. Hotkeys for
    • Starting a replay
    • Ending a replay
    • Saving a replay

By default, replay files are prepended with the string “Replay”—and a space afterwards—but you can change what and whether you want to pre- or append any thing under the Advanced settings.

You should now have a “Start Replay Buffer” button on your OBS dash. Click the button to see if you get any errors.

If you don’t, start your replay buffer, and keep OBS running in the background so you can capture any moments.

With replay buffering set up, you may also reconsider turning off the setting Automatically record when streaming and Automatically start replay buffer when streaming on under General. You’ve got your entire session on Twitch, if you’re streaming, and unless it’s something worth saving in full, combining streaming with replay buffering could be preferable. If you’re only recording replays and use .flv, consider using .mp4 or .mkv instead, as they support multitrack audio.

A reason to keep the full recordings of your stream is that your VODs might get muted in the sections where you play copyrighted music.


If you want a video tutorial, I recommend this one—but keep in mind it’s slightly outdated by the time you’re reading this:

Performance hit

Like recordings, your replay buffer probably uses output duplication and should not involve separate encoding; it’s just a bitstream that’s stored in memory (RAM) just like recordings are written to storage (HDD).

If you’re only running replay buffering without recording or streaming, your CPU or GPU, whichever is doing the encoding, will obviously still be under load, so remember to turn it off when you’re not planning on using it.

What next?

If you’re ready for next step, go to the guide for alerts, donations, and notifications.