An important feature for broadcasting of any kind - and a favorite feature of tools like
Nvidia Shadowplay or Elgato’s Game Capture software - is the ability to record something
that just happened, without having been recording the whole time.
While broadcasting you might want to run an instant replay, too!
Whether you call it DVR, Shadow Recording, Flashback recording, or just a good ol’
replay - I’m going to show you how you can do it in OBS Studio, though access to it is
somewhat limited.
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I’m EposVox, here to make tech easier and more fun, and welcome back to my OBS Studio
tutorial course.
I have many, many more videos on the software in the playlist linked in the description.
Check that before asking questions, and check the introduction video to learn how this course
works, if you get confused.
I actually had considered just not including Instant Replay or DVR in this course, because
I don’t consider it a viable option for many - given the restrictions - but it’s
my goal to provide as much information as possible, so here you go.
OBS Studio does have a replay buffer feature, but it requires being in the “Simple”
Output Mode - limiting your options and potentially your performance.
Some people can use the Simple mode just fine, but I’ve had huge issues with it, and can’t
see myself using it much.
Hopefully in the future they will enable replay buffer for custom output settings.
I’m going to show you how to set up the replay buffer for DVR recording first, and
then we’ll get into the more complicated use of utilizing it as an instant replay function
within a broadcast.
BUT you need to know how the normal DVR features work before being able to run instant replays.
In OBS Studio, the feature you want is called the “Replay Buffer.”
It literally buffers some of your video feed into memory to then save later.
This works very similarly to Shadowplay or Elgato’s Game Capture, but instead of saving
to a temporary file on disk and copying over, it stores it in your actual system memory,
or RAM.
Low RAM machines will be unable to use this feature due to this.
Open your settings and go to Output.
Again, switch to “Simple” mode if you haven’t already - you might want to duplicate
your profile and use the new copy to mess with this.
Set your normal encoding settings in the Simple Output mode, and then at the bottom, check
“Enable Replay Buffer.”
Here you can set how long the buffer should store, and what your final DVR recording length
will be.
I do NOT recommend setting this for long - this records straight to your system memory, so
unless you have a crapload of RAM installed on your machine or are recording to a super
low bitrate, you don’t have a lot of room to work with.
As you change your time, in seconds, it gives you a rough estimate of the file size and
subsequent memory usage.
So if your recording Quality is set to “High Quality, Medium File Size”, 20 seconds of
replay time consumes 512 megabytes.
So at all times while OBS is running and the replay buffer is active, 512 megabytes of
RAM are being consumed just for this process.
Take a look at your system memory, keep in mind the required RAM availability for your
other programs or games running, and choose wisely.
If you have it use up all of your system memory, OBS could crash, your game could crash, or
your whole system could halt.
You don’t want that.
Hit Apply to change your settings.
Your replay recordings will go to the same recording path as normal recordings, also
set in this menu.
By default it uses the same naming scheme as normal recordings, but with a “Replay”
suffix.
You can go to “Advanced” Settings and customize the filename prefix or suffix for
the replay so you know which file is which.
Once you’ve applied your settings and are ready to go, you need to make sure you don’t
forget one very important thing!
Enabling the replay buffer adds a new button next to your Start Recording and Start Streaming
buttons to start the replay buffer.
This helps make sure that it’s only eating up your RAM when you need it BUT that also
makes it quite a bit easier to forget entirely and then you can’t actually use your replay
buffer at all.
Plus, you have to actually set a hotkey to save the replay buffer to a file, or it won’t
let you start the buffer in the first place.
Open your settings again, go to Hotkeys, and now there’s a “Replay Buffer” section.
For whatever reason, only the “Save Replay Buffer” hotkey is here, the “Start”
and “Stop Replay Buffer” hotkeys are in the section above, but oh well.
If you can be 100% absolutely certain that you will click “Start Replay Buffer” when
you start recording, then you don’t need to set a hotkey for it, but otherwise (if
you plan on relying on the replay feature a lot) I recommend setting the “Start”
and “Stop Replay Buffer” hotkey to be the same hotkeys as your “Start” and “Stop
Recording” hotkeys, so that it’s always going at the same time and you never forget
it.
Then set a hotkey for “Save Replay Buffer” - this is the equivalent of hitting ALT-F10
(by default) in Nvidia shadowplay to save the last minute or so of footage to disk.
Then whenever something happens that you wish to capture, you can just hit that hotkey real
fast and know it’s saved and ready to go.
Just remember it will take a few seconds to dump your buffer from memory to disk and get
footage recording to the buffer again, so don’t smash it back to back a bunch - you
might wind up with messed up files.
~3 seconds is usually enough, depending on your target recording drive and how long your
buffer is.
That’s all you need to get started using OBS Studio’s replay buffer to save clips
after the fact.
I mentioned before how Simple Output Mode might not be preferable for most uses.
Unless you’re specifically wanting to use this feature during normal recording or streaming
sessions, I actually recommend utilizing a separate profile for this.
For the people who just want to have it open to capture footage after the fact such as
what many of us do with Shadowplay, a separate profile works.
Duplicate your primary recording profile, name the new one something like “DVR recording”
and set it to Simple Mode and set up the replay buffer.
Then just have it open with the Replay Buffer going while you game and hit your hotkey whenever
you need to save a cool moment.
Alright, so what about an actual instant replay?
Actually calling up a quick moment to your live stream?
This part is going to sound really complicated, but I promise it’s easy.
There’s a couple things you need to pay close attention to, and you’ll need 3 hotkeys,
but it’s worth it for the production value.
First and foremost, for this to work at all, you will need to go to Advanced Settings in
OBS and click the checkbox for “Overwrite if file exists” under Recording settings.
Unfortunately as of the time of making this guide, this setting applies to all recording
in general, not just Replay.
So you will need to manually move, transfer, copy, save, whatever your primary recordings
every time you start and stop recording or they will get overwritten.
Annoying, but it’s what you have to deal with for now.
Then change the name formatting so it doesn’t have those time-based variables to change.
Just give it a static name.
The reason you have to enable that is actually the convenient part of how Instant Replay
will work at the same time.
You see, OBS Studio reads information from files without abstracting the files to memory
or modifying them.
This is how you can use .txt text files to create labels for the currently-playing song
and so on.
A separate program just updates the text file and OBS simply displays whatever the file
says at any given time.
Similarly, if you remove an image file used in a scene in OBS, it will disappear from
the scene.
So we use this capability to create a replay scene.
Make a new Scene, call it something like “Instant Replay.”
Here we will add a video source, but not just yet..
First, you need to go on and run the replay buffer and save a replay file first so that
you can reference it.
So start the buffer, give it a couple seconds, trigger your “Save Replay” hotkey, and
then stop the buffer.
Now add a video source and point OBS to this video file.
Now, whenever you call up this scene, it will load the most recent replay file - assuming
you give it the few seconds needed to dump the file to disk.
Sweet.
We’ll set that up in just a second.
I do want to note that it might be a good idea to make and use some sort of graphical
overlay to indicate that this is a replay.
I’ve made a super basic one and linked it in the video description, as an example.
Simply add it as an image source to this scene so it’s clear what’s happening.
Next, you might want to create some sort of stinger transition to happen in-between your
normal scene and your replay scene.
This should be 3 to 5 seconds long to allow your computer enough time to fully save your
replay buffer to disk and finalize the file before OBS tries to pull it up, or else the
replay won’t play properly.
This can be an image if you really can’t make a video clip, or I’ve created a generic
one and linked it in the video description.
Down there I’ve also linked a video by Jeff, or Steggy, from Elgato Gaming - who has made
an Elgato-themed transition clip, too.
Check that out if you have the time.
Instead of using OBS’s new Stinger Transition feature that I covered in the Transitions
section - since you can’t currently assign per-scene transitions and you don’t want
to show an “INSTANT REPLAY” based transition for every scene switch, it’s best to have
this be it’s own scene.
Add your transition clip as a video source and you’re good to go.
Next, you need to tackle hotkeys.
Like I said earlier, it’s easier to have “Start” and “Stop Replay Buffer” matched
to your “Start” and “Stop Recording” or “Streaming” buttons so you don’t
forget to hit it, but you do need to assign a hotkey that you will remember to the “Save
Replay Buffer” action.
You also need to assign hotkeys to switch scenes over to your transition scene and your
replay scene - and probably back to your main gameplay scene.
Set those and hit Apply.
Now you have a hotkey you can hit to save a replay, and then you can hit the transition
scene hotkey when you’re ready to show off the replay and once the transition reaches
completion, hit the replay scene hotkey.
Let it play out, and switch back to your main scene.
But that’s three hotkeys!
You need good memory or to use some sort of macro keys to best utilize these.
Macro keys on a gaming keyboard with a custom streaming profile could work, or you could
use a macro keypad like the Elgato Stream Deck to make this even easier on you.
With the Stream Deck, you only need to manually map a hotkey for the “Save Replay” command,
and then you can assign scene switching to buttons directly in the Stream Deck software.
Nifty!
Then, while broadcasting, it’s just a couple simple hotkey presses to save a replay, transition,
and call it up.
Like I said before - it sounds super complicated, but it’s a fairly easy concept by time you’re
done.
If you plan on only ever immediately pulling up your replay right after saving it, you
could automate all three of these hotkeys into one with an AutoHotKey script like this
to save the replay, wait, switch to Transition scene, wait, switch to replay scene, wait,
switch back to gameplay scene -- but that leaves you little flexibility while you broadcast.
So that’s it!
Replay buffers, DVR recording, and instant replays in OBS Studio.
Again, two feature requests I have here are to allow use of the replay buffer with Advanced
Output Mode, and to allow per-scene transition assignments.
This seems like a fairly simple feature when you consider how easy it is to set up in Elgato’s
software or Nvidia Shadowplay, but OBS Studio’s implementation is a bit involved.
Hopefully this guide has provided the info you need to get started and replay to your
hearts content.
I hope this episode of my OBS Studio tutorial course has been helpful for you.
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If you like game streaming, come follow me on Twitch and drop a message in chat.
Until next time, I’m EposVox, Happy Streaming!
Thanks for watching this episode of my OBS Studio tutorial course.
More videos like this and a full master class are linked in the playlist in the video description.
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