> ## Documentation Index
> Fetch the complete documentation index at: https://mintlify.com/niri-wm/niri/llms.txt
> Use this file to discover all available pages before exploring further.
# Screencasting
> Record your screen, individual windows, and use advanced screencasting features in niri
## Overview
The primary screencasting interface that niri offers is through **portals and pipewire**. It is supported by:
* [OBS Studio](https://obsproject.com/)
* Firefox
* Chromium
* Electron apps
* Telegram
* Other apps using xdg-desktop-portal
You can screencast both **monitors** and **individual windows**.
### Requirements
You need a working D-Bus session
Install and configure PipeWire
Install `xdg-desktop-portal-gnome`
Run niri as a session through `niri-session` or from a display manager
On widely used distros, this should all "just work".
### Alternative Methods
Alternatively, you can use tools that rely on the `wlr-screencopy` protocol, which niri also supports.
## Blocking Windows from Screencasts
You can block out specific windows from screencasts, replacing them with solid black rectangles. This is useful for password managers, messengers, or any sensitive content.
### Window Rules
Block windows using the `block-out-from` window rule:
```kdl theme={null}
// Block out password managers from screencasts.
window-rule {
match app-id=r#"^org\.keepassxc\.KeePassXC$"#
match app-id=r#"^org\.gnome\.World\.Secrets$"#
block-out-from "screencast"
}
```
### Layer Rules
You can similarly block out layer surfaces:
```kdl theme={null}
// Block out mako notifications from screencasts.
layer-rule {
match namespace="^notifications$"
block-out-from "screencast"
}
```
Check the window rules documentation for more details and examples
## Dynamic Screencast Target
Available since version 25.05
Niri provides a special screencast stream that you can change dynamically. It shows up as **"niri Dynamic Cast Target"** in the screencast window dialog.
### How It Works
When you select it, it will start as an empty, transparent video stream. Then, you can use the following binds to change what it shows:
`set-dynamic-cast-window` - Cast the focused window
`set-dynamic-cast-monitor` - Cast the focused monitor
`clear-dynamic-cast-target` - Go back to empty stream
### Configuration Example
```kdl theme={null}
binds {
Mod+Shift+C { set-dynamic-cast-window; }
Mod+Shift+M { set-dynamic-cast-monitor; }
Mod+Shift+X { clear-dynamic-cast-target; }
}
```
### Command Line Usage
You can also use these actions from the command line, for example to interactively pick which window to cast:
```bash theme={null}
niri msg action set-dynamic-cast-window --id $(niri msg --json pick-window | jq .id)
```
### Behavior Notes
* If the cast target disappears (e.g., the target window closes), the stream goes back to empty
* All dynamic casts share the same target
* New casts start out empty until the next time you change the target (to avoid surprises)
## Indicating Screencasted Windows
Available since version 25.02
The `is-window-cast-target=true` window rule matches windows targeted by an ongoing window screencast. You can use it with a special border color to clearly indicate screencasted windows.
This works for windows targeted by dynamic screencasts, but will **not** work for windows that just happen to be visible in a full-monitor screencast.
### Example Configuration
```kdl theme={null}
// Indicate screencasted windows with red colors.
window-rule {
match is-window-cast-target=true
focus-ring {
active-color "#f38ba8"
inactive-color "#7d0d2d"
}
border {
inactive-color "#7d0d2d"
}
shadow {
color "#7d0d2d70"
}
tab-indicator {
active-color "#f38ba8"
inactive-color "#7d0d2d"
}
}
```
## Windowed (Fake) Fullscreen
Available since version 25.05
When screencasting browser-based presentations like Google Slides, you usually want to hide the browser UI, which requires making the browser fullscreen. This is not always convenient, especially if you have an ultrawide monitor or just want to leave the browser as a smaller window.
The `toggle-windowed-fullscreen` bind helps with this. It tells the app that it went fullscreen, while in reality leaving it as a normal window that you can resize and put wherever you want.
### Configuration
```kdl theme={null}
binds {
Mod+Ctrl+Shift+F { toggle-windowed-fullscreen; }
}
```
Keep in mind that not all apps react to fullscreening, so it may sometimes look as if the bind did nothing.
### Use Case Example
Here's an example showing a windowed-fullscreen Google Slides presentation, along with the presenter view and a meeting app:
## Screen Mirroring
For presentations it can be useful to mirror an output to another. Currently, niri doesn't have built-in output mirroring, but you can use [`wl-mirror`](https://github.com/Ferdi265/wl-mirror) that mirrors an output to a window.
The command below requires [`jq`](https://jqlang.org/download/) to be installed.
### Configuration
```kdl theme={null}
binds {
Mod+P repeat=false { spawn-sh "wl-mirror $(niri msg --json focused-output | jq -r .name)"; }
}
```
### Usage Steps
Focus the output you want to mirror
Press `Mod+P` to start `wl-mirror`
Move the `wl-mirror` window to the target output
Fullscreen the `wl-mirror` window (by default, `Mod+Shift+F`)