&mirror

Inverts the video so it is the mirror reflection

General Option! (&push, &room, &view, &scene)

Options

Example: &mirror=2

Value	Description
(no value given)	Mirrors all videos via CSS (local preview and all remote)
0	Forces your local preview to be unmirrored; guests/views are unchanged (excluding rear cameras and OBS Virtualcam/NDI)
1	Mirrors all videos via CSS (local preview and all remote).
2	Behaves like &mirror=1 (mirrors everything); does not invert just the local preview.
3	Mirrors everything, including page text/UI, for teleprompter use.

Details

Mirroring does not work if using the browser's native video full-screen button. Use &effects=2 instead for this use case.

Try F11 or the Electron Capture app (right-click → Resize window -> Fullscreen) to hide the browser menu instead.

Alternative method for mirroring and flipping

If you are looking for a form of rotation and flipping that rotates the actual video, rather than relying on CSS to achieve it, you can check out the sender-side &effects options:

• CSS mirroring does not apply when using the browser’s native full-screen button; use &effects=2 instead. F11 or Electron Capture avoids the native controls.

• Right-click “Mirror” on a video toggles the same CSS mirror state; with &mirror=0/2 it may feel reversed because those modes already override the preview.

• Sender-side &effects will transform the actual video:

  • ?effects=-1 flips vertically

  • ?effects=-2 flips + mirrors

  • ?effects=2 mirrors Note: effects can increase CPU/GPU use, especially in background tabs

• &nomirror: Skips the usual device-based auto-mirror on your local preview (rear cameras/OBS/etc.). Your preview starts unmirrored unless you override with &mirror=1/2/3 or right-click “Mirror.” It does not affect guest/output mirroring.

• &mirroroutput: Parses truthy/falsey (0/false/off disables). When enabled it flips the local preview and signals a “mirror guest globally” state to peers/ director (same plumbing as the director “Mirror Video” button). It effectively forces the outgoing/remote view into a mirrored state regardless of the local device heuristics.

Dedicated teleprompter tool that works for most sites

There's a dedicated tool for mirror, flipping, and rotating websites as part of VDO.Ninja as well:

Teleprompter Tool

In case the built-in options to mirror or flip don't work, the teleprompter app might be a good alternative.

Related

Teleprompter Tool&effects&flip