Set up OBS for Casttit
Casttit gives OBS a clean window with just your game: no buttons, no borders. You add it once, as a Window Capture with its sound.
No OBS yet, or an older one? Get the newest from obsproject.com: it's free, and Casttit needs 30.1 or newer for the sound.
1. Open the preview in Casttit
Press Open OBS preview in Casttit. A window called Casttit Preview opens with only your game in it. From then on, Casttit opens it by itself whenever your phone goes live. Close it with its button in Casttit if you don't want that.
2. Add it to OBS (once)
- In OBS, under Sources, press + and choose Window Capture.
- For Window, choose [Casttit.exe]: Casttit Preview.
- Set Window Match Priority to Window title must match. Then OBS never picks up Casttit's main window by mistake.
- Turn Capture Audio on. OBS then records Casttit's game sound, whichever headset it plays on. (Capture Audio needs OBS 30.1 or newer. On OBS 28 to 30.0, update OBS, or add an Application Audio Capture (BETA) source for [Casttit.exe] instead.)
- Turn Capture Cursor off, so your mouse doesn't show on stream.
- In the Audio Mixer, mute Desktop Audio. Otherwise the game sound can be missing, or play twice.
3. Keep the preview open
The preview can sit behind other windows, but OBS can't capture a minimised window. If the picture in OBS freezes when you minimise things, that's why.
Keep it at least as big as your stream. OBS records the preview at the window's own size, so for a 1080p stream it should be about 1920 pixels wide: drag its corner out, or double-click its title bar to fill the screen. Then, in OBS, right-click the source and choose Transform → Fit to screen. A small window stretched up by OBS looks soft.
Portrait games
A phone held upright fills only a narrow strip of a 16:9 stream. For portrait games, crop the Window Capture (Alt + drag its edges) and place it beside a facecam or a background, or use a vertical canvas if you stream to Shorts or Reels.
Sound and picture out of step? Casttit's Sync slider lines them up. See Sound and sync.
Questions
Why does OBS record no game sound?
OBS's Desktop Audio records only the Windows default device. If Casttit plays on another headset, Desktop Audio stays silent. Turn on Capture Audio in the Window Capture of Casttit Preview, and OBS records Casttit's sound wherever it plays.
Why does OBS show Casttit's buttons instead of the game?
The Window Capture is pointing at the main Casttit window. Choose '[Casttit.exe]: Casttit Preview' in its properties and set Window Match Priority to 'Window title must match'.
Do I need an OBS plugin?
No. A Window Capture with Capture Audio is all it takes.