An application using OBS Virtual Camera does not necessarily receive the same composition you expect from a normal recording. The virtual camera has its own output selection. Check that selection before using it for a remote demonstration.

Identify the feed the application should receive

Open the virtual-camera settings using its gear control in the OBS Controls dock. Program follows the normal OBS output. Preview follows the preparation view in Studio Mode, including changes you make there. Scene stays with one selected scene, and Source stays with one selected source.

Choose according to the intended job. For a demonstration that follows your deliberate scene transitions, Program is a natural match. For a receiver that should always see the document camera while you operate other OBS scenes, a fixed Scene or Source may better express the requirement.

Use recognisable harmless labels while testing. For example, put DEMO OUTPUT in the intended scene and PREPARATION in another. Labels make a routing mistake apparent before customer information or unfinished material is present.

Inspect the receiver, not only OBS

Start Virtual Camera in OBS. In the receiving application's local camera settings or preview, choose OBS Virtual Camera. Keep the exercise outside an active meeting or broadcast. Confirm which label actually arrives.

Change the OBS preview, then perform a deliberate program transition. Observe the receiving preview after each action. With a fixed selection, changing the normal program should not redirect the feed to another scene; with Program, the committed transition should be reflected.

If the receiver shows an unexpected view, revisit the output choice before changing unrelated camera permissions or reinstalling software. A functioning but wrongly selected feed is a routing problem.

Check framing and small text inside the receiving preview as well, since that is the view the other application uses. Record the accepted output mode with the session setup notes. Stop Virtual Camera when the rehearsal is finished, and recheck the receiving preview before a later authorised session.

Sources: OBS documentation.