blackmagic trouble

I would like to know how to change the *SceneViewport to 8 bit *as well! The Unreal “Media Capture” can only output the same rgba as the viewport but the possible pixel formats in the Media Capture can only set to and 8bit RGBA or Float RGBA. Both not working ith the 10bit Sceneview! Other problem but the same question: Sceneviewport to 8bit: How?