An earlier post had discussed this but an answer was never really reached:
I am shooting in good light, and I have the IMG QUALITY set for SUPER FINE. I am getting some noise in the blacks, and I'm wondering if switching to FINE will result in a huge change in the quality, or if it will be a slight change and get rid of the dreaded noise in the black areas.
The setting you refer to has nothing to do with video. That setting is for the stills function saved to the SD card. Possibly you're getting noise because either you have AGC on, or have your manual gain setting at anything other than 0dB or -3dB.
For super fine mode, I believe that its best to use that mode for shooting stills. I'd be curious to see what others also have to say about your question, since I love the Canon XH A1 and its resolution dynamics.