Canon PowerShot V10 Advanced User's Manual page 275

The image flickers or horizontal stripes appear during movie recording.
Flickering, horizontal stripes (noise), or irregular exposures can be caused by
fluorescent lighting, LED lighting, or other light sources during movie recording. Also,
changes in the exposure (brightness) or color tone may be recorded.
I cannot take still photos during movie recording.
Still photos cannot be taken during movie recording. Stop movie recording before
shooting still photos.
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