SR-20HD: What happens when the SD card gets full while recording video?
If the SD card gets full while you’re recording video on the SR-20HD, recording automatically stops. When recording video for extended durations, use a SD card with an appropriately large capacity.
SDXC cards can be used on the SR-20HD. Before you can use a commercially available SD card with the SR-20HD, you must format it as described in “Formatting an SD Card”.