I would address these

I would address these questions to the stock agency. Ask what format they want video to be delivered in — e.g., mp4, mp2, avi, mov, etc., — and what they mean by “low quality in a technical sense.” Are they saying that your composition is lousy and you have poor shot selection, or that your images are shaky and you should be using a tripod? Without answers from the agency to questions such as these, you’re playing in a game whose rules you haven’t been supplied.

Good luck.