This is a 1080p, standard-quality video file. It is generated instantly so you can see what you captured, share it quickly, or check the framing without waiting for cloud processing.
It is a generic filename often used by artists or creators for a video cover of a song (e.g., "Misty Cover.mp4"). Cover.mp4
When you record a video with enabled on a compatible Google Pixel device, your phone doesn't just create one file. Instead, it creates a "dual-file" system to balance immediate usability with high-end processing: This is a 1080p, standard-quality video file
Once the boosted version is ready, Google Photos downloads the final high-quality version and typically deletes the massive raw MAIN.mp4 to save space. This is a 1080p