The M4V Converter tool from DRmare looks promising as it's a comprehensive solution that can not only convert M4V videos to MP4, MKV, etc. but also unlock the 24-hour limit from the rented M4V movies.

As a smart video converter specially designed for M4V movies and TV shows, DRmare M4V Converter works much faster and easier than its competitors while producing lossless quality in output video files.