m4a was used strictly to label only audio tracks. It was used as a means to distinguish between video and audio files so. mp4 files theoretically could contain both video and audio within it, it makes it very difficult to determine which files are only video, or only audio, or both. The default file extension for MP4 is '.mp4'. Since the format and contents of the file varies, so does the file extensions: MP4 doesn’t have a specific file extension. Due to ease of transfer and sharing, the MP4 format can be easily distributed illegally.Virtually compatible with all kinds of devices and applications.Versatile with tons of metadata in a single file like object and scene descriptors.Easy to transfer and move around due to significant compression of the file.Useful for online streaming and sharing.Over the years, MP4 has gained popularity due to its efficiency when compressed and portability when shared and streamed online. This makes MP4 a much more versatile file format as opposed to something like MP3. It can carry video, audio, subtitle, and other metadata within a single file. MP4 stands for MPEG-4 which comes from Apple’s QuickTime MOV format and can store more than audio. MP4 is essentially a container format that stores the data of a file, instead of the code.
