MOV is a MPEG-4 digital video container format used on Apple’s QuickTime Player. It was developed in 1998 by Apple as the proprietary video format for Macintosh. On top of video data, MOV format can also store audio and text data, such as subtitles. It can open easily on both Macs and PCs, although Windows require 3vix codec.
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M4A is a filename extension for AAC container format and is developed by Apple Inc. M4A music is bought on the iTunes Store and does not come with DRM protection. In terms of quality, M4A is better than MP3 because it is lossless but still compressed. This means that it occupies less storage space and doesn’t lose quality over time.
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