M4V is a digital video container format developed by Apple Inc. It is pretty similar to the popular MP4 in terms of structure, but M4V files can sometimes be DRM protected. Today, M4V is the primary video format for iTunes Store videos and can multiplex together multiple audio and video data.
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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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