3G2 is a digital multimedia container format developed by the Third Generation Partnership Project (3GPP). It can save both video and audio tracks, just like its sister format, 3GP. However, it’s the updated version of the former because it is designed for CDMA (Code Division Multiple Access) mobile phones, whereas 3GP is intended for GSM phones.
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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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