3G2 is an audio and video format developed by Third Generation Partnership Project for CDMA-based (Code Division Multiple Access) phones. Actually it is an updated version of the 3GP file extension. Both formats are based on the ISO base media file format that facilitates presentation and interchange of the media. The 3G2 format is flexible and requires little storage space that is why it is mostly used by cell phones for saving files. However 3G2 movies can be played on computers but in some cases additional applications may be needed.

This format was originally intended for voice compression and is able to change the bit rates of encoded audio data. AMR is actively used for encoding and decoding voice while its being transmitted over network channels. The format allows one to consider network capacity and adapt it to channel loads. Due to this, the voice quality is practically undiminished.