3GP and 3G2

It is very similar to the 3GP file format but consumes less space & bandwidth, and has some extensions and limitations in comparison to 3GP.

The 3GP and 3G2 file format were designed to decrease storage and bandwidth requirements to accommodate mobile phones.

3GPP allowed use of AMR and H.263 codecs in the ISO base media file format (MPEG-4 Part 12), because 3GPP specified the usage of the Sample Entry and template fields in the ISO base media file format as well as defining new boxes to which codecs refer.

In addition, 3G2 stores audio streams as EVRC, EVRC-B, EVRC-WB, 13K (QCELP), SMV or VMR-WB, which was specified by 3GPP2 for use in ISO base media file format.

[16] Media tags can be read and written on Linux, macOS and Windows using the open source AtomicParsley command-line utility.

Relations between ISO Base Media File Format, MP4 File Format, 3GPP file format and 3GPP2 file format. Based on the 3GPP2 technical specification published on 18 May 2007. [ 7 ]