(MP4), which is also based on MPEG-4 Part 12. The 3GP and 3G2 file format were designed to decrease storage and bandwidth requirements to accommodate
mobile phones. They are good for lower end smartphones for faster streaming & download. 3GP and 3G2 are similar standards, but with some differences: •
3GPP file format was designed for
GSM-based phones and may have the filename extension •
3GPP2 file format was designed for
CDMA-based phones and may have the filename extension Some cell phones use the extension for 3GP video.
3GP The 3GP file format stores video streams as
MPEG-4 Part 2,
H.263, or
MPEG-4 Part 10 (AVC/H.264), and audio streams as
AMR-NB,
AMR-WB,
AMR-WB+,
AAC-LC,
HE-AAC v1 or Enhanced aacPlus (HE-AAC v2). 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. These extensions were registered by the registration authority for code-points in ISO base media file format ("MP4 Family" files). For the storage of MPEG-4 media specific information in 3GP files, the 3GP specification refers to MP4 and the AVC file format, which are also based on the ISO base media file format. The MP4 and the AVC file format specifications described usage of MPEG-4 content in the ISO base media file format. A 3GP file is always
big-endian, storing and transferring the most significant bytes first.
3G2 The 3G2 file format can store the same video streams and most of the audio streams used in the 2007 3GP file format. 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. The 3G2 specification also defined some enhancements to 3GPP
Timed Text. 3G2 file format does not store Enhanced aacPlus (HE-AAC v2) and AMR-WB+ audio streams. For the storage of MPEG-4 media (AAC audio, MPEG-4 Part 2 video, MPEG-4 Part 10 – H.264/AVC) in 3G2 files, the 3G2 specification refers to the MP4 file format and the AVC file format specification, which described usage of this content in the ISO base media file format. For the storage of H.263 and AMR content 3G2 specification refers to the 3GP file format specification. ==Device support==