Editing 3GP and 3G2 (section)

==Technical details==
{{Update|3GP codec list (see [https://www.etsi.org/deliver/etsi_ts/126200_126299/126244/12.05.00_60/ts_126244v120500p.pdf release 12 of 2016] p.65)|inaccurate=yes|reason=3GP has expanded codec lists while 3G2 has stagnated|date=February 2021}}
[[Image:Relations between ISO MP4 3GPP and 3GPP2 file format.svg|250px|thumb|right|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.<ref name= "3gpp2-vs-3gpp" />]]
The 3GP and 3G2 file formats are both structurally based on the [[ISO base media file format]] defined in ISO/[[International Electrotechnical Commission|IEC]] 14496-12 – [[MPEG-4]] Part 12,<ref name="3gp-spec-mpeg4part12">{{cite web| publisher = ETSI 3GPP | title = 3GPP TS 26.244; Transparent end-to-end packet switched streaming service (PSS); 3GPP file format (3GP) | date = 2008-12-11 | url = http://pda.etsi.org/pda/home.asp?wkr=RTS/TSGS-0426244v800 | format = PDF | page = 9 | access-date = 2009-05-30}} 
</ref><ref name= "mpeg4part12">{{cite web| title =  ISO Base Media File Format white paper – Proposal | date = April 2006 | url = http://www.chiariglione.org/mpeg/technologies/mp04-ff/ | archive-url = https://web.archive.org/web/20080714101745/http://www.chiariglione.org/mpeg/technologies/mp04-ff/ | archive-date = 2008-07-14 | access-date = 2009-12-26 }}</ref><ref name= "mpeg4part12--new">{{cite web| title =  ISO Base Media File Format white paper – Proposal | publisher = Chiariglione | date = October 2009 | url = http://mpeg.chiariglione.org/technologies/mpeg-4/mp04-ff/ | access-date = 2009-12-26 }}</ref> but older versions of the 3GP file format did not use some of its features.<ref name="3gpp2-vs-3gpp">{{cite web|title=3GPP2 C.S0050-B Version 1.0, 3GPP2 File Formats for Multimedia Services |publisher=3GPP2 |date=18 May 2007 |url=http://www.3gpp2.org/Public_html/specs/C.S0050-B_v1.0_070521.pdf |pages=67, 68 |access-date=2009-06-12 |url-status=dead |archive-url=https://web.archive.org/web/20091007071048/http://www.3gpp2.org/Public_html/specs/C.S0050-B_v1.0_070521.pdf |archive-date=7 October 2009 }}</ref> 3GP and 3G2 are container formats similar to [[MPEG-4 Part 14]] (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 phone]]s. 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 <kbd>.3gp</kbd>
* [[3GPP2]] file format was designed for [[CDMA2000|CDMA]]-based phones and may have the filename extension <kbd>.3g2</kbd>

Some cell phones use the .mp4 extension for 3GP video.

===3GP===
The 3GP file format stores video streams as [[MPEG-4 Part 2]], [[H.263]], or [[H.264|MPEG-4 Part 10 (AVC/H.264)]], and audio streams as [[Adaptive Multi-Rate|AMR-NB]], [[AMR-WB]], [[AMR-WB+]], [[Advanced Audio Coding|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).<ref name="mpeg4part12-3gp">{{cite web
  | title = ISO/IEC 14496-12:2008, Information technology -- Coding of audio-visual objects -- Part 12: ISO base media file format
  | publisher = [[International Organization for Standardization]]
  | year = 2008
  | url = http://standards.iso.org/ittf/PubliclyAvailableStandards/c051533_ISO_IEC_14496-12_2008.zip
  | format = PDF
  | page = 95
  | access-date = 2009-05-30 
 }} 
</ref><ref name="mp4ra">{{cite web
 |title       = Registered types – Codecs
 |publisher   = Registration authority for code-points in "MP4 Family" files – mp4ra.org
 |year        = 2008
 |url         = http://www.mp4ra.org/codecs.html
 |access-date  = 2009-05-31
 |archive-url  = https://web.archive.org/web/20090419074514/http://www.mp4ra.org/codecs.html
 |archive-date = 2009-04-19
 |url-status     = dead
}}</ref> 

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.<ref name="3gp-spec-mpeg4part12" />

A 3GP file is always [[Endianness|big-endian]], storing and transferring the most significant bytes first. {{Citation needed|date=September 2017}}

===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]]), [[Selectable Mode Vocoder|SMV]] or [[VMR-WB]], which was specified by 3GPP2 for use in ISO base media file format.<ref name="mp4ra" /> 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.<ref name="3gpp2-vs-3gpp" /> 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.<ref name="3gpp2-vs-3gpp" />