3GP is a multimedia container format defined by the Third Generation Partnership Project (3GPP) for use on 3G mobile phones.
3GP is a simplified version of the MPEG-4 Part 14 (MP4) container format, designed to decrease storage and bandwidth requirements in order to accommodate mobile phones. It stores video streams as MPEG-4 Part 2 or H.263 or MPEG-4 Part 10 (AVC/H.264), and audio streams as AMR-NB, AMR-WB, AMR-WB+ or AAC-LC. A 3GP file is always big-endian, storing and transferring the most significant bytes first. It also contains descriptions of image sizes and bitrate. There are two different standards for this format:
3GPP (for GSM Based Phones, may have filename extension .3gp)
3GPP2 (for CDMA Based Phones, may have filename extension .3g2)
Both are based on MPEG-4 and H263 video, and AAC or AMR audio.
You can use mpcstar to open files with this suffix. http://www.mpcstar.com/
