The .3g2 file extension stands for 3GPP2 Multimedia File, which is a multimedia container format developed by the 3rd Generation Partnership Project 2 (3GPP2). This format is primarily used for storing video and audio data on 3G mobile phones, particularly those utilizing CDMA2000 technology (like those common in North America and parts of Asia). It is closely related to the more common .3gp format, but .3g2 is specifically tailored to the standards defined by 3GPP2. The container format is based on the ISO Base Media File Format (ISO/IEC 14496-12), which is also the foundation for formats like MP4. 3G2 files typically contain compressed video streams (often using MPEG-4 Part 2 or H.263) and audio streams (often using AAC or AMR). Due to their origin in mobile telephony, these files are often optimized for low bandwidth and limited processing power, resulting in relatively small file sizes and lower resolutions compared to modern video standards. While less common today with the prevalence of smartphones supporting MP4, 3G2 files were crucial for early mobile video sharing and streaming.