3GP Video
3GP is the mobile-phone video format 3GPP released in April 2003 — the telecom standards body behind 3G cellular networks, not ISO. Its 4-byte brand code at offset 8 (`3gp4` through `3gp9`) encodes the 3GPP Release that wrote the file. The version number is a cellular-standards Release schedule.
أسئلة شائعة
How do I convert 3GP to MP4?
FileDex converts 3GP to MP4 in your browser — drop the file into the converter above. Newer 3GP files use the same compression as MP4 (H.264 video, AAC audio); FileDex repackages them into MP4 in seconds with no quality loss. Older 3GP files use legacy mobile compression (H.263 video, AMR-NB audio) that MP4 does not accept — for those, FileDex re-compresses the streams into modern formats.
What is a 3GP file?
3GP is a mobile-phone video container the 3rd Generation Partnership Project published in TS 26.244 in April 2003. The byte structure is the same ISO Base Media File Format as MP4 — the difference is a 4-byte brand label at offset 8 that encodes which 3GPP Release authored the file.
What is the difference between 3GP and MP4?
Structurally almost nothing. Both use the same ISO Base Media File Format underneath. The difference is 4 bytes at offset 8: 3GP writes `3gp4`-`3gp9`, MP4 writes `mp42` or `isom`. In practice that means modern 3GP files re-pack into MP4 in seconds with no quality loss; older 3GP files from feature phones need to be re-compressed.
How do I open a 3GP file?
VLC Media Player handles every 3GP variant on Windows, macOS, and Linux. K-Lite Codec Pack adds 3GP support to Windows Media Player Legacy. Modern Windows 11 uses the new Media Player app, which handles 3GP natively. Most modern Android players accept 3GP natively. iOS removed native 3GP support — use FileDex above to produce an MP4.
What is the difference between 3GP and 3G2?
Same byte structure, different cellular ecosystem. 3GP came from 3GPP — the GSM standards body covering Vodafone, Orange, T-Mobile, most of the world. 3G2 came from 3GPP2 — the CDMA2000 standards body covering Verizon, Sprint, KDDI. They share video codecs but split on audio: 3GP uses AMR codecs; 3G2 uses EVRC and QCELP.
ما يميز .3GP
The Only Video File Format Authored by a Telecom Standards Body
Almost every major video container traces to ISO/IEC, a single vendor (Apple's MOV, Microsoft's AVI, Google's WebM), or a multimedia industry consortium. 3GP traces to a cellular-network standards body. The 3rd Generation Partnership Project — 3GPP — founded in December 1998 by seven national telecom standards bodies: ARIB in Japan, ATIS in the United States, CCSA in China, ETSI in Europe, TSDSI in India, TTA in Korea, TTC in Japan. Together they write the specifications for the world's cellular networks. When IANA registered the video/3gpp MIME type in 2004 (RFC 3839), the authors were a Nokia engineer (Roberto Castagno) and an Apple engineer (David Singer) — co-authoring the spec for a format that would outlive most of Nokia's phone business. Five years later, in April 2003, 3GPP published TS 26.244 — a multimedia file format spec for the cellular networks it was already standardizing. The file format inherited its byte structure from ISO/IEC 14496-12 (the ISO Base Media File Format, shared with MP4 and MOV). What was new was the governance lineage: a video container whose spec authors were cellular-network engineers, whose change control flowed through the same working groups writing GSM voice-channel specs and 3G data-link protocols. Which is also why every 3GP file's first bytes carry a timestamp not of when the file was written, but of which Release of cellular standards produced it.
اكتشف التفاصيل التقنية
Read the Brand Code, Read the Cellular Network Year
Every 3GP file carries a 4-byte brand label at offset 8 of the ftyp box. The label encodes a 3GPP Release. 3gp6 means Release 6, frozen March 2005 — the Release that added H.264 video to 3GP. Open a 3GP file recorded on a 2008 BlackBerry: bytes 8 through 11 will read 3gp6. The file's own bytes carry the Release that wrote it. Other brand codes mark earlier and later Releases — 3gp4 for 2001 GSM 2.5G, 3gp5 for 2002, 3gp9 for 2010. MP4RA — the registration authority where every legal MP4 brand is filed, administered by Apple — has 26+ entries for the 3GPP family: Release-numbered codes (3gp4 through 3gp9) plus profile-specific brands (3gs6 for Release 6 streaming server, 3gh9 for Release 9 adaptive streaming, 3gtv for TV over 3GPP, 3gvr/3vra/3vrb/3vrm for VR profiles). A 3GP file's brand code is a forensic timestamp of the cellular-network era it was authored in. The brand says the Release. The codec says the bandwidth — and the bandwidth says what the cellular network could carry in 2003.
When the Codec Defaults Are What the Antenna Could Carry
3GP's mandatory baseline audio codec is AMR-NB — Adaptive Multi-Rate Narrowband. 4.75 to 12.2 kbps at 8 kHz — the bandwidth of a cellular voice call. 3GPP standardized AMR-NB in October 1999, four years before the 3GP file format itself existed. The codec wasn't designed for 3GP. It was designed for GSM voice channels — eight modes that fit GSM full-rate slots, six modes that fit half-rate slots. The same logic shaped video. H.263 — 3GP's original video codec — was an ITU-T spec from 1995 designed for low-bandwidth video calls. At 176×144 pixels, 7.5 frames per second, ~64 kbps, an H.263 + AMR-NB 3GP file's total payload sat at roughly 76 kilobits per second. Why those numbers? Because in 2003, a cellular network's video uplink capacity was capped at about 64 kbps. A 3GP file's defaults aren't a video-quality choice. They're the most that the antenna could carry. That cellular network had two halves. One survived. The other shut down in 2022.
The Format Split That Tracked Carriers — and Outlived One Half
December 31, 2022. Somewhere on Verizon's network operations floor, a switch flipped — the CDMA2000 voice channels went dark. Every phone built for that network, and every .3g2 file ever produced by a Verizon device, became archaeology. 3GP and 3G2 are siblings. Same ISO Base Media File Format underneath. Same MPEG-4 and H.264 video codecs. The split is in the audio: 3GP allows AMR-NB and AMR-WB (the GSM voice codecs); 3G2 allows EVRC, QCELP, and SMV (the CDMA voice codecs, written by Qualcomm for the CDMA2000 networks Verizon and Sprint and KDDI ran). Two file formats from the same byte spec, governed by two parallel cellular-standards bodies — 3GPP for the GSM ecosystem covering most of the world, 3GPP2 for the CDMA2000 ecosystem covering Verizon, Sprint, KDDI, and South Korea. MP4RA tells the story: 26+ registered brand codes for 3GP. One for 3G2 — 3g2a, generic, no Release-numbering. The CDMA carriers shut down their networks. Verizon switched off CDMA on December 31, 2022. Sprint via T-Mobile switched off July 1, 2022. KDDI shut down its CDMA2000 1xRTT service in March 2022. Every .3g2 MMS attachment from a 2008 Verizon Razr or a 2010 KDDI flip phone still carries the GSM-vs-CDMA divergence in its byte structure. 3GP itself isn't dead. Industrial cellular cameras, IoT video uploaders, and some Android low-bandwidth recording modes still write 3gp9-branded files in 2026. The format survived the network it was built for. The cellular network the format was built for is gone. The files persist.
حوّل .3GP إلى...
المرجع التقني
- نوع MIME
video/3gpp- Magic Bytes
00 00 00 xx 66 74 79 70 33 67 70ftyp box with 3gp brand.- المطوّر
- 3rd Generation Partnership Project
- سنة التقديم
- 2003
- معيار مفتوح
- نعم — عرض المواصفات
ftyp box with 3gp brand.
البنية الثنائية
3GP files use the ISO Base Media File Format defined by ISO/IEC 14496-12 — the same byte layout as MP4, MOV, M4V, and HEIF. Every 3GP file is a sequence of `boxes`. Each box begins with a 4-byte size field followed by a 4-byte type tag. The first box is always `ftyp` — the file's first labeled section — at offset 4 (bytes `66 74 79 70` ASCII `ftyp`). The ftyp box payload starts at offset 8 with the major_brand: a 4-byte ASCII string that identifies which kind of MP4 family member this file is. 3GP uses a Release-encoded brand label at offset 8: `3gp4` (33 67 70 34, Release 4 from March 2001), `3gp5` (Release 5, March 2002), `3gp6` (Release 6, March 2005 — the Release that added H.264 to 3GP), `3gp7` (Release 7, March 2008), `3gp8` (Release 8, March 2009), or `3gp9` (Release 9, March 2010). MP4RA also registers profile-specific brands like `3gs6` (Release 6 streaming server profile), `3gh9` (Release 9 adaptive streaming), `3gtv` (TV over 3GPP), and `3gvr/3vra/3vrb/3vrm` (VR profiles) — 26+ brands across the 3GPP family. After the major_brand, a 4-byte minor_version, then a list of compatible_brands — additional 4-byte labels the file claims to also conform to (typically `isom` and `mp41` so non-3GPP-aware parsers can read the file as MP4). After the ftyp box, the standard top-level sequence continues with a `moov` box (the index — sample tables, timing, codec descriptions) and an `mdat` box (the encoded video and audio themselves). Inside the moov box, a `trak` box per stream; inside each trak, a `mdia.minf.stbl.stsd` box that names the codec — `s263` for H.263 video, `samr` for AMR-NB audio, `sawb` for AMR-WB, `avc1` for H.264, `mp4a` for AAC. The `.3g2` sibling format inherits the same box structure but writes `3g2a` (or rare DMB MAF variants) at offset 8 and uses CDMA voice codecs (`sevc` for EVRC, `sqcp` for QCELP, `ssmv` for SMV) at the stsd level instead of the GSM AMR codecs.
| Offset | Length | Field | Example | Description |
|---|---|---|---|---|
0x00 | | size | | Big-endian 4-byte length of the ftyp box, including this size field. Determines where the next box begins. |
0x04 | | type | | ASCII tag identifying this as the file type box — the file's first labeled section, mandatory and always at offset 4 per ISO/IEC 14496-12. |
0x08 | | major_brand | | The 4-byte 3GPP Release-encoded brand label that distinguishes 3GP from MP4. `3gp4` = Release 4 (2001); `3gp6` = Release 6 (2005, H.264 added); `3gp9` = Release 9 (2010). MP4RA registers 26+ brands across the 3GPP family. |
0x0C | | minor_version | | Informational version of the major_brand. Common values written by FFmpeg and mobile-phone encoders include 256, 512, and 768. |
0x10+ | | compatible_brands | | List of additional 4-byte brand labels the file also conforms to. The `isom` and `mp41` entries let non-3GPP-aware parsers treat 3GP as MP4 — they walk this list and dispatch on whichever brand they recognize. |
نقاط الضعف
- Demuxer parsing bugs in older FFmpeg `libavformat/mov.c` (which handles MP4, MOV, M4V, and 3GP): CVE-2020-21041 heap overflow, CVE-2017-9608 out-of-bounds read, CVE-2014-9603 heap overflow. Patched in current FFmpeg.
- Android Stagefright vulnerabilities CVE-2015-1538 and CVE-2015-3864 — heap overflows in Android's MP4 / 3GP parser, exploitable via MMS-delivered 3GP attachment. Triggered code execution before the user opened the message. Patched Android 5.1.1+.
- AMR-NB / AMR-WB decoder bugs in legacy multimedia frameworks (CVE-2013-4988 in libstagefright AMR decoder). Apps decoding AMR audio outside browser sandboxes on unpatched devices remain exposed to crafted 3GP payloads.
الحماية: FileDex processes 3GP files entirely in-browser via FFmpeg WebAssembly. The WASM sandbox confines any demuxer or codec exploit to the browser's isolated memory — no host execution, no DLL loading, no Stagefright-style framework contact. AMR-NB / AMR-WB decoding runs inside the same sandbox.
- مواصفات 3GPP TS 26.244 — Transparent end-to-end Packet switched Streaming Service (PSS); 3GPP file format (3GP)
- مواصفات Information technology — Coding of audio-visual objects — Part 12: ISO Base Media File Format
- سجل MP4 Registration Authority — Brand registry
- مواصفات RFC 3839 — MIME Type Registrations for 3rd Generation Partnership Project (3GPP) Multimedia files
- سجل file(1) magic database — animation rules
- تاريخ 3GP and 3G2 — Wikipedia