Convert 3G2 to AVI — Free Online Tool
Convert 3G2 files from legacy CDMA mobile devices into AVI format using H.264 video and MP3 audio. This tool re-encodes the 3G2's AAC audio stream to MP3 (libmp3lame) while preserving the H.264 video, producing an AVI container widely supported by older Windows software and media players.
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FFmpeg Command
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Note: Browser-based encoding uses approximate quality targets. For precise CRF compression, copy the FFmpeg command above and run it on your desktop.
Estimated output:
Conversion Complete!
DownloadHow It Works
3G2 is a container designed for CDMA mobile networks (used by carriers like Verizon and Sprint), typically holding H.264 video and AAC audio at low bitrates optimized for small screens and constrained bandwidth. During this conversion, the H.264 video stream is re-encoded using libx264 with a CRF of 23, and the AAC audio is transcoded to MP3 at 128k using the LAME encoder — because AVI's default audio codec in this tool is libmp3lame, not AAC. The output is wrapped in Microsoft's AVI container, which uses interleaved audio/video chunks rather than the MP4-style atom structure used by 3G2. The special '+faststart' flag used in 3G2 is not needed for AVI, so it is dropped.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary — the same engine running in your browser via WebAssembly. The command shown is fully portable and can be run on any desktop with FFmpeg installed to process files larger than 1GB. |
-i input.3g2
|
Specifies the input file in 3G2 format — a CDMA mobile multimedia container developed for 3GPP2 standards, typically holding low-bitrate H.264 video and AAC audio recorded on mobile devices. |
-c:v libx264
|
Re-encodes the video stream using the libx264 H.264 encoder. Although 3G2 often already contains H.264 video, the stream must be re-encoded because the container format, bitrate, and encoding parameters are changing for the AVI output. |
-c:a libmp3lame
|
Transcodes the audio from the 3G2's native AAC stream to MP3 using the LAME encoder. MP3 is the most broadly compatible audio codec for AVI files, ensuring playback in legacy Windows applications and media players that may not handle AAC inside AVI. |
-crf 23
|
Sets the Constant Rate Factor for the H.264 video encode to 23, FFmpeg's default quality level. For source footage from a 3G2 file that was already compressed at a low mobile bitrate, CRF 23 provides a reasonable quality-to-size balance; lower values like 18 will preserve more detail from the already-compressed source. |
-b:a 128k
|
Sets the MP3 audio bitrate to 128 kilobits per second. Since the source AAC audio in a 3G2 file is often encoded at 64k or lower for mobile transmission, 128k MP3 is a step up in audio quality for the AVI output while keeping file size reasonable. |
output.avi
|
Defines the output file as an AVI container. FFmpeg infers the container format from the '.avi' extension, wrapping the newly encoded H.264 video and MP3 audio into Microsoft's Audio Video Interleave format with interleaved A/V chunks. |
Common Use Cases
- Opening old video clips recorded on a CDMA flip phone or early Android device in legacy Windows video editors like Windows Movie Maker or VirtualDub that don't support 3G2 containers.
- Archiving mobile video footage from early 2000s and 2010s CDMA phones into AVI, a format that remains readable by a wide range of media players on Windows systems without additional codecs.
- Preparing 3G2 clips for import into older video production workflows or industrial systems that specifically require AVI input and cannot handle modern mobile container formats.
- Converting family or personal videos captured on Verizon or Sprint-era phones into a format compatible with DVD authoring tools that accept AVI but reject 3G2.
- Batch-converting a collection of 3G2 clips from an old mobile backup so they can be played or edited on a PC without installing 3G2 codec packs or container splitters.
Frequently Asked Questions
Yes, some quality loss occurs because both the video and audio streams are re-encoded rather than copied. The H.264 video is re-encoded at CRF 23, which is a visually near-lossless setting for most content, but since 3G2 files are already compressed at low mobile bitrates, you are re-encoding already-lossy data. The AAC audio is also transcoded to MP3 at 128k, which is another lossy transcode. For archival purposes, lowering the CRF value (e.g., to 18) will preserve more detail from the source.
3G2 files use AAC as the default audio codec, but AVI's historically dominant and most compatible audio codec is MP3 (via the LAME encoder). While AVI technically supports AAC, broad compatibility with older Windows software and players — which is the main reason to use AVI — is best achieved with MP3 audio. This tool therefore transcodes the AAC stream to MP3 at 128k to maximize playback compatibility with the AVI output.
3G2 files are engineered for CDMA mobile transmission and use aggressive compression at very low bitrates, often resulting in tiny file sizes. AVI with H.264 at CRF 23 is encoded at a higher quality target, which typically produces a larger file. Additionally, the AVI container itself has more overhead than the streamlined 3G2 MP4-style box structure. If file size is a concern, you can increase the CRF value (e.g., to 28 or 35) in the FFmpeg command to reduce the output bitrate.
For typical 3G2 files from mobile devices, AVI handles the core content well since 3G2 files generally contain a single video track and a single audio track without subtitles or chapters — and AVI supports those basics. However, 3G2's '+faststart' metadata flag (for progressive streaming) has no equivalent in AVI. Any GPS or device-specific metadata atoms stored in the 3G2 container will be lost, as AVI does not support that kind of embedded metadata.
Adjust the '-crf' value in the command to control video quality. The scale runs from 0 (lossless) to 51 (worst quality), with 23 as the default. For example, change '-crf 23' to '-crf 18' for higher quality at a larger file size, or to '-crf 28' for a smaller file with slightly more compression. You can also change the audio bitrate by modifying '-b:a 128k' to '-b:a 192k' or '-b:a 256k' for better audio fidelity from the transcoded MP3 stream.
Yes. On Linux or macOS, you can run a simple shell loop: 'for f in *.3g2; do ffmpeg -i "$f" -c:v libx264 -c:a libmp3lame -crf 23 -b:a 128k "${f%.3g2}.avi"; done'. On Windows Command Prompt, use: 'for %f in (*.3g2) do ffmpeg -i "%f" -c:v libx264 -c:a libmp3lame -crf 23 -b:a 128k "%~nf.avi"'. This is particularly useful for bulk-converting an archive of old mobile phone footage.
Technical Notes
3G2 uses an MP4-derived container structure (it shares roots with the MPEG-4 Part 12 file format family) but is specifically profiled for 3GPP2/CDMA2000 devices, meaning the video is often encoded at sub-QVGA or QVGA resolutions with low frame rates and very conservative bitrates. When re-encoding to AVI with libx264 at CRF 23, FFmpeg will preserve the original resolution and frame rate unless you explicitly scale or filter the stream, which means the output AVI may retain the small resolution of the source mobile clip. AVI does not support B-frames in all players when used with older software, but libx264's default settings are generally AVI-compatible. Notably, AVI supports multiple audio tracks in its container specification, which 3G2 does not, though this conversion outputs a single audio track. The '+faststart' flag present in 3G2 encoding (which repositions the MOOV atom for streaming) is irrelevant to AVI, which uses a fundamentally different index-based structure (AVI index chunk, or OpenDML index for larger files). Any 3GPP2-specific metadata such as asset information boxes or location data will not be carried into the AVI output.