Convert 3G2 to CAF — Free Online Tool
Extract and convert the audio track from a 3G2 mobile video file into a CAF (Core Audio Format) file using uncompressed PCM audio. This is especially useful when you need to bring legacy CDMA mobile video audio into Apple's professional audio ecosystem with full fidelity.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your 3G2 file here
or click to browse
Free — no uploads, no signups. Your files never leave your browser.
Settings
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
A 3G2 file typically contains a video stream (encoded with H.264/libx264) and an AAC audio track optimized for low-bitrate CDMA mobile transmission. During this conversion, FFmpeg discards the video stream entirely and extracts only the audio, then re-encodes it from AAC into 16-bit signed little-endian PCM (pcm_s16le) — an uncompressed format — wrapped in Apple's CAF container. The lossy AAC compression from the original 3G2 is decoded and expanded into raw PCM samples, so the output will be significantly larger than the source but is fully compatible with Core Audio-based tools on macOS and iOS. No video data is carried over since CAF is a pure audio container.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg binary. In this browser-based tool, FFmpeg runs entirely via WebAssembly (FFmpeg.wasm) inside your browser with no server upload. When running locally for files over 1GB, this calls your desktop-installed FFmpeg executable. |
-i input.3g2
|
Specifies the input file in 3G2 format — a 3GPP2 multimedia container typically containing an H.264 video stream and an AAC audio track encoded for CDMA mobile transmission. FFmpeg will demux both streams but only the audio will be processed further. |
-c:a pcm_s16le
|
Sets the output audio codec to 16-bit signed little-endian PCM, which is fully uncompressed audio. This decodes the lossy AAC audio from the 3G2 source into raw PCM samples, producing the highest-fidelity representation of what was stored in the mobile video file, compatible with Core Audio and all Apple professional tools. |
-b:a 128k
|
Specifies a target audio bitrate of 128 kbps. For PCM codecs like pcm_s16le, this parameter is effectively overridden by the codec's fixed bit depth and sample rate — uncompressed PCM bitrate is determined by sample rate × bit depth × channels, not a target bitrate. This flag is included for consistency but does not alter the uncompressed output. |
output.caf
|
Defines the output file as a CAF (Core Audio Format) container. FFmpeg infers the CAF format from the .caf extension and wraps the pcm_s16le audio stream inside Apple's CAF structure, which supports large file sizes and is natively readable by macOS, iOS, Logic Pro, GarageBand, and Xcode. |
Common Use Cases
- Recovering audio from old 3G2 video clips recorded on early 2000s CDMA phones (Verizon, Sprint) for archival in a lossless-friendly Apple format
- Importing audio from 3G2 mobile video into Logic Pro, GarageBand, or Final Cut Pro, which natively handle CAF files
- Preparing voice memos or field recordings captured on legacy 3G mobile devices for editing in an Apple audio workflow
- Converting 3G2 ringtone or multimedia content into a high-compatibility audio format for use in Xcode projects or iOS app development
- Extracting dialogue or ambient audio from 3G2 clips for use as samples in a DAW that prefers uncompressed PCM input
- Archiving mobile video soundtracks from CDMA-era devices into an Apple-native format that supports large file sizes and broad codec flexibility
Frequently Asked Questions
No — the original 3G2 audio was encoded in AAC at a low bitrate optimized for CDMA mobile networks, which already introduced lossy compression. Converting to pcm_s16le PCM in CAF decodes that AAC and stores the result as uncompressed audio, so it preserves exactly what was in the AAC stream without further degradation. However, the quality ceiling is set by the original AAC encoding, and the conversion cannot recover detail that was discarded during that initial mobile compression.
3G2 files use AAC audio compression specifically designed for low-bandwidth CDMA transmission, which achieves very small file sizes. CAF with pcm_s16le stores completely uncompressed audio at 16 bits per sample, typically resulting in files 10–20 times larger for the same duration. For example, one minute of mono audio at 44.1 kHz in AAC at 64k is around 480 KB, while the same content as pcm_s16le PCM is about 5.3 MB.
Generally, no. 3G2 files store metadata in 3GPP2-specific atoms that have no direct equivalent in the CAF container format. FFmpeg will not automatically transfer tags like creation time, device model, or GPS coordinates during this conversion. If metadata preservation is important, you should extract and re-embed tags manually using a tool like mp4info before conversion or afinfo after.
Yes. CAF supports multiple codecs including AAC, FLAC, libopus, libvorbis, and various PCM variants. To use FLAC for lossless compression with a smaller file size than PCM, you would change the command to: ffmpeg -i input.3g2 -c:a flac output.caf. To keep AAC (avoiding any re-encoding from the original), use: ffmpeg -i input.3g2 -c:a aac -b:a 128k output.caf.
The pcm_s16le codec is uncompressed, so the -b:a bitrate flag in this command has no practical effect on quality — quality is governed instead by the sample rate. To upsample or explicitly set a sample rate, add -ar 44100 (or 48000) before the output filename: ffmpeg -i input.3g2 -c:a pcm_s16le -ar 44100 output.caf. Note that upsampling cannot recover frequencies lost in the original AAC compression.
On macOS or Linux, you can loop over all 3G2 files in a directory with: for f in *.3g2; do ffmpeg -i "$f" -c:a pcm_s16le -b:a 128k "${f%.3g2}.caf"; done. On Windows Command Prompt, use: for %f in (*.3g2) do ffmpeg -i "%f" -c:a pcm_s16le -b:a 128k "%~nf.caf". This is particularly useful for bulk-archiving old mobile media libraries.
Technical Notes
3G2 (3GPP2) was designed for CDMA networks like those operated by Verizon and Sprint, and its audio tracks are almost universally AAC encoded at low bitrates (often 64k or below) to minimize transmission costs. When FFmpeg decodes this AAC stream for conversion, the full PCM decode is performed, meaning any quantization noise or frequency-limited artifacts from the original mobile encoding will be present in the CAF output. The pcm_s16le codec in CAF provides 16-bit resolution, which is CD quality (65,536 amplitude levels) and is the default for Core Audio workflows on Apple platforms. CAF was specifically designed by Apple to overcome the 4 GB file size limit of AIFF and WAV, making it suitable for long-form audio even at uncompressed bitrates. One known limitation is that CAF files are not broadly playable outside of Apple software and FFmpeg — they are not suitable for web delivery or cross-platform sharing and should be considered a production/archival format. Since 3G2 does not support multiple audio tracks or subtitles, there is no risk of data loss from those features during this extraction.