Convert 3G2 to DVR — Free Online Tool
Convert 3G2 files — the compact CDMA-era mobile video format — into DVR format for archival or surveillance system compatibility. This tool re-encodes your 3G2 video using H.264 (libx264) and AAC audio, transforming low-bitrate mobile content into a DVR-ready file directly in your browser.
to
FFmpeg Command
Copy this command to run the same conversion locally with FFmpeg on your desktop. Download FFmpeg
Drop your 3G2 file here
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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
3G2 is a container built on the MPEG-4 Part 12 specification, typically carrying H.264 video and AAC audio optimized for CDMA mobile transmission at very low bitrates. DVR is a proprietary recording format used by digital video recorders and surveillance systems, also commonly built around H.264 and AAC but without the mobile-streaming optimizations like the faststart moov atom placement that 3G2 files often use. During this conversion, FFmpeg re-encodes the video stream using libx264 at CRF 23 (a visually balanced quality level) and transcodes the audio to AAC at 128k bitrate. Because both formats share the same underlying codecs, the re-encoding is codec-compatible but not a lossless remux — the file is decoded and re-encoded, meaning some generation loss occurs. The DVR output drops the 3G2-specific mobile streaming flags and produces a plain H.264/AAC stream suitable for DVR playback or ingestion.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg command-line tool, which is running here as FFmpeg.wasm compiled to WebAssembly and executing entirely within your browser — no server upload is involved. |
-i input.3g2
|
Specifies the input file in 3G2 format — the CDMA mobile container that FFmpeg will demux to extract the H.264 video and AAC audio streams for re-encoding. |
-c:v libx264
|
Sets the video encoder to libx264, re-encoding the source H.264 stream from the 3G2 container into a fresh H.264 stream suitable for the DVR output format. |
-c:a aac
|
Sets the audio encoder to AAC, transcoding the source mobile AAC audio (often encoded at very low bitrates for CDMA transmission) into a new AAC stream at the specified 128k bitrate for DVR storage. |
-crf 23
|
Sets the Constant Rate Factor to 23, which is libx264's default quality level — a balanced setting that preserves the visual quality of the 3G2 source without unnecessarily inflating the DVR output file size. |
-b:a 128k
|
Sets the audio bitrate to 128 kilobits per second for the AAC output stream, which is a standard quality level for DVR recordings and significantly higher than the compressed audio bitrates typical in 3G2 CDMA mobile files. |
output.dvr
|
Specifies the output filename with the .dvr extension, signaling FFmpeg to produce a DVR-format container carrying the re-encoded H.264 video and AAC audio streams without the mobile-streaming flags present in the original 3G2 file. |
Common Use Cases
- Archiving old mobile phone recordings from CDMA-era devices (e.g., early Verizon or Sprint smartphones) into a DVR-compatible format for long-term storage on a digital video recorder
- Ingesting surveillance footage originally captured on a mobile device into a DVR system that only accepts its native DVR format
- Converting 3G2 clips recorded on legacy CDMA handsets into a format that a broadcast capture or security review workstation can natively open
- Preparing mobile-captured video evidence for review on DVR playback hardware used in security or law enforcement contexts
- Migrating a library of old 3G2 videos from a CDMA carrier backup to a DVR archive system before decommissioning legacy mobile hardware
- Re-encoding low-bitrate 3G2 footage at a higher quality level (by adjusting CRF) before storing it as a DVR file to improve visual fidelity for review
Frequently Asked Questions
No — 3G2 files from CDMA mobile devices are typically encoded at very low bitrates optimized for cellular transmission, and that original quality cannot be recovered during conversion. Re-encoding with CRF 23 in libx264 will preserve the existing visual information faithfully, but it cannot reconstruct detail lost during the original mobile compression. If anything, re-encoding introduces a small additional generation of lossy compression. To maximize quality, you can lower the CRF value (e.g., to 18) in the FFmpeg command, which increases output file size while preserving more detail from the source.
The 3G2 format uses a '-movflags +faststart' flag during encoding to place the moov atom at the beginning of the file, which is essential for progressive streaming over CDMA mobile networks. DVR format is designed for local recording and playback on dedicated hardware, not network streaming, so this optimization is unnecessary and is dropped during conversion. The resulting DVR file will have its moov atom in the standard position, which is perfectly suited for DVR playback systems but would not be ideal for web streaming.
Both 3G2 and DVR support AAC audio as a default codec, so the audio stream is transcoded from the source AAC (often encoded at a very low bitrate for mobile) to a fresh AAC stream at 128k bitrate. This is not a lossless copy — the audio is decoded and re-encoded, which introduces a small amount of additional lossy compression. If your source 3G2 file's audio was originally encoded below 128k (common for CDMA mobile video), the output at 128k will not actually be higher quality, just a larger bitrate representation of the same degraded audio.
DVR is a proprietary format and different manufacturers (e.g., Hikvision, Dahua, older TiVo systems) implement it with varying internal structures and codec profiles. This tool produces a DVR-extension file with standard H.264/AAC streams, which may be compatible with some systems but not universally recognized by all DVR hardware or software. You should verify the specific codec profile and container requirements of your target DVR system before relying on this conversion for professional security or broadcast workflows.
The quality is controlled by the '-crf 23' flag in the command. CRF stands for Constant Rate Factor, and it works on a scale where lower numbers produce higher quality and larger file sizes, while higher numbers reduce quality and file size. For 3G2 source footage — which is already low-resolution and low-bitrate — a CRF of 18 is a reasonable maximum quality setting, while a CRF of 28 can reduce file size further with modest quality reduction. Changing this value lets you balance the tradeoff between DVR storage space and visual fidelity.
Yes — the displayed command can be adapted for batch processing on your desktop. On Linux or macOS, you can run: 'for f in *.3g2; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.3g2}.dvr"; done' to process all 3G2 files in a directory. On Windows, a similar loop can be written in PowerShell. This is particularly useful for migrating an entire library of CDMA-era mobile recordings, and the browser tool's 1GB file limit makes desktop FFmpeg the better option for large batches.
Technical Notes
3G2 is structurally close to MP4/MOV as it derives from the MPEG-4 Part 12 base format, but it carries specific metadata and structural conventions for 3GPP2 CDMA networks, including the faststart moov atom placement and often very constrained video profiles (e.g., H.264 Baseline Profile at low resolutions like 176x144 or 320x240). When converting to DVR, these mobile-specific constraints are shed and the output is a plain H.264/AAC stream. The re-encoding at CRF 23 uses libx264's default settings, which apply the Main Profile by default — a step up from the Baseline Profile typical in 3G2, though this makes no practical difference if the source resolution is already low. Metadata such as GPS tags, device information, or creation timestamps embedded in the 3G2 container are not guaranteed to be carried over into the DVR output, as the DVR format does not have a standardized metadata schema equivalent to 3G2's 3GPP2 atom structure. Neither format supports subtitles, chapters, or multiple audio tracks, so no stream data is lost on those fronts. File sizes may increase compared to the original 3G2 if the source was encoded at an extremely low mobile bitrate, since CRF 23 targets visual quality rather than a strict bitrate ceiling.