Convert 3G2 to MTS — Free Online Tool
Convert 3G2 files from older CDMA mobile devices into MTS (AVCHD) format, re-encoding the H.264 video and AAC audio into an MPEG-2 Transport Stream container compatible with professional camcorder workflows and broadcast editing software.
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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 lightweight MP4-derivative container built for CDMA mobile networks (Verizon, Sprint-era phones), typically carrying H.264 video and AAC audio at low bitrates optimized for cellular transmission. MTS uses an MPEG-2 Transport Stream wrapper — the same container used by Sony and Panasonic AVCHD camcorders — which packages H.264 video and AAC audio differently, with transport stream packetization designed for broadcast reliability and frame-accurate editing. During this conversion, FFmpeg re-encodes both streams: the video is decoded from its mobile-compressed H.264 and re-encoded into a CRF 23 H.264 stream suited for the MTS container, while the AAC audio is re-encoded at 128k bitrate. Because 3G2 files are typically recorded at very low resolutions and bitrates (often 176×144 or 320×240), the output MTS file will preserve the source resolution rather than upscaling — quality is bounded by what the original 3G2 captured.
What Each Flag Does
| Flag | What it does |
|---|---|
ffmpeg
|
Invokes the FFmpeg program, the open-source multimedia processing engine that powers this conversion both in the browser (via FFmpeg.wasm) and on the desktop command line. |
-i input.3g2
|
Specifies the input file — a 3G2 container from a CDMA mobile device, which 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 mobile-compressed H.264 video from the 3G2 into a fresh H.264 stream packaged appropriately for the MPEG-2 Transport Stream container used by MTS. |
-c:a aac
|
Sets the audio encoder to AAC, re-encoding the AAC audio from the 3G2 source into a new AAC stream compatible with the AVCHD/MTS audio specification. |
-crf 23
|
Sets the Constant Rate Factor for the libx264 video encode to 23 (the default), providing a balance between file size and quality. For already-compressed 3G2 mobile footage, lowering this to 18 can reduce additional generation loss from the re-encode. |
-b:a 128k
|
Sets the audio bitrate to 128 kilobits per second for the AAC output stream, a standard quality level that is appropriate for the typically mono or low-quality audio captured by CDMA mobile handsets in 3G2 format. |
output.mts
|
Specifies the output filename with the .mts extension, which triggers FFmpeg to write an MPEG-2 Transport Stream container — the AVCHD format used by Sony and Panasonic camcorders and recognized by professional video editing applications. |
Common Use Cases
- Importing old CDMA phone videos (from early Verizon or Sprint devices) into Sony Vegas or Premiere Pro, which recognizes MTS as a native AVCHD format for timeline editing
- Archiving a collection of 3G2 clips from a legacy mobile device into MTS so they can be organized alongside footage from a Sony Handycam or Panasonic AG camcorder
- Preparing 3G2 video evidence or documentation clips for ingestion into broadcast-grade media asset management systems that require AVCHD/MTS input
- Converting mobile-recorded 3G2 clips into MTS for use with Sony's PlayMemories or Catalyst Browse software, which is optimized for the AVCHD/MTS format
- Migrating personal 3G2 home videos into MTS as part of a long-term archival workflow where MPEG-2 Transport Stream containers are preferred for their resilience to partial file corruption
Frequently Asked Questions
No — this conversion will not improve the visual quality of the original 3G2 footage. Early CDMA phones often recorded at resolutions as low as 176×144 or 320×240 with heavily compressed H.264, and re-encoding into MTS cannot recover detail that was never captured. The output MTS file will match the source resolution and reflect the same quality ceiling. If anything, the re-encoding step introduces a small additional generation of lossy compression, so using a lower CRF value (e.g., CRF 18) can help minimize that added loss.
MTS is a container format, and while this conversion produces a valid MPEG-2 Transport Stream with H.264 and AAC — exactly as AVCHD specifies — the source 3G2 content was recorded at mobile-phone bitrates and resolutions, not at the 17–24 Mbps typical of a Handycam. Editing software may accept the file as MTS but the video will still reflect its mobile origins: lower resolution, softer image, and potentially choppy framerates if the original 3G2 had variable frame timing.
3G2 does not support subtitles or chapter markers in practice, so there is nothing to carry over. MTS does support subtitles, but since the source format lacks them entirely, the output MTS file will contain only the video and audio streams. If you need to add subtitles to the MTS output, you would need to include a separate subtitle track using additional FFmpeg flags after the conversion.
Video quality is controlled by the -crf flag. The default is 23, which balances file size and quality well for most sources. Lower values produce higher quality at larger file sizes — for a 3G2 source you might try CRF 18 to minimize re-encoding loss, since the source is already heavily compressed. Higher values like 28 or 35 will compress further but may introduce visible blocking on already-low-resolution mobile footage. Change it by replacing '23' in the command: for example, 'ffmpeg -i input.3g2 -c:v libx264 -c:a aac -crf 18 -b:a 128k output.mts'.
Yes. On Linux or macOS, you can loop over all 3G2 files in a directory with: 'for f in *.3g2; do ffmpeg -i "$f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "${f%.3g2}.mts"; done'. On Windows Command Prompt, use: 'for %f in (*.3g2) do ffmpeg -i "%f" -c:v libx264 -c:a aac -crf 23 -b:a 128k "%~nf.mts"'. The browser-based tool processes one file at a time, so the FFmpeg command is especially useful for batch workflows involving large collections of archival 3G2 files.
The -movflags +faststart flag is specific to MP4-family containers (including 3G2 and MOV) and moves the moov atom to the beginning of the file to enable progressive web streaming. MTS uses an MPEG-2 Transport Stream structure, which is inherently packet-based and does not use a moov atom — so this flag is neither applicable nor needed for MTS output. The transport stream format was designed from the ground up for streaming and broadcast, so no equivalent optimization flag is required.
Technical Notes
3G2 and MTS share H.264 video and AAC audio as codec choices, but their containers are architecturally very different. 3G2 derives from the MPEG-4 Part 12 ISO base media file format — essentially a trimmed-down MP4 optimized for CDMA transmission, with a moov atom structure and support for 3GPP2-specific metadata like location tags from the originating handset. MTS wraps streams in MPEG-2 Transport Stream packets (188-byte TS packets), a format designed for broadcast robustness where partial file loss doesn't corrupt the entire stream. This conversion re-encodes both video and audio rather than stream-copying, because even though both formats share H.264 and AAC, the stream packaging and timing models differ enough that a simple remux is not reliable. One notable limitation: 3G2 does not support multiple audio tracks, so any multi-language audio workflows will need to start fresh in the MTS output. Additionally, 3G2 files from older CDMA phones sometimes contain proprietary vendor metadata (carrier branding, device model tags) that will be discarded during the conversion to MTS, which uses different metadata structures aligned with the AVCHD specification. File sizes for the output MTS are typically comparable to or slightly larger than the input 3G2, depending on how aggressively the original was compressed for mobile delivery.