MKV to 3G2 Converter

MKV to 3G2 Converter

Matroska (.mkv) and 3GPP2 (.3g2) sit at opposite ends of the container spectrum. MKV is an open, deliberately unbounded container — it holds an unlimited number of video, audio, picture and subtitle tracks in one file — and it was formally published as IETF RFC 9559 in October 2024. 3G2 is the 3GPP2 file format written for CDMA2000 handsets, engineered to fit a watchable clip into a few hundred kilobytes on a 2000s mobile network.

Converting MKV to 3G2 is therefore always a full re-encode into a much smaller box, and it is only worth doing when something on the receiving end genuinely requires the CDMA container: an old Verizon- or Sprint-era feature phone, an MMS gateway, or an embedded device or test harness that ingests .3g2 and nothing else. If what you actually want is a smaller MKV that plays everywhere in 2026, MKV to MP4 is the page you want instead — 3G2 costs you resolution, bitrate, and every track MKV was built to carry.

MKV (Matroska) Format at a Glance

3G2 (3GPP2) Format at a Glance

How to Convert MKV to 3G2

1. Upload Your MKV File: Drag and drop your .mkv videos onto the page or click "+ Add Files". Several files can be queued and converted with the same settings.
2. Set the Video Codec and Audio Codec: Open the advanced options. Video Codec defaults to H.264, which holds the most detail at 3G2's low bitrates; Audio Codec defaults to AMR, which every 3G2-capable handset decodes.
3. Downscale and Cap the Size (Optional): Under Video resolution, pick Preset Resolutions for 144p or 240p, or Width x Height to enter an exact frame size such as 176×144. Use Quality Preset or Specific file size to land under a hard cap, and Trim → Time Range to keep only the seconds you need.
4. Convert and Download: Click "Convert" and download the .3g2. Files upload over an encrypted connection, are processed on our servers, and are deleted automatically after a few hours — no sign-up, no watermark.

Matching Codec and Resolution to the Target Device

3G2 is a low-bandwidth format, so the two settings that decide whether the file opens on the receiving device are the video codec and the frame size — matching them to the target matters far more than chasing quality that the container cannot hold anyway.

• A CDMA handset from roughly 2009 onward: leave Video Codec on H.264 and Audio Codec on the default AMR, and drop the resolution to 320×240 (QVGA) or 240p.
• An early CDMA feature phone or an MMS gateway: set Video Codec to H.263, keep audio on AMR Narrow Band, and use Width x Height to set 176×144 (QCIF). Early handsets frequently decode only H.263 at QCIF, and MMS payloads are often capped at a few hundred kilobytes.
• An embedded device or test harness: match whatever its documentation specifies. If it asks for "H.263, AMR-NB, QCIF", set exactly that — a higher-quality H.264 file may simply refuse to open.
• Never upscale. If the MKV is 1080p, going down to QVGA is the whole point; going the other way wastes bitrate on pixels the source never had.

Frequently Asked Questions

Why would I convert MKV to 3G2 in 2026 instead of MP4?

Only when something on the receiving end specifically requires the CDMA container — an old Verizon- or Sprint-era feature phone, an MMS gateway, or an embedded device that ingests .3g2 and nothing else. The networks 3G2 was designed around are gone in the US: T-Mobile retired Sprint's CDMA network in a phased shutdown through the first half of 2022, and Verizon's own support page states that as of January 3, 2023 it has decommissioned its CDMA network. For any general-purpose use, MP4 is smaller at equal quality, plays on essentially every current device, and keeps far more of what an MKV holds — so MKV to MP4 is the better target. 3G2 is a compatibility format, not a quality one.

What is the difference between .3g2 and .3gp?

Both are structurally based on the same ISO base media file format (ISO/IEC 14496-12), so they look nearly identical inside. The split is by network family: .3gp is the 3GPP container for GSM/UMTS phones, while .3g2 is the 3GPP2 container for CDMA2000 phones — in the US, older Verizon and Sprint handsets. They share H.263, MPEG-4 Part 2 and H.264 video plus AMR and AAC audio, but .3g2 additionally defines CDMA speech codecs such as 13K (QCELP) and EVRC, and it does not define HE-AAC v2 or AMR-WB+ the way 3GP does. A device that demands one extension will often refuse the other, so if your target is a GSM-era phone use MKV to 3GP instead.

Which video and audio codecs does the 3G2 output use?

H.264 video with AMR audio by default, which suits CDMA handsets from roughly 2009 onward. We checked the option surface for this specific pair: the Video Codec dropdown offers exactly four choices — H.263, H.264, MPEG-4 and Xvid — and Audio Codec offers AAC, AMR Narrow Band and AMR Wide Band. For older handsets, H.263 plus AMR Narrow Band is the safest pairing; AAC is worth trying only if the target device's documentation says it supports AAC in 3G2.

What happens to my MKV's subtitles, chapters, and extra audio tracks?

They are not carried across. MKV can hold an unlimited number of audio languages, soft (selectable) subtitle tracks and chapter markers; the conversion writes a single video stream and a single audio stream into the 3G2 and drops the rest. The 3GPP2 format does define a 3GPP timed-text track type, but handset support for it was patchy and this converter does not produce one. If you need the subtitles on screen, burn them into the picture before converting, and keep the original MKV or an MP4 copy for everything else.

What resolution should I use for an old CDMA handset?

176×144 (QCIF) is the most universally accepted frame size on early CDMA feature phones, and 320×240 (QVGA) is a reasonable target for later ones. Enter either through Width x Height; the Preset Resolutions list starts at 144p, so exact QCIF or QVGA dimensions need the manual fields. Going smaller than the device's screen buys you a smaller file but nothing else, and going larger is the most common reason a handset refuses to open a file that otherwise looks correct.

Is converting MKV to 3G2 always a re-encode?

Yes. There is no stream-copy path here: MKV files typically carry H.264, HEVC, VP9 or AV1 video with AAC, FLAC or Opus audio, and only H.263, MPEG-4 Part 2 and H.264 video with AMR or AAC-LC audio are valid inside a 3G2. Even in the rare case where the MKV already holds baseline H.264, the audio almost always has to be re-encoded to AMR, and the resolution usually has to come down. Convert once from the highest-quality source you have rather than stacking conversions.

Will the 3G2 look worse than my original MKV?

Almost always, and that is the format working as designed rather than a fault in the conversion. 3G2 was built for low-bandwidth CDMA delivery, so it pairs small frame sizes with low bitrates, and a 1080p MKV re-encoded to QCIF has discarded roughly 98% of its pixels before the encoder even starts. You can limit the loss by keeping the resolution no smaller than the target device needs and leaving Video Codec on H.264, but a 3G2 cannot approach a full-resolution MKV — if quality matters more than CDMA compatibility, convert to MP4.

Can a modern phone or computer play a .3g2 file?

Usually yes, through a general-purpose player: VLC, mpv and most desktop media players read 3G2 without complaint because it is an ISO-base-media file at heart. Native browser playback is the weak spot — MDN lists Firefox for Android as the only browser with built-in 3GP/3G2 support — so a .3g2 is a poor choice for anything you plan to embed on a web page or hand to a colleague. If you have received a .3g2 and want it in a flexible container instead, 3G2 to MKV is the reverse of this page.

How are my files handled after conversion?

Files are uploaded over an encrypted connection and processed on our servers — there is no sign-up and no watermark added. They are deleted automatically a few hours after conversion and are never shared or made public. Because 3G2 outputs are tiny, the slow part of this job is almost always uploading the source MKV rather than the encode itself.