MKV to 3G2 Converter

Convert MKV to 3G2: What This Tutorial Covers

This page re-encodes a Matroska (.mkv) video into .3g2, the 3GPP2 container 3GPP2 defined in January 2004 for CDMA2000 phones — the CDMA twin of GSM's .3gp. It is written for the narrow set of people who genuinely need the CDMA variant in 2026: feeding an actual CDMA-era feature phone, an MMS gateway, or an embedded device or test harness that only ingests .3g2. Be clear-eyed first: the 3G CDMA network 3G2 was built for has been shut down in the US since the end of 2022, so almost everyone reaching for "a smaller MKV that plays everywhere" actually wants MKV to MP4 instead. This page is honest about the cost — 3G2 crushes video to phone-era resolution and bitrate, and it cannot carry MKV's subtitle tracks, chapters, or extra audio languages.

How to Convert MKV to 3G2

1. Upload Your MKV File: Drag and drop, or click "Add Files", to select one or more .mkv videos. Batch is supported, so a folder of clips runs in a single job.
2. Pick the Video Codec: Open Advanced Options and set the Video Codec. The default is H.264, which holds the most detail at 3G2's low bitrates and is read by most post-2008 handsets; the default Audio Codec is AMR, which every 3G2-capable device decodes.
3. Set Resolution and Quality Preset (Optional): Use Preset Resolutions or Width x Height to drop the frame size to something a phone screen expects (176x144 or 320x240 are typical), and use Quality Preset or Specific file size to fit an MMS or storage limit. The Trim panel keeps just one clip.
4. Convert and Download: Click Convert and download the .3g2. No sign-up, no watermark.

Walk-through: Codec, Resolution, and the Tracks MKV Will Lose

3G2 is a low-bandwidth format, so the two settings that decide whether your file plays on the target device are the Video Codec and the resolution. Matching them to the receiving device matters far more than chasing quality.

• Targeting a CDMA phone from roughly 2009 onward: leave the Video Codec on H.264 and audio on the default AMR (or switch audio to AAC if the device supports it). H.264 holds detail far better than the older codecs at the tiny bitrates 3G2 uses.
• Targeting an old CDMA feature phone or an MMS gateway: set the Video Codec to H.263 or MPEG-4, keep audio on AMR Narrow Band, and drop the resolution to 176x144 (QCIF) or 320x240 (QVGA). Many early handsets only decode H.263 at QCIF, and an MMS gateway often rejects anything larger than a few hundred kilobytes.
• Targeting an embedded device or test harness: match whatever its documentation specifies. If it says "H.263 baseline, AMR-NB, QCIF," set exactly that — a higher-quality H.264 file may simply fail to open.

Two honest caveats specific to MKV. First, MKV is a flexible container that often holds several audio languages, soft (selectable) subtitle tracks, and chapter markers; the 3G2 container holds a single video stream and a single audio stream and has no equivalent for the rest, so the conversion keeps one video and one audio track and discards everything else. If you need those subtitles, burn them into the picture first or keep an MKV or MP4 copy alongside the 3G2. Second, this is a lossy re-encode: whatever codec the MKV uses (H.264, HEVC, VP9, AV1) is decoded and re-compressed into 3G2, adding one fresh generation of lossy compression. You can only minimize that by not shrinking the resolution more than the target device needs.

Common Errors and How to Fix Them

• "The 3G2 looks blocky and soft compared to my MKV" — Expected. 3G2 targets phone-era bitrates and small resolutions, so detail is intentionally discarded to hit a tiny file size. If quality matters more than CDMA compatibility, convert with MKV to MP4 instead.
• "My subtitles and second audio track are gone" — Also expected. 3G2 keeps a single video and single audio stream and has no place for MKV's soft subtitles, chapters, or extra languages. Pick the audio language you want before converting, and keep the MKV if you still need the extras.
• "My phone or MMS gateway rejects the file" — The codec or resolution is too modern. Switch the Video Codec to H.263, set audio to AMR Narrow Band, and drop the resolution to 176x144, which the widest range of legacy handsets accept.
• "The output is silent" — The source MKV may carry an audio codec the converter can't map to AMR, or you selected a subtitle or secondary stream as the audio. Re-run with the Audio Codec set explicitly to AMR Narrow Band, or to AAC if the target device supports AAC audio in 3G2.
• "The file is still too big for MMS" — Shorten the clip with the Trim panel, lower the resolution, and use Specific file size to cap the output; MMS payloads are often limited to a few hundred kilobytes.

When This Doesn't Work

If your MKV is corrupted — a truncated download, or a file copied off a failing disk — the converter can't re-encode it and the job will fail. And if you are reaching for 3G2 only because you want a smaller video that still plays on current phones and computers, 3G2 is the wrong target in 2026: it was built for a CDMA network that no longer exists, its codecs and resolution ceiling are dated, and you lose MKV's tracks for nothing. Use MKV to MP4 for a modern, well-compressed, broadly compatible file. 3G2 earns its place only when something on the other end specifically requires the CDMA container. If you are instead trying to bring old CDMA phone footage out of 3G2 into the flexible Matroska container, that is the reverse of this page — see 3G2 to MKV.

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 feature phone, an MMS gateway, or an embedded device or test harness that ingests .3g2. The 3G CDMA network that 3G2 was designed for was retired in the US at the end of 2022 (Verizon shut its CDMA network down on December 31, 2022), so for everyday use MP4 is smaller at equal quality, plays on essentially every current device, and keeps far more of what an MKV holds. If that is what you actually want, MKV to MP4 is the right page. 3G2 is a compatibility target, not a quality or general-purpose 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, MPEG-4 Part 12), so they look nearly identical inside. The split is by network: .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, and H.264 video plus AMR and AAC audio, but .3g2 also defines CDMA speech codecs (QCELP/13K, EVRC, SMV) and drops HE-AAC v2 and AMR-WB+. This page outputs the CDMA variant; if your target needs the GSM one, use MKV to 3GP instead.

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

They are not carried into the 3G2. MKV is a flexible container that can store several audio languages, soft (selectable) subtitle tracks, and chapter markers; the 3G2 container holds a single video stream and a single audio stream and has no equivalent for the rest. The conversion keeps one video and one audio track and drops everything else, so if you rely on those, burn the subtitles into the picture beforehand or keep an MKV or MP4 copy alongside the 3G2.

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

By default this converter writes H.264 video with AMR audio inside the 3G2 container, which suits CDMA handsets from roughly 2009 onward. For older phones you can switch the Video Codec to H.263 or MPEG-4 and keep audio on AMR Narrow Band; if the target device supports it, you can also choose AAC. The 3G2 standard itself also defines CDMA-specific speech codecs such as QCELP, EVRC, and SMV, but H.264 plus AMR is the most broadly playable pairing this tool produces.

Will the 3G2 look worse than my original MKV?

Usually yes, and that is inherent to the format rather than a flaw in the conversion. 3G2 was built for low-bandwidth CDMA mobile delivery, so it uses small resolutions and low bitrates, and re-encoding into it discards detail to hit that tiny size. You can soften the loss by keeping the resolution no smaller than the target device needs and leaving the Video Codec on H.264, but a 3G2 cannot match a full-resolution MKV. In our testing, a one-minute 1080p MKV re-encoded to 176x144 H.263 3G2 came out around a few hundred kilobytes — small enough for legacy MMS but visibly soft, which is exactly the format's design point.

How are my files handled after conversion?

Files are uploaded over an encrypted connection and processed on our servers — no sign-up and no watermark. They are deleted automatically a few hours after conversion and are never shared or made public.