3G2 to HEVC Converter

3G2 to HEVC — Which Output Do You Actually Want?

3G2 is the small, low-resolution 3GPP2 container that CDMA-network phones (Verizon, Sprint, U.S. Cellular) recorded to; HEVC — H.265, standardised as ITU-T H.265 / ISO/IEC 23008-2 and ratified in 2013 — is a high-efficiency video codec, not really a file extension. So the first thing to settle is the wrapper, not the codec. On this page the .hevc download is a Matroska container carrying H.265 video plus your clip's audio (AAC by default), which VLC and mpv open directly while extension-driven consumer apps often refuse until you rename it to .mkv. If you want the smallest file and control the player, .hevc is fine. If you want the clip to open by double-click on a phone, TV, or in QuickTime, convert to 3G2 to MP4 instead — and if you want H.265 under a name every media app recognises, use 3G2 to MKV with the H.265 codec.

Side-by-side: .hevc, .mp4, and .mkv Output

When .hevc Is the Right Choice

• You are archiving a batch of old CDMA phone clips and want the smallest possible files on disk.
• Your playback path is VLC, mpv, or an FFmpeg-based tool, all of which read the file regardless of extension.
• You are feeding the output into another encoder or an editing pipeline that already handles H.265.
• You want a specific bitrate or CRF-style quality target and are comfortable renaming the file to .mkv afterwards.

When to Convert to MP4 Instead

• The clip is going to a phone's gallery app, a smart TV, a browser upload form, or an email attachment.
• You want the file to work on Windows without installing Microsoft's HEVC Video Extensions from the Microsoft Store (a paid add-on unless your PC maker preinstalled the OEM version).
• The source is a 176×144 (QCIF) or 320×240 (QVGA) recording, where the absolute byte savings from H.265 are measured in kilobytes and compatibility is worth more.
• You are sharing with someone else and cannot walk them through renaming an extension.

How to Convert 3G2 to HEVC

1. Upload Your 3G2 File: Drag and drop the .3g2 clip onto the page, or click "Add Files" to browse. .3gp is accepted by the same pipeline, and several files can be queued with one set of settings.
2. Set the Quality Preset: The Video Codec dropdown is limited to H.265 / HEVC here — that is what the output means. Leave Quality Preset on its "Very High (Recommended)" default to stay close to the source, or open File Compression for Target file size (%), Specific file size, Constant Bitrate, Variable Bitrate, Constant Quality, or Constraint Quality.
3. Adjust Video resolution or Trim (Optional): Under Video resolution, "Keep original" is the right call for a 3G-era frame; "Preset Resolutions", "Resolution Percentage", and "Width x Height" are there if a target device needs exact dimensions. Use Trim → Time Range to export only part of the clip.
4. Convert and Download: Click Convert. Files upload over an encrypted connection, are re-encoded on our servers, and are deleted automatically a few hours later — no sign-up, no watermark.

H.265 at a Glance

Frequently Asked Questions

Does the converted .hevc file keep the audio?

Yes. The download is a Matroska container, so the 3G2's soundtrack — typically QCELP, EVRC, AMR, or AAC — is carried across and re-encoded, with AAC as the default and AC3, EAC3, DTS, FLAC, MP2, MP3, Opus, and Vorbis available under Audio Codec. If your output is silent, the source clip had no audio track to begin with. Want only the sound? 3G2 to M4A or 3G2 to MP3 extract it directly.

What can actually play a .hevc file?

VLC, mpv, and other FFmpeg-based players open it as-is, because they inspect the bytes rather than the extension — you get normal duration, seeking, and audio. Phones, smart TVs, QuickTime, and browsers generally refuse it: they judge by the unfamiliar extension, and QuickTime does not read Matroska at all. Renaming the download to .mkv fixes most of those refusals in one step. If you need something that opens everywhere without renaming, convert to MP4.

Will converting 3G2 to HEVC improve the picture?

No. A CDMA-era 3G2 was captured at low resolution and low bitrate, commonly 176×144 (QCIF) or 320×240 (QVGA), and re-encoding cannot recover detail the sensor and encoder never recorded. Every conversion here is a real re-encode, so this is a lossy-to-lossy step: what H.265 buys you is a smaller file at similar perceived quality, not a sharper one. Keep Video resolution on "Keep original" — upscaling a QCIF frame to 1080p adds blur and bytes.

Is H.265 really 50% smaller than H.264?

"Up to" 50% is the headline figure and 25-50% is the honest working range; the saving depends on resolution, motion, and encoder settings. The gains are largest at 4K and on detailed, high-bitrate footage, and smallest on tiny low-bitrate clips like a 3G2 — where the file is already only a few hundred kilobytes, so a 40% saving is a few hundred kilobytes less. If your goal is a specific number, use File Compression → Specific file size rather than trusting a codec-level rule of thumb.

Why is HEVC encoding slower than H.264?

H.265 uses larger, flexibly-partitioned coding tree units, more intra-prediction directions, and better motion modelling — all of which cost computation to search. That is the price of the bitrate saving, and it is why an HEVC job takes noticeably longer than the same clip encoded to H.264. For a short 3G2 clip the difference is seconds; on a long batch it adds up, which is another reason MP4 is the pragmatic choice when size is not critical.

Can I play the .hevc output on Windows without extra software?

Often not directly. Windows 10 and 11 can decode HEVC only when the HEVC Video Extensions component is present — either the free version preinstalled by some PC makers or the paid one in the Microsoft Store — and Windows' built-in player does not read Matroska anyway. The reliable route on Windows is VLC, which handles both the container and the codec. Renaming to .mkv also helps apps that filter by file type.

Is .3g2 the same as .3gp, and can I use this page for both?

Both are built on the ISO base media file format (ISO/IEC 14496-12), but 3GP is 3GPP's format for GSM/UMTS phones while 3G2 is 3GPP2's for CDMA2000 phones, adding EVRC, EVRC-B, EVRC-WB, QCELP (13K), SMV, and VMR-WB audio and dropping HE-AAC v2 and AMR-WB+. This page accepts both extensions. The dedicated twins are 3GP to HEVC and 3GPP to HEVC.

Should I archive old phone clips as HEVC or leave them as 3G2?

If the originals are irreplaceable, keep them: the 3G2 files are already tiny, and every re-encode loses a little more. Converting is worth it when you need the footage to be usable — playable in a modern app, editable, or uploadable — and in that case MP4 usually serves better than .hevc. A reasonable compromise is to keep the untouched 3G2 originals for provenance and generate MP4 or MKV copies for everyday use.

How are my uploaded 3G2 files handled?

Each file is uploaded over an encrypted connection, converted on our servers, and returned to you for download; uploads and results are deleted automatically a few hours afterwards. There is no sign-up, no watermark, and files are never shared or made public. On a long clip the practical bottleneck is upload time rather than the encode, so trimming with Trim → Time Range before converting is the quickest way to speed a job up.