Convert 3GP to MKV Online Free

Convert 3GP mobile video files to Matroska MKV format for modern media player compatibility, Kodi libraries, and open-format video archiving. ChangeThisFile handles conversion with FFmpeg on secure servers.

Quick Answer

ChangeThisFile converts 3GP to MKV free using FFmpeg on secure servers. Your mobile 3GP uploads with encrypted transfer, converts server-side to Matroska format, and is auto-deleted after download. No signup required — private and completely free.

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Convert 3GP to Matroska

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3GP vs Matroska: Format Comparison

Key differences between the two formats

Feature3GPMKV (Matroska)
Full Name3rd Generation Partnership ProjectMatroska Video
Designed ForMobile video sharingDesktop media archiving
Video CodecH.263, H.264, MPEG-4H.264, H.265, VP9, AV1
Audio CodecAMR-NB, AACAAC, FLAC, AC-3, Opus
Subtitle SupportNoneSRT, ASS, PGS and more
File SizeVery smallVaries (quality-dependent)
Modern Player SupportLimitedVLC, Kodi, MPC-HC, and more
Multi-Track SupportNoYes

When to Convert

Common scenarios where this conversion is useful

Kodi and HTPC Media Library

Convert 3GP mobile recordings to MKV for inclusion in Kodi, Plex, or other home theater software that treats MKV as the primary video format.

Long-Term Mobile Video Archive

Preserve old 3GP mobile video recordings in the open Matroska format for better long-term compatibility with modern media players and systems.

Adding Subtitle Tracks

Convert 3GP to MKV to then mux in subtitle files (SRT, ASS) using MKVToolNix, taking advantage of Matroska's superior subtitle capabilities.

Modern Desktop Playback

Move 3GP clips from a phone archive to desktop format by converting to MKV, playable in VLC and most modern media players without plugins.

Consistent Video Library Format

Standardize a mixed collection of 3GP mobile clips into MKV format for organized, consistent library management.

How to Convert 3GP to Matroska

  1. 1

    Upload Your 3GP File

    Click or drag your 3GP mobile video to the upload area. The file is transmitted to ChangeThisFile's servers using HTTPS encryption.

  2. 2

    Server-Side MKV Conversion

    FFmpeg processes your 3GP into a Matroska MKV container, transcoding H.263 or H.264 video to H.264 and audio to AAC for modern media player compatibility.

  3. 3

    Download Your MKV File

    Your Matroska MKV is ready to download when conversion finishes. The original 3GP is permanently deleted from our servers immediately after.

Frequently Asked Questions

MKV is a modern, open container widely supported by VLC, Kodi, and all major media players. Converting 3GP to MKV provides better desktop playback, subtitle support, and future-proof archiving.

The quality is limited by the source 3GP resolution and bitrate. MKV can contain the same data, but converting doesn't add quality that wasn't in the 3GP source.

Yes. Use MKVToolNix or mkvmerge to mux SRT or ASS subtitle files into the converted MKV, which is one of the primary advantages of the Matroska format.

FFmpeg handles H.263, H.264, and MPEG-4 video in 3GP files, along with AMR-NB and AAC audio codecs.

Files up to 50MB are accepted. 3GP files are usually very small, so this is rarely a constraint.

Yes. Uploads are encrypted with HTTPS and files are deleted automatically after your download. No data is retained.

VLC, MPC-HC, Kodi, mpv, PotPlayer, and Windows 11's native player all support MKV natively.

Yes. The output MKV matches the source 3GP resolution and frame rate.

Yes. VLC for Android and iOS can play MKV files. Many modern Android devices also support MKV natively.

Yes. ChangeThisFile is completely free — no accounts, subscriptions, or watermarks.

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