Convert MPEG-4 Part 14 (.mp4) to Matroska Video (.mkv) online for free. Fast, secure video conversion with no watermarks or registration.
Conversion settings — add a file to adjust
Upload your .mp4 file by dragging it into the upload area or clicking to browse.
Choose your output settings. The default settings work great for most files.
Click Convert and download your .mkv file when it's ready.
MP4 to MKV conversion repackages your MPEG-4 video into the Matroska container format. MKV is an open-standard container that can hold virtually unlimited numbers of video, audio, and subtitle tracks in a single file. Unlike MP4, which has restrictions on supported codecs, MKV accepts everything from H.264 and H.265 to VP9, AV1, FLAC, DTS, and bitmap subtitles.
Our converter performs a stream copy by default — remuxing the existing video and audio streams from the MP4 into an MKV container without re-encoding. This is essentially instant and produces zero quality loss. The MKV container adds support for features like ordered chapters, soft subtitles in ASS/SSA format, and multiple audio tracks.
MKV is the format of choice for media archivists and home theater enthusiasts. It supports features that MP4 cannot: multiple subtitle tracks in various formats (SRT, ASS, VobSub), lossless audio codecs (FLAC, DTS-HD MA, TrueHD), chapter navigation with ordered chapters, and tagging systems for detailed metadata. If you are building a media library managed by Plex, Jellyfin, or Kodi, MKV is the preferred container because it holds all tracks in one file without compromise.
FFmpeg uses -c copy to remux MP4 streams into the MKV container without transcoding. The Matroska container uses EBML (Extensible Binary Meta Language) for its structure, which is more flexible than MP4's atom-based layout. MKV supports an unlimited number of tracks, ordered chapters via XML chapter files, segment linking for split-file playback, and rich tagging with the Matroska tag specification. CRC-32 checksums can be embedded per cluster for data integrity verification.
When remuxing (stream copy), quality is identical to the source MP4 — no re-encoding occurs. The video and audio bitstreams are transferred verbatim into the new container. File size may differ by a few kilobytes due to the different container overhead, but the media data is unchanged.
| Device | MP4 | MKV |
|---|---|---|
| Windows PC | Native | Partial |
| macOS | Native | Partial |
| iPhone/iPad | Native | Partial |
| Android | Native | Partial |
| Linux | Partial | Partial |
| Web Browser | Native |
Resolution: 1920x1080
Bitrate: 8-12 Mbps
H.264 recommended for fast processing
Resolution: 1080x1080
Bitrate: 3.5 Mbps
Square or 9:16 for Reels
Resolution: 1080x1920
Bitrate: 4 Mbps
9:16 vertical, under 60s ideal
Resolution: 1280x720
Bitrate: 5 Mbps
Under 140s, 512MB max
Resolution: 960x540
Bitrate: 2 Mbps
16MB limit for standard, 64MB for document
Resolution: 1280x720
Bitrate: 4 Mbps
MP4 to MKV is a quick remux that unlocks Matroska's rich feature set — multiple tracks, flexible subtitle support, chapters, and universal codec compatibility — without touching your actual video or audio quality.
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Hoạt động mọi nơi
| No |
8MB free, 50MB Nitro
Mọi trình duyệt, mọi thiết bị
| Tính năng | MP4 | MKV |
|---|---|---|
| Tên đầy đủ | MPEG-4 Part 14 | Matroska Video |
| Phần mở rộng | .mp4 | .mkv |
| Phù hợp nhất cho | Universal compatibility | Multiple audio tracks |