H.264 to MKV - Free Online Video Converter
Convert H.264 to MKV online for free. Private, client-side - no upload required. Batch conversion, quality presets, codec control.
About H.264 to MKV
Convert H.264 to MKV. H.264 is the AVC codec behind most MP4 and broadcast video. MKV is an open container holding multiple video, audio, and subtitle tracks. Only the selected tracks carry over, so pick audio and subtitles first..
Why convert H.264 to MKV?
- Smaller files with MKV lossy compression.
- Keep animation and transparency where supported.
- Free, private, no upload - runs in your browser.
H.264 vs MKV
| Animation | Yes | Yes |
|---|---|---|
| Transparency | No | Yes |
| Compression | lossy | lossy |
| Typical use | H.264 is the AVC codec behind most MP4 and broadcast video. | MKV is an open container holding multiple video, audio, and subtitle tracks. |
When not to convert H.264 to MKV
- Skip MKV for archival masters: lossy compression discards detail, so keep the H.264 original.
- Keep a master copy: repeated exports stack small losses, so archive H.264 before batch MKV shares.
Limits
Starting point: H.264 - H.264 is the AVC codec behind most MP4 and broadcast video. Annex-B headers usually import cleanly into MP4. Only the selected tracks carry over, so pick audio and subtitles first. Encode MKV (H.264 / AAC) from H.264 at a bitrate near the source, and confirm the audio track before converting.
How conversion works
Conversion runs entirely in your browser with FFmpeg WASM. Files never leave your device.