FLV to MKV - Online Video Converter
Convert FLV to MKV online. Private, client-side - no uploadrequired. Batch conversion, quality presets, codec control.
About FLV to MKV
Convert FLV to MKV. FLV is Adobe's Flash-video container carrying Sorenson Spark or H.264 streams. 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 FLV to MKV?
- Smaller files with MKV lossy compression.
- Keep animation and transparency where supported.
- Private, no upload - runs in your browser.
FLV vs MKV
| Animation | Yes | Yes |
|---|---|---|
| Transparency | No | Yes |
| Compression | lossy | lossy |
| Typical use | FLV is Adobe's Flash-video container carrying Sorenson Spark or H.264 streams. | MKV is an open container holding multiple video, audio, and subtitle tracks. |
When not to convert FLV to MKV
- Skip MKV for archival masters: lossy compression discards detail, so keep the FLV original.
- Keep a master copy: repeated exports stack small losses, so archive FLV before batch MKV shares.
Limits
Starting point: FLV - FLV is Adobe's Flash-video container carrying Sorenson Spark or H.264 streams. Flash-era players are gone, so convert for current browsers. Only the selected tracks carry over, so pick audio and subtitles first. Encode MKV (H.264 / AAC) from FLV 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.