01
ADD YOUR FLV
Drop the FLV file into the box above or choose it from your device.
FLV → MKV / online converter
FLV to MKV Converter
Convert an FLV video to MKV for media servers and players like Plex, Jellyfin and VLC.
01 / how to
How to convert FLV to MKV
02
CONVERT TO MKV
MKV is already selected. Press Convert and wait a few seconds.
03
DOWNLOAD
Save the finished MKV file. The original is deleted from our server.
02 / what you get
What happens to your data
Kept
- Old Flash Video files, such as downloaded web clips and archived recordings, are read
- H.264 video with AAC audio in a Matroska container that plays in VLC, Plex, Jellyfin and most media players
- The original resolution and frame rate are kept
- A phone video recorded sideways or upside down is turned the right way up
- Surround sound (5.1) is kept when the source has it
Good to know
- The video is re-encoded, which is slightly lossy. Only one video track and one audio track are kept; extra audio tracks and subtitles are left out.
- A width or height that is an odd number of pixels is trimmed by one pixel, because video encoders need even sizes.
- HDR video (for example from a recent iPhone) is converted to normal SDR colors, and 10-bit video becomes 8-bit, so it plays everywhere.
- Files up to 150 MB are accepted. Long or very high-resolution videos can take several minutes, and a conversion that runs past about 4 minutes is stopped with a message.
03 / formats
FLV vs MKV
FLV
An FLV file is the old Flash Video format that powered most web video in the 2000s and early 2010s. Flash itself is dead, but the container still shows up in some legacy systems.
Used in: Legacy web video · Old streaming systems
MKV
An MKV (Matroska) file is an open-standard, highly flexible video container — popular for media archiving, torrents, and playback through apps like Plex or Jellyfin.
Used in: Media archiving · Plex & Jellyfin · Torrents
04 / more
More conversions
Have a different file? Open the main converter — it detects the format for you.