FLV
Flash video
FLV was the format behind web video in the Flash era. Flash Player was retired at the end of 2020, so FLV files no longer play in any browser.
Opens in VLC and little else since Flash Player was retired in 2020
FLV converterFLV to MKV converter, without the upload.
Turn FLV videos into MKV. It is converted in your browser, so the file never leaves your device.
Drop FLV files here
or choose from your computer paste with Ctrl V
from Photos or Files
Ready · other file types work too0 bytes uploaded, ever
Convert to
- On your device · nothing is uploaded
- No account, no email
- Batch and ZIP download
- Free
How to convert FLV to MKV
Add your FLV videos
Drop FLV files onto the box above, or click it to choose them. ToAny reads the file's contents to detect the type, so a wrong extension does not matter.
MKV is already chosen
Press Convert. Open Options first if you want to change the defaults. The work happens in this tab and can take a while for large files.
Download
Save the MKV, or download everything as one ZIP if you converted several files.
Why ToAny
Private by construction
The FLV to MKV converter is part of this page and runs inside your browser. Your videos are never sent to ToAny or to anyone else.
No upload, no queue
Nothing has to travel to a server and back, so work starts the moment you press Convert. How long it takes depends on your device and the size of the file.
Free, without an account
No sign-up, no email address and no watermark. Add several files and download them together as a ZIP.
FLV to MKV: what to expect
FLV no longer plays in any browser now that Flash is gone. MKV can carry several audio and subtitle tracks in one file. FLV is at home in nothing new; it survives in old downloads and stream recordings; MKV is the usual choice for films with several audio and subtitle tracks.
The defaults suit most files. Under Options you can lower the resolution, trade quality against file size, remove the sound and trim the start and end. This is demanding work for a browser: a long or high-resolution file can take several minutes, and your device does all of it, so keep the tab open.
This pair uses the compatibility engine, ffmpeg built for the browser, because FLV is not handled by the browser's built-in codecs. It is a one-off download of about 10 MB that the browser keeps, it is slower than the built-in codecs, and it takes files up to 1 GB.
FLV vs MKV
MKV
Matroska video
MKV is an open container that can hold practically any video and audio format plus multiple subtitle tracks. That flexibility is why it is popular for films, and why Apple devices and browsers refuse it.
Opens in VLC, Plex and many TVs; not iPhones, QuickTime or most browsers
MKV converter| FLVFlash video | MKVMatroska video | |
|---|---|---|
| Stands for | Flash Video | Matroska |
| Type | Video container | Video container |
| Compression | Lossy | Depends on what is inside |
| Usually contains | Sorenson Spark, VP6 or H.264 video with MP3 or AAC audio | Almost anything: H.264, HEVC, AV1, several audio and subtitle tracks |
| Introduced | 2002, by Macromedia (later Adobe) | 2002, by the Matroska project |
| Opens in | VLC and little else since Flash Player was retired in 2020 | VLC, Plex and many TVs; not iPhones, QuickTime or most browsers |
| Best for | Nothing new; it survives in old downloads and stream recordings | Films with several audio and subtitle tracks |
| File extension | .flv | .mkv |
Questions
Are my videos uploaded anywhere?
No. The FLV to MKV conversion runs inside your browser, on your own phone or computer. The file is not sent to ToAny or to anyone else.
Does converting FLV to MKV reduce quality?
It depends on what is inside the FLV. When its video and audio are already in a form MKV can hold, they can be carried over without being compressed again. Otherwise they are re-encoded, which costs a little quality. Under Options you can favour quality or a smaller file.
Can I convert several FLV files at once?
Yes. Add as many as you like, convert them together and download each result or all of them as one ZIP.
How do I convert FLV to MKV on Windows, Mac, iPhone or Android?
The steps are the same everywhere because ToAny runs in the web browser: open this page in a current version of Chrome, Edge, Safari or Firefox, add the FLV file, press Convert and save the MKV. There is nothing to install.
Is there a file size limit?
Yes. FLV to MKV runs on the compatibility engine, which takes files up to 1 GB, and a long clip takes a while because it is slower than the browser's built-in codecs. Beyond that the limit is your device's memory, since nothing is uploaded; a computer copes with large files better than a phone.