Convert FLV to MP4
Flash is gone, and the FLV files left on old drives will not open in anything. They are read here — Sorenson Spark, VP6, H.264, MP3, AAC, Nellymoser and Flash ADPCM — and written out as MP4 files that play normally.
- Processed on your device
- No upload, no waiting
- No signup, no watermark
How it works
Add your FLV
Drop the file, or an F4V. The codecs inside are named for you.
Let it convert
Old Flash video is decoded and re-encoded as H.264; H.264 inside an FLV is copied across untouched.
Download the MP4
A normal video file again, playable on anything.
Frequently asked questions
How can this open a file even VLC struggles with?
The demuxers and decoders from ffmpeg are compiled to WebAssembly and run inside this page, so the same code that opens a 2007 Flash recording on a desktop runs in your browser — without installing anything.
Is my file uploaded?
No. Decoding and encoding both happen on your device.
The recording has terrible sound. Will this fix it?
No tool can add detail that was never recorded — Nellymoser speech sound is very low quality by design. It is decoded faithfully and written as AAC, so it will sound the same, and finally play.
Why is the picture small?
Flash video was usually 320×240 or 480×360. The original size is kept, because enlarging it only makes the blur bigger. Any player can scale it up if you want it bigger on screen.
What about the sound being out of step?
FLV timestamps are often irregular. Both tracks are rebuilt on one clock from the file's own timestamps, which fixes the drift that made these recordings so hard to watch.
Do screen-recorded FLVs work?
Flash Screen Video is not in this build, so those files are refused with a clear message rather than converted into mush. Everything else — Spark, VP6 and H.264 — works.
Good to know: Flash Screen Video (codecs 3 and 7) and Speex sound are not supported. Cue points and Flash metadata are dropped; the video and sound are what comes across.