Private Online Tools

Drop your file hereto convert it

Nothing is uploaded - the tools run right here

Convert FLV to MP4 without uploading it

Turn an FLV file into MP4 - here in this tab, with nothing uploaded.

How to convert FLV to MP4

  1. Drop your FLV file in.
  2. MP4 is already selected - press Convert.
  3. Save the MP4 file.

Why this one stays private

Converting a video elsewhere means uploading the whole thing, waiting, and trusting a stranger's server with footage that may not be yours to hand over. The conversion happens here instead.

Questions

Why convert FLV to MP4?

FLV is a Flash-era container you now mostly meet when rescuing something old. MP4 is the format everything plays, and the safe answer when you are not sure. Converting is how you move a file from the first situation to the second.

What will the MP4 file contain?

H.264 video and AAC sound - the pairing every phone, browser, TV and editor plays.

Is the picture re-encoded?

Usually not. An FLV file normally carries H.264 video, which MP4 can hold as it is, so the picture is copied across untouched and the conversion takes seconds. Only a file holding something else is re-encoded.

Is the sound kept?

Yes. The audio track comes across with the picture - copied when MP4 can hold it as it is, converted when it cannot.

Can a browser really open FLV files?

Not on its own - Chrome, Firefox and Safari cannot play FLV, which is why most in-browser converters turn FLV away or quietly upload it. This page brings its own decoder: FFmpeg, compiled to WebAssembly and fetched from this site (10 MB, once) the first time you convert. After that the FLV file is read entirely in this tab.

How long does it take?

Repackaging takes seconds. A full re-encode runs in this tab on one processor core, so a long HD video takes a while - but there is no upload or download to wait for.

The same tool, other formats