Convert FLV to M4V
This makes an M4V out of the FLV you already have. FLV is leftover Flash video from the era before HTML5 players. Your file never leaves your computer.
Need the other direction? Convert M4V to FLV
How to convert FLV to M4V
- 1 Drop your FLV .flv or .f4v file onto the page, or click to browse for it.
- 2 Set the quality, or leave the default, which keeps the file small without anything showing.
- 3 Convert. The work happens on your own machine, so how long it takes depends on your computer and the file.
- 4 Download the M4V, or add more files and do the whole set in one go.
Why convert FLV to M4V
- Essentially MP4, so converting is fast and costs nothing.
- Supports chapters and multiple audio tracks in Apple players.
- Content exported from older Apple software.
- FLV: limited in what it can hold, with no modern features.
FLV compared with M4V
How the two formats differ on the things that decide whether a conversion is worth making.
| Property | FLV | M4V |
|---|---|---|
| File extension | .flv | .m4v |
| Browser support | No browser support | Some browsers |
| Introduced | 2002 | 2005 |
| Developed by | Adobe / Macromedia | Apple |
Quality and what changes
Both formats are lossy, so this is a second generation of compression: the FLV is decoded back to pixels that already carry its artefacts, and M4V then compresses that. The damage compounds rather than cancelling out, which is why repeated round trips visibly degrade an image. Encode at a higher quality than the source used, and convert once from the best copy you have rather than from an already converted file.
- One M4V limitation to keep in mind: non-Apple players may refuse the extension even when the file is fine.
Questions about FLV to M4V
Will converting FLV to M4V lose quality?
A little. Both formats are lossy, so the file is decoded and compressed a second time and the two sets of artefacts add up. At a high quality setting the difference is hard to see, but avoid repeated round trips between lossy formats.
Is my FLV file uploaded anywhere?
No. The whole thing runs inside the browser tab you already have open. Your FLV is read straight from your own disk, converted on your machine and handed back as an M4V. Nothing is sent anywhere, nothing is stored and there is no account.
Is there a file size limit?
There is no server-side limit because no server sees the file. The real ceiling is your device memory, since the input and the output both have to fit in the tab. A few hundred megabytes is usually fine on a desktop machine and considerably less on a phone.
Can I convert several FLV files at once?
Yes. Add as many as you like and they are processed one after another, then offered as separate M4V downloads or as a single ZIP. Speed depends on your own processor rather than on a queue.
Does the converter work offline?
Yes, after the page has loaded once. The engine is cached by the browser, so you can disconnect, reload and keep converting. That falls out of doing the work locally rather than being a separate mode you switch on.