WEBM to FLV converter
Convert WEBM to FLV in seconds, free and unlimited. No upload, no sign-up, no watermark: your video never leaves your device.
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Quick answer: To convert WEBM to FLV, add the WEBM file to the iHateFiles WEBM to FLV converter and press Convert. The conversion runs in your browser, so the file is never uploaded, and it is free with no sign-up, watermark or size limit. Re-encodes the picture and sound into a FLV container.
Should you convert WEBM to FLV?
Do this when something specifically needs FLV. The picture is re-encoded, so it costs a little quality; if all you need is a file that plays everywhere, MP4 is usually the better target.
The picture is re-encoded
A WEBM usually holds VP8, VP9 or AV1 video with Vorbis or Opus sound. This writes Sorenson Spark (FLV1) video with MP3 sound into the FLV. Both sides are compressed with loss, so this is a second generation: leave the quality at its default or higher, because the encoder is working from WEBM artefacts rather than the original.
Expect a larger FLV
FLV uses Sorenson Spark (FLV1) video, an older and less efficient codec than a WEBM normally holds. Matching the look takes more bytes, so the file grows. Do it for compatibility with whatever needs FLV, not to save space.
Extra tracks may not survive
A WEBM can carry subtitle tracks. FLV holds one picture and one sound, so this conversion keeps the main video and the first audio track. If you need the subtitles, save them first with Extract Subtitles.
Where the FLV will play
FLV plays on VLC and very little else since Flash was retired in 2020.
WEBM and FLV side by side
| WEBM | FLV | |
|---|---|---|
| Inside the file | VP8, VP9 or AV1 video with Vorbis or Opus sound | Sorenson Spark (FLV1) video with MP3 sound |
| Compression | Lossy | Lossy |
| Carries sound | Yes | Yes |
| Plays on | every modern browser and Android, but not QuickTime or older iPhones | VLC and very little else since Flash was retired in 2020 |
| Here | Read and write | Read and write |
What usually goes wrong
About the WEBM. A browser screen recording is usually a WEBM with a broken duration, so players show it as zero seconds or refuse to seek. Converting it to MP4 rewrites the header and fixes the seeking.
About the FLV. If you have FLV files they are probably old downloads worth rescuing, and converting them to MP4 is the way to keep them watchable.
How to convert WEBM to FLV
- Add your WEBM file. It is read from your disk and stays there.
- Check the settings. The output format is already set to FLV.
- Press convert and the FLV file is saved back to your device.
Questions
How do I convert WEBM to FLV?
Open this page, add your WEBM file, and press convert. The file is decoded and re-encoded by your own browser and saved back to your device. Nothing is uploaded.
Is this WEBM to FLV converter free?
Yes, completely. There is no account, no sign-in, no watermark and no daily limit, because there is no server doing the work. Your own device does it.
Are my files uploaded anywhere?
No. There is no upload endpoint. The conversion runs inside this browser tab, so your file never leaves your device. You can open your browser's network panel and watch: nothing carrying your file is sent.
Is there a file size limit?
No fixed limit. Because the work happens on your machine there is no server quota. The only ceiling is your own device's memory, which for video means very large files may be slow.
Will converting to FLV lose quality?
FLV is a lossy format, so some detail is discarded. The quality control on this page decides how much. The default is set high enough that most people cannot see the difference.
Can I convert several WEBM files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.