ASF to FLV converter
Convert ASF to FLV in seconds, free and unlimited. No upload, no sign-up, no watermark: your video never leaves your device.
Last updated
Quick answer: To convert ASF to FLV, add the ASF file to the iHateFiles ASF 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. ASF is a format most software has stopped opening. FLV is not.
Should you convert ASF to FLV?
Yes. ASF is a format most current software no longer opens, so converting it is the reliable way to keep watching it. FLV is a reasonable target; MP4 is the safest.
The picture is re-encoded
An ASF usually holds Windows Media video and audio. 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 ASF artefacts rather than the original.
Where the FLV will play
FLV plays on VLC and very little else since Flash was retired in 2020.
ASF and FLV side by side
| ASF | FLV | |
|---|---|---|
| Inside the file | Windows Media video and audio | Sorenson Spark (FLV1) video with MP3 sound |
| Compression | Lossy | Lossy |
| Carries sound | Yes | Yes |
| Plays on | Needs converting first | VLC and very little else since Flash was retired in 2020 |
| Here | Read only | Read and write |
What usually goes wrong
About the ASF. ASF, WMV and WMA all share the same file signature, so identifying which one you have means looking at the streams inside rather than the first few bytes.
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 ASF to FLV
- Add your ASF 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 ASF to FLV?
Open this page, add your ASF 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 ASF 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 ASF files at once?
Yes. Add as many as you like and they are converted one after another, then offered as a single ZIP.