How to convert ASF to WEBM
To convert ASF to WEBM, upload your ASF file, choose WEBM as the output format and press Convert. The finished WEBM file is ready to save to your phone or computer in seconds, free, with no watermark and no sign-up. Your file is deleted from our server about 30 minutes after the conversion.
This free online converter turns ASF videos into WEBM files in your browser, with no software to install and no watermark. When the video and audio inside your ASF file can be placed in WEBM as they are, the streams are copied without re-encoding, which is faster and keeps the original quality. Otherwise the video is re-encoded as VP9 video with Opus audio.
Reasons to switch from ASF to WEBM
- Designed for the web and royalty-free
- Plays natively in Chrome, Firefox, Edge and Android
- Efficient VP9 compression
- Plays on: Chrome, Firefox, Edge, Opera, Android and VLC; partial on Safari and iOS
What to expect from this conversion
- Expect a smaller file than the ASF original, because WEBM compresses more efficiently.
- WebM uses VP9, which compresses very well but takes longer to encode than H.264, so large videos need patience.
- ASF is a legacy format, so moving to WEBM makes the video easier to play, edit and share on current devices.
- The first audio track is kept. Subtitle tracks, extra audio tracks and chapters are not included in the converted file.
ASF vs WEBM
| Property | ASF | WEBM |
|---|---|---|
| Full name | Advanced Systems Format | WebM |
| Released | 1999, Microsoft | 2010, Google |
| Generation | Legacy | Modern |
| Typical file size | Medium | Small |
| Plays on | Windows Media Player, VLC and legacy Windows tools | Chrome, Firefox, Edge, Opera, Android and VLC; partial on Safari and iOS |
| Best for | legacy Windows streaming; old media servers | embedding video on your own website; short looping clips and web animations |
Steps to convert ASF to WEBM
- Drop your ASF video file onto the converter, or click to choose it.
- Check that WEBM is selected as the target and adjust the options if you want.
- Press Convert, then download your new WEBM file when it finishes.
Tips for the best result
- Leave Fast mode on to keep the original quality whenever the streams can be copied.
- Pick a lower resolution if the file is for a phone or messaging app.
- Use Mute if you only need the picture.
Frequently asked questions
How do I convert ASF to WEBM?
Upload your ASF file, make sure WEBM is the selected target and press Convert. When the progress bar finishes, download the WEBM file. No account or software is needed.
Is the ASF to WEBM converter free?
Yes. It is free, with no watermark, no sign-up and no daily limit on how many files you convert. The site is supported by ads.
Will I lose quality when converting ASF to WEBM?
Not necessarily. If the video and audio streams already fit inside WEBM, they are copied without re-encoding, so quality stays identical. If the file has to be re-encoded, the High setting keeps almost all visible detail, while Small trades some detail for a smaller file.
Why is my WEBM file smaller than the ASF original?
Expect a smaller file than the ASF original, because WEBM compresses more efficiently. Choosing a lower quality or resolution reduces the size further.
Which devices can play WEBM files?
WEBM files play on Chrome, Firefox, Edge, Opera, Android and VLC; partial on Safari and iOS.
How large a file can I upload?
You can upload videos up to 500 MB. Files are deleted from the server about 30 minutes after conversion.