Free Online ASF Converter
The Windows Media container, routinely skipped by modern players.
Up to 50 MB per file. Sign up free to convert files up to 100 MB.
| File name | Size | Convert to |
|---|
Checking files and selected output formats.
How to convert ASF files online
Convert Windows ASF video to MP4, MKV, or MOV for reliable playback.
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1
Upload your ASF file
Add your ASF (Advanced Systems Format) file - Microsoft’s container often used for WMV video. It plays poorly outside Windows Media Player.
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2
Select a modern format
Choose MP4 for universal playback, MKV for a flexible container, or MOV for Apple devices and editing.
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3
Download your video
Download the converted file and play it on any device. Uploads are deleted within 1 hour.
Video Format Comparison
Choose the right output format when converting ASF video files.
| Format | Compression | File size | Compatibility | Best For |
|---|---|---|---|---|
| MP4 | H.264/H.265 | Small–medium | Universal | Sharing, streaming, social media |
| MOV | H.264/ProRes | Medium–large | Apple, QuickTime | Mac editing, iPhone recordings |
| MKV | Multiple codecs | Large | PC, media players | High-quality archiving, subtitles |
| WebM | VP8/VP9 | Small | Web browsers | Web embedding, HTML5 video |
| AVI | Various | Large | Windows, legacy devices | Legacy compatibility, editing |
Reasons to convert ASF files
ASF plays best in Windows Media Player and struggles elsewhere. Convert to MP4 so your video works on Mac, iPhone, Android, and browsers.
Convert ASF to MP4 or MOV for reliable import into modern editors that don’t handle the ASF container well.
Convert ASF to MP4 to upload to video platforms and send through messaging apps without compatibility warnings.
Batch-convert ASF and WMV-in-ASF files to MP4 so an entire archive uses one widely-supported format.
Move video off Microsoft’s ageing ASF container into MP4 for long-term, cross-platform playback.
Convert ASF video online, no desktop apps, no plugins. Files up to 100 MB are always free, and all videos are deleted from our servers within 1 hour.
About the ASF Format
ASF, or Advanced Systems Format, is Microsoft's container from the late 1990s, designed for streaming over unreliable connections. It normally holds WMV video or WMA audio, and the extensions .asf.wmv and .wma all describe the same underlying container with different payloads.
ASF was built for Windows Media Player and shows its origins: playback outside the Microsoft ecosystem is patchy, no browser supports it, and some files carry DRM that blocks conversion entirely. For anything you want to keep, MP4 with H.264 is the sensible destination, broadly supported, better compression, and readable by every editor. If a particular file refuses to convert, DRM is the most likely reason.