How to convert a .ASF file online
Three steps, all tab.
Open your file
Drop your .ASF file and every video, audio and subtitle track inside is listed with its codec, resolution, frame rate and language.
Preview
See frames from across your .ASF file before you convert, even when your browser can't play the codec inside.
Convert
Pick MP4, WEBM or MP3, or repack to MKV without re-encoding. Play the result right here, then download it.
What is a .ASF file?
Everything worth knowing about Advanced Systems Format.
An ASF file is Microsoft's Advanced Systems Format container - the same format that underlies Windows Media Video (.wmv) and Windows Media Audio (.wma). On Windows, double-click it and Media Player handles it. On Mac, Linux, Android, or iOS, use the free VLC media player. For broad compatibility, convert it to MP4 with VLC, HandBrake, or FFmpeg; DRM-protected files cannot be converted without the original licence.
Programs that open .ASF files
- Windows
- VLC media player, FFmpeg, Windows Media Player / Media Player
- macOS
- VLC media player
- Linux
- VLC media player, MPlayer / mpv
- Android
- VLC for Android
- iOS
- VLC for Mobile
| Full name | Advanced Systems Format |
|---|---|
| Developer | Microsoft |
| First released | 1999 (Windows Media Technologies 4); originally 'Advanced Streaming Format' |
| Category | Audio & Video |
| MIME type | video/x-ms-asf |
| Signature | 30 26 B2 75 8E 66 CF 11 A6 D9 00 AA 00 62 CE 6C (ASF_Header_Object GUID (30 26 B2 75 …)) |
Related viewers
Other free tools to open and preview your files.
Is my .ASF file uploaded to a server?
No. Your .ASF file is converted for you. The converted file is created in memory,.
Why is conversion slower than desktop software?
Browsers give web pages a single CPU core for this kind of work and no hardware video encoder. Short clips convert in seconds; for long 4K films a desktop app like HandBrake is faster. Use Start and Length to convert just the part you need.
Which output format should I pick?
MP4 plays on every phone, TV and browser. WEBM is an open format that's great for the web. MP3 keeps only the sound. MKV (no re-encode) is instant and lossless, but only changes the container.
Can I keep all audio tracks and subtitles?
The MKV (no re-encode) option copies every track as-is. MP4 and WEBM keep the first video and audio track, which is what most players use.
Why can't some files be converted?
Files protected with DRM (for example purchased iTunes .m4p songs or some .wmv rentals) are encrypted. We can show what's inside, but nobody can convert them without the key.
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