MKV to ASF Converter

Convert MKV to ASF Online

ASF (Advanced Systems Format) is Microsoft's streaming-era container — the wrapper behind .wmv and .wma files. This tool re-encodes your MKV's video and audio and re-wraps them into an ASF container that older Windows Media workflows and legacy streaming servers expect. It is a deliberately narrow conversion: MKV is a richer container, so anything MKV-specific (multiple audio tracks, soft subtitles, chapters, attachments) does not survive the move to ASF. If you only want a smaller, broadly playable file, MKV to MP4 is the modern choice.

How to Convert MKV to ASF

1. Upload Your MKV File: Drag and drop your .mkv file onto the page or click "+ Add Files." You can queue several clips to convert with the same settings.
2. Choose the Video Codec (Optional): Open Advanced Options to reach the Video Codec dropdown. ASF output defaults to H.264, which is efficient but an uncommon pairing for this container — see the FAQ below. For the classic Windows Media combination, pick WMV 2 (or WMV 1); the Audio Codec then defaults to WMA v2.
3. Set Quality or Resolution (Optional): Use the Preset menu (default "Very High") under File Compression, or switch to Specific file size to hit a byte target. Video resolution presets and Trim let you downscale or export only a clip.
4. Convert and Download: Click "Convert" and download your ASF file. No sign-up, no watermark.

Files are uploaded over an encrypted connection, processed on our servers, and deleted automatically a few hours after conversion — never shared or made public.

MKV vs ASF at a Glance

Frequently Asked Questions

What happens to my MKV subtitles, chapters, and extra audio tracks?

They are not carried into the ASF file. MKV is a feature-rich container that can hold unlimited audio tracks, soft (toggleable) subtitles, chapter markers, and attached fonts or cover art in a single file. ASF was not built around those capabilities, so this conversion keeps one video stream and one audio stream and drops the rest. If you need to keep that material, either pick the audio track you want before converting, or keep the original MKV and treat the ASF as a stripped-down derived copy. To burn a subtitle permanently into the picture instead of losing it, that has to be done as a separate hardsub step — ASF cannot store it as a toggleable track.

Does this output WMV inside the ASF file, or something else?

By default, no — and this surprises people. ASF is only a container, and on this tool the ASF output defaults to the H.264 video codec with WMA v2 audio. H.264-in-ASF is a valid but uncommon combination: it gives you the ASF wrapper while using a far more efficient video codec than classic Windows Media Video. If you actually want the traditional Windows Media pairing — WMV video in an ASF container — open Advanced Options and set the Video Codec to WMV 2 or WMV 1. Both are selectable for ASF output.

Is an ASF file the same thing as a WMV file?

Almost. Microsoft defines ASF as the container, and .wmv is simply an ASF file that carries a video stream (while .wma is an audio-only ASF). They share the same underlying structure and differ mainly in extension and MIME type. If your target system specifically expects a .wmv file rather than a generic .asf, use MKV to WMV instead — that path keeps the same Windows Media container but writes the .wmv extension and defaults to a WMV codec.

Will I lose quality converting MKV to ASF?

Yes, a little — this is a re-encode, not a remux, so the video is decoded and compressed again into one fresh lossy generation. In our testing the loss is usually invisible at the default "Very High" preset, but each round of lossy re-encoding discards some data permanently, so avoid repeatedly converting the same clip back and forth between formats. If preserving the original matters, keep your source MKV and treat the ASF as a derived copy for whatever system needs it.

Why convert MKV to ASF in 2026 instead of MP4?

For almost all general use, you would not — MP4 is smaller, plays everywhere, and is the right default (MKV to MP4 covers that). ASF is the right answer only in narrow, legacy situations: a Windows Media-era workflow, an old streaming server that ingests .asf, or a corporate system standardized on the Windows Media container years ago. MKV is the more capable, openly specified container, so going to ASF is a step sideways into a legacy ecosystem rather than a modernization — choose it only when a specific system demands that container.

How long do my files stay on your servers?

Your MKV upload and the converted ASF file are processed on our servers over an encrypted connection and deleted automatically a few hours after conversion. Nothing is shared, made public, or kept beyond that window, and no account or sign-up is required to convert.