Free online BIK to ASF converter

What the BIK format is

BIK is the filename extension used by Bink Video, a proprietary video format developed by RAD Game Tools. Game studios commonly use it for prerendered cutscenes, menus, advertisements, and other video played inside Windows, console, and older game releases. BIK files may contain Bink video with Bink audio, and their codec parameters vary between Bink versions and individual games.

You usually encounter a BIK file in a game's installation directory or extracted game-media archive rather than from a camera or general-purpose video editor. Standard media players and editors may not decode every BIK variant, so conversion software must include Bink demuxing and decoding support.

What the ASF format is

ASF, or Advanced Systems Format, is a Microsoft media container designed for streaming and playback of synchronized audio and video. It commonly stores Windows Media Video and Windows Media Audio streams, using extensions such as .asf, .wmv, and .wma for related workflows.

ASF is useful when a legacy Windows program, media server, or hardware player expects Microsoft streaming media. Its metadata, timestamps, and streaming-oriented structure can be preferable to BIK for Windows Media playback, but ASF does not preserve Bink as a universally playable native stream. The BIK content normally has to be re-encoded.

How to actually convert BIK to ASF

FFmpeg is the practical desktop tool for this conversion when the installed build includes Bink decoding and ASF encoding. Open a terminal in the folder containing the source file and run:

ffmpeg -i input.bik -map 0:v:0 -map 0:a? -c:v wmv2 -b:v 2M -c:a wmav2 -b:a 128k output.asf

Replace input.bik with the source filename. The command decodes the first video stream, includes audio when present, encodes video as WMV2, encodes audio as WMAV2, and places both streams in an ASF container. Adjust -b:v 2M to control video quality and -b:a 128k for audio bitrate; the original BIK bitrate and resolution can be inspected first with:

ffprobe input.bik

If the source has no audio, omit -map 0:a? and the audio options:

ffmpeg -i input.bik -map 0:v:0 -c:v wmv2 -b:v 2M output.asf

If FFmpeg reports that it cannot decode the input, install a current full build and test the file with ffmpeg -decoders | findstr bink on Windows or ffmpeg -decoders | grep bink on Linux and macOS. A BIK variant without available decoder support cannot be converted by that installation.

For a browser-based option, 101convert.com can convert the file for free without installing software. Upload the BIK file, select ASF as the output format, start the conversion, and download the resulting file.

Quality, compatibility, and limitations

Because WMV2 and WMAV2 are different codecs from Bink, this process is lossy re-encoding; it cannot retain the exact original frames or audio samples. Keep the source resolution and frame rate unless the target device requires lower values, and choose a higher video bitrate for text-heavy or fast-moving cutscenes.

Some BIK files contain game-specific audio or unusual frame timing that general-purpose converters may decode imperfectly. Check the ASF from beginning to end, including audio synchronization and looping behavior. ASF also does not reproduce game-engine features such as subtitles, interactive triggers, alpha effects, or playback logic stored outside the video stream.