Free online ASF to XVID converter

What the ASF format is

ASF, or Advanced Systems Format, is a Microsoft multimedia container designed for streaming and playback over networks. It commonly contains Windows Media Video (WMV) and Windows Media Audio (WMA), with metadata, indexing, and streaming features stored alongside the media streams.

Files with the .asf extension are found in older Windows Media collections, downloads, screen recordings, and broadcasts. Windows Media Player and older Microsoft encoding tools created many ASF files; some files use .wmv or .wma instead, even though those formats are based on ASF. ASF is a container, so the exact codecs, frame rate, resolution, and audio format must be inspected before conversion.

What the Xvid format is

Xvid is an MPEG-4 Part 2 video codec, not a container format. In practical file conversions, Xvid video is usually placed in an AVI container, producing a file such as video.avi that uses the Xvid codec for its video stream.

Xvid is useful for older televisions, DVD players, media players, and editing applications that support AVI and MPEG-4 Part 2. It provides smaller files than uncompressed video and can preserve acceptable quality at moderate bitrates. It is less suitable than H.264 or H.265 for modern devices because those codecs generally provide better quality at the same file size.

How to actually convert ASF to Xvid

FFmpeg is the most controllable desktop option. Install a current FFmpeg build, place the ASF file in an accessible folder, and run this command from that folder:

ffmpeg -i input.asf -c:v libxvid -q:v 4 -c:a libmp3lame -b:a 128k output.avi

This reads the source streams, encodes the video with Xvid, encodes audio as MP3 for broad AVI compatibility, and writes output.avi. The -q:v value controls Xvid quality in FFmpeg's quantizer scale; lower values generally produce higher quality and larger files. Try -q:v 3 for better quality or -q:v 5 for a smaller file.

To preserve the source frame rate and avoid unnecessary scaling, leave the video dimensions unspecified. If the target device requires a particular size, add an even-width and even-height scale, for example:

ffmpeg -i input.asf -vf scale=640:-2 -c:v libxvid -q:v 4 -c:a libmp3lame -b:a 128k output.avi

Check the available encoders with ffmpeg -encoders; the output must include libxvid. If the installed build lacks it, use a build compiled with Xvid support or select an Xvid video encoder in a desktop converter that supports AVI output. In a graphical application, choose the ASF file, set the output container to AVI, select Xvid or MPEG-4 Part 2 as the video codec, select MP3 audio, then start the conversion.

You can also convert the file for free on 101convert.com without installing software. Uploading may be unsuitable for confidential recordings, and browser-based conversion can be limited by file size or upload speed.

Quality, compatibility, and limitations

Conversion cannot restore detail already lost through ASF's original compression. Re-encoding the video introduces another generation of compression, so use the highest practical Xvid quality and avoid repeated conversions.

AVI/Xvid compatibility is usually best with MP3 audio, constant pixel dimensions, and standard progressive video. Older hardware may reject unusual frame rates, variable-frame-rate output, very high resolutions, or multiple audio and subtitle streams. ASF files protected by DRM may not decode unless the original authorized software can play them; conversion tools cannot legitimately bypass that protection.