Free online XWM to AAC converter

What the XWM format is

XWM is a game-audio format based on Microsoft’s xWMA audio technology. Bethesda titles such as The Elder Scrolls V: Skyrim and Fallout games store some voice, music, and sound-effect assets as XWM files, often inside or alongside extracted game archives.

The format is intended for game engines rather than general-purpose media software. Its contents may use WMA-family compression and can include channel and sample-rate information that must be preserved during decoding. The .xwm extension is therefore not the same as a normal WMA file renamed by the user.

What the AAC format is

AAC is a lossy audio codec supported by smartphones, browsers, streaming platforms, media players, and most modern editing applications. It usually appears as a raw .aac stream or inside an MPEG-4 container such as .m4a.

AAC generally provides better quality than MP3 at the same bitrate and supports common game-audio properties such as stereo sound and standard sample rates. Use an .m4a output when metadata and broad player compatibility matter; use raw .aac when a program specifically requires an AAC elementary stream.

How to actually convert XWM to AAC

Using the 101convert online converter

1. Open the XWM-to-AAC converter on 101convert.com.
2. Choose or drop the .xwm file.
3. Select AAC as the output format and start the conversion.
4. Download the resulting .aac file, or select an M4A/AAC option if the destination application accepts MPEG-4 audio.

This option requires no installed conversion software. Do not upload copyrighted game assets unless your use complies with the game’s license and applicable law.

Using FFmpeg on a desktop

Recent FFmpeg builds may decode XWM directly. Test the input first with:

ffmpeg -i input.xwm

If FFmpeg recognizes the stream, create an AAC file with:

ffmpeg -i input.xwm -c:a aac -b:a 192k output.aac

For an MPEG-4 container, which is usually easier for players and editors to handle, use:

ffmpeg -i input.xwm -c:a aac -b:a 192k output.m4a

If FFmpeg reports an unknown format or cannot decode the stream, first decode the XWM file with a Bethesda-compatible XWM decoder such as the xWMAEncode utility or a maintained XWM conversion tool, then encode the resulting WAV file:

ffmpeg -i decoded.wav -c:a aac -b:a 192k output.m4a

Use a separate output filename for every source file; batch scripts that overwrite files can destroy the original decoded audio.

Quality and compatibility limits

XWM is normally already compressed, so converting it to AAC is a lossy-to-lossy transcode. The AAC bitrate cannot restore detail discarded during the original XWM encoding. For preservation or later editing, decode to WAV first and keep that uncompressed intermediate; use AAC only for playback or distribution.

A bitrate of 128–192 kbps is normally sufficient for stereo game audio, while 256 kbps reduces additional AAC artifacts at the cost of larger files. Do not force stereo or change the sample rate unless the destination requires it; retain the source channel layout and sample rate to avoid unnecessary resampling.

Some XWM files use codecs or headers that general media converters do not support. A failed direct conversion does not necessarily indicate damaged audio; it may require a Bethesda-specific decoder. Files extracted from encrypted, modified, or incomplete game archives may also be unusable until the original archive is correctly unpacked.