Free online USM to M4A converter

What the USM format is

USM is CRI Middleware's Sofdec media container, used mainly for game cutscenes. A file can contain interleaved video and audio streams, commonly CRI HCA or ADX audio, and may use encryption or game-specific metadata. You usually encounter USM files in extracted console or PC game data rather than in ordinary music libraries.

USM is not a standard audio format, and changing its filename extension to .m4a does not convert it. Many general media players and converters cannot read the container directly.

What the M4A format is

M4A is an audio-only MP4 file, usually containing AAC audio and sometimes Apple Lossless Audio Codec (ALAC). AAC-in-M4A provides broad support in phones, browsers, media players, and editing applications while generally producing smaller files than uncompressed WAV. M4A is suitable when the required result is the soundtrack rather than the original USM video.

How to actually convert USM to M4A

Use the built-in online converter

1. Open the USM-to-M4A converter on 101convert.com; it can be used free without installing software.
2. Upload the .usm file and select M4A as the output format.
3. Start the conversion and download the resulting file if the service can recognize the particular USM variant.

Encrypted or unusual game-specific USM files may not be accepted by an online converter. Do not upload copyrighted game assets unless you have permission to process them.

Use desktop tools when direct conversion fails

1. Open the USM with a CRI-aware extractor such as VGMToolbox or a compatible USM deinterleaving tool. Extract the audio stream instead of the video stream.
2. If the extractor produces an HCA file, decode it with a compatible vgmstream build, for example vgmstream-cli -o soundtrack.wav soundtrack.hca. If it produces ADX, use a CRI ADX decoder or an FFmpeg build that supports that ADX stream.
3. Encode the decoded WAV or other supported audio file as M4A with FFmpeg:
   ffmpeg -i soundtrack.wav -c:a aac -b:a 192k soundtrack.m4a

If FFmpeg directly recognizes the extracted source, the intermediate WAV can be skipped: ffmpeg -i soundtrack.hca -c:a aac -b:a 192k soundtrack.m4a. Direct HCA support depends on the FFmpeg build; decoding with vgmstream is generally the more reliable route.

For lossless output, use ffmpeg -i soundtrack.wav -c:a alac soundtrack.m4a. AAC is preferable for smaller files and wider compatibility.

Quality, compatibility, and limitations

The conversion can only preserve the audio stream that the USM extractor exposes. A USM may contain several language tracks, commentary, or channels; inspect each extracted stream and convert the required one. If the source audio is already lossy HCA or ADX, encoding it again as AAC introduces another lossy stage, so use a high enough bitrate such as 192–256 kbps for stereo music.

Some USM files are encrypted, split into companion files, or damaged. Those files may require the original game's decryption key or a game-specific extraction tool and cannot be converted by ordinary M4A software. M4A will contain audio only; it cannot preserve the USM cutscene video, subtitles, or game playback metadata.