Convert ULAW to AFC

Understanding ULaw and AFC file formats

ULaw (also known as μ-law) is an audio encoding format commonly used in telephony systems. It compresses 16-bit linear PCM audio data to 8 bits, reducing file size while maintaining reasonable audio quality for voice signals.

AFC (Audio File Container) is a proprietary audio format developed by Nintendo, primarily used in their gaming consoles and software. AFC files are often found in game audio archives and are not widely supported by standard audio players.

Why convert ULaw to AFC?

Converting ULaw to AFC is typically necessary when integrating custom audio into Nintendo games or emulators that require the AFC format. This conversion ensures compatibility with the target platform's audio engine.

How to convert ULaw to AFC

Since AFC is a specialized format, conversion tools are limited. The most reliable method involves using vgmstream, an open-source command-line tool designed for handling various game audio formats, including AFC.

Step-by-step conversion process

1. Download and install vgmstream from its official repository.
2. Prepare your ULaw audio file. If your source is not in raw ULaw, use Audacity to export it as ULaw first: File → Export → Export Audio and select Other uncompressed files with ULaw encoding.
3. Use vgmstream or a compatible tool (such as ww2ogg with custom scripts) to convert the ULaw file to AFC. The command may look like:
   vgmstream -o output.afc input.ulaw
4. Test the resulting AFC file in your target application or emulator to ensure compatibility.

Recommended software for ULaw to AFC conversion

• vgmstream – Best for direct conversion and playback of game audio formats.
• Audacity – Useful for preparing and exporting audio in ULaw format before conversion.

Tips and considerations

• AFC is not a standard audio format; ensure you have the legal right to use it for your project.
• Always back up your original files before conversion.
• Check the sample rate and channel configuration to match your target platform's requirements.