Convert ADX to AU
Max file size 100mb.
ADX vs AU Format Comparison
| Aspect | ADX (Source Format) | AU (Target Format) |
|---|---|---|
| Format Overview |
ADX
CRI ADX (ADPCM)
CRI ADX is a proprietary lossy audio codec developed by CRI Middleware for use in video games. Based on ADPCM (Adaptive Differential Pulse-Code Modulation), ADX provides efficient compression optimized for real-time game audio playback. Widely used by SEGA, Capcom, Konami, and Bandai Namco, ADX supports seamless looping and streaming — critical features for interactive entertainment audio. Lossy Legacy |
AU
Sun/NeXT Audio
AU (Audio) is an audio file format originally developed by Sun Microsystems for Unix/NeXT systems. AU files typically contain PCM, mu-law, or A-law encoded audio data with a simple header structure. While largely superseded by WAV and AIFF in modern workflows, AU remains relevant in Unix/Linux audio pipelines and legacy system integration. Lossless Legacy |
| Technical Specifications |
Sample Rates: 22.05 kHz, 44.1 kHz, 48 kHz Bit Rates: Variable, typically 40–160 kbps Channels: Mono, Stereo Codec: CRI ADPCM (4-bit) Container: ADX (.adx) |
Sample Rates: 8 kHz – 48 kHz (commonly 8 kHz) Bit Depth: 8, 16, 24, 32-bit (PCM); 8-bit (mu-law/A-law) Channels: Mono, Stereo Codec: PCM, mu-law, A-law, ADPCM Container: AU/SND (.au, .snd) |
| Audio Encoding |
ADX uses 4-bit ADPCM encoding, predicting each sample from previous values and storing only the difference, achieving roughly 4:1 compression: # Encode WAV to ADX ffmpeg -i input.wav -codec:a adpcm_adx \ output.adx # Specify sample rate ffmpeg -i input.wav -codec:a adpcm_adx \ -ar 44100 output.adx |
AU files use a simple header followed by raw audio data, commonly mu-law encoded for telephony: # Encode to AU (mu-law) ffmpeg -i input.wav -codec:a pcm_mulaw \ -ar 8000 -ac 1 output.au # AU with PCM 16-bit ffmpeg -i input.wav -codec:a pcm_s16be \ -ar 44100 output.au |
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| Version History |
Introduced: 1996 (CRI Middleware) Current Version: ADX2 (CRI ADX2/Atom) Status: Active in game industry, proprietary Evolution: ADX (1996) → ADX2 (2012, expanded codec support) |
Introduced: 1980s (Sun Microsystems) Current Version: AU/SND format Status: Legacy, still supported in Unix ecosystems Evolution: NeXT/Sun AU (1980s) — stable format, no major revisions |
| Software Support |
Game Engines: CRI ADX2, Unreal Engine (via plugin), Unity (via plugin) Media Players: VLC, foobar2000 (with vgmstream plugin) Converters: FFmpeg, vgmstream, CRI tools Platforms: PlayStation, Xbox, Nintendo, PC, Dreamcast, Saturn Development: CRI Atom Craft, CRI Sofdec SDK |
Media Players: VLC, Audacity, Sox Systems: Unix, Linux, Solaris native DAWs: Audacity, Sox, Adobe Audition Programming: Java Sound API, Python wave module Converters: FFmpeg, Sox, Audacity |
Why Convert ADX to AU?
Converting ADX to AU transforms game-specific ADPCM audio into a widely compatible format suitable for everyday listening, editing, and professional workflows. ADX files are designed for video game audio playback with features like seamless looping and real-time streaming, but they are not supported by standard media players or audio editing software. By converting to AU, you unlock the ability to play, edit, and share your audio across any platform.
ADX uses 4-bit ADPCM lossy compression optimized for game consoles, which sacrifices some audio fidelity for efficient real-time decoding. AU provides a lossless container that preserves the decoded audio without any further quality loss. While the original ADPCM compression artifacts remain, converting to AU ensures no additional degradation occurs during subsequent editing or format conversion operations.
Game audio enthusiasts and modding communities frequently need to extract music and sound effects from games that use CRI Middleware's ADX format. Whether you are creating a soundtrack compilation from SEGA or Capcom titles, preparing game audio for a remix project, or simply want to listen to your favorite game music on a standard audio player, converting ADX to AU bridges the gap between proprietary game audio and universal media playback.
Keep in mind that ADX audio was originally compressed with ADPCM for game use, so the converted AU file will reflect the quality of the ADX source rather than studio-original quality. For archival purposes, it is best to convert at the source sample rate (typically 44.1 or 48 kHz) to avoid unnecessary resampling. The conversion process is fast since ADX decoding requires minimal CPU processing.
Key Benefits of Converting ADX to AU:
- Universal Playback: Play game audio on any media player and device
- Editing Capability: Edit and mix extracted game audio in any DAW
- Format Compatibility: Access AU's wide ecosystem of tools and hardware
- Sharing Made Easy: Distribute game music in a universally recognized format
- Quality Preservation: Maintain maximum quality from the decoded ADX source
- Metadata Support: Add tags, album art, and track information to the converted files
- Production Workflow: Use game audio as source material for remixes and compositions
Practical Examples
Example 1: Extracting Game Soundtrack for Personal Listening
Scenario: A gamer wants to listen to the soundtrack from a SEGA Dreamcast game that stores its music as ADX files. They need to convert the extracted audio to AU for playback on their phone and computer.
Source: stage_theme_01.adx (4 min, 44.1 kHz, stereo, 1.2 MB) Conversion: ADX to AU Result: stage_theme_01.au (40 MB) Workflow: 1. Extract ADX files from game data using vgmstream 2. Convert ADX to AU for standard playback 3. Add metadata tags (track title, game name, composer) 4. Import into music library for everyday listening 5. Create playlist of favorite game tracks
Example 2: Game Audio Remix and Music Production
Scenario: A music producer wants to sample and remix audio from classic Capcom fighting games stored in ADX format. They need high-quality decoded audio for their DAW project.
Source: character_theme.adx (2 min, 44.1 kHz, stereo, 640 KB) Conversion: ADX to AU Result: character_theme.au (20 MB) Benefits: - Decoded audio ready for DAW import and sampling - No proprietary game audio plugins required - Compatible with Ableton, FL Studio, Logic Pro - Can apply effects, time-stretch, and pitch-shift freely - Clean source for remix production workflow
Example 3: Game Preservation and Archival
Scenario: An archivist is preserving audio from retro console games and needs to convert ADX files to a long-term storage format that is widely supported and well-documented.
Source: boss_battle_music.adx (6 min, 44.1 kHz, stereo, 1.8 MB) Conversion: ADX to AU Result: boss_battle_music.au (60 MB) Archival considerations: - Widely supported format for long-term preservation - Decoded from proprietary format to open standard - Original ADX loop points documented in metadata notes - Compatible with digital preservation repositories - Ensures accessibility for future playback systems
Frequently Asked Questions (FAQ)
Q: Does converting ADX to AU improve audio quality?
A: No — the conversion decodes the ADX ADPCM audio and re-encodes it as AU. The resulting quality is limited by the original ADX compression. However, converting to AU gives you access to better playback support, editing tools, and metadata features that ADX lacks.
Q: What is the ADX format used for?
A: ADX (CRI ADX) is a proprietary audio codec by CRI Middleware used primarily in video games. It features ADPCM-based lossy compression, built-in loop points, and real-time streaming capabilities. SEGA, Capcom, Konami, and Bandai Namco games commonly use ADX for music and sound effects.
Q: Can I preserve loop points when converting ADX to AU?
A: Standard audio formats like AU do not natively support ADX's loop point markers. The loop information is lost during conversion. If you need loop functionality, document the loop start and end sample positions before converting, and implement looping in your playback application or DAW.
Q: How do I extract ADX files from game data?
A: Tools like vgmstream, CRI File System tools, and QuickBMS can extract ADX audio from game archives. Once extracted, use FFmpeg or our converter to transform ADX files to AU or other standard formats for playback.
Q: What sample rate should I use for the converted AU file?
A: Use the same sample rate as the original ADX file (typically 44.1 kHz or 48 kHz) to avoid unnecessary resampling artifacts. Upsampling an ADX file to a higher rate does not improve quality — it only increases file size.
Q: Is there any quality difference between different ADX files?
A: Yes — ADX files can vary in quality depending on the sample rate, number of channels, and the encoding settings chosen by the game developer. Higher-budget games often use higher quality ADX encoding. The bit rate typically ranges from 40 to 160 kbps.
Q: Can I batch convert multiple ADX files to AU?
A: Yes — you can upload multiple ADX files to our converter and they will all be processed and converted to AU. For command-line batch conversion, FFmpeg can process entire directories of ADX files using scripting.
Q: Will the converted file work on my mobile device?
A: AU is widely supported on modern smartphones and tablets, so the converted file should play without issues on iOS and Android devices. The original ADX format is not supported by standard mobile media players, making conversion necessary for mobile playback.