Convert AAC to ADX
Max file size 100mb.
AAC vs ADX Format Comparison
| Aspect | AAC (Source Format) | ADX (Target Format) |
|---|---|---|
| Format Overview |
AAC
Advanced Audio Coding
Advanced Audio Coding (AAC) is a lossy audio codec standardized by ISO/IEC as part of MPEG-2 and MPEG-4 specifications. Developed as the successor to MP3, AAC delivers superior audio quality at equivalent bitrates through improved frequency resolution and more efficient coding of transient signals. It is the default audio format for Apple devices, YouTube, and most streaming platforms. Lossy Modern |
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 |
| Technical Specifications |
Sample Rates: 8 kHz – 96 kHz Bit Rates: 8–529 kbps (CBR/VBR) Channels: Up to 48 channels (7.1 surround common) Codec: AAC-LC, HE-AAC, HE-AAC v2 Container: ADTS (.aac), M4A (.m4a), MP4 (.mp4) |
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) |
| Audio Encoding |
AAC uses modified discrete cosine transform (MDCT) with psychoacoustic modeling for efficient lossy compression: # Encode to AAC at 256 kbps ffmpeg -i input.wav -codec:a aac \ -b:a 256k output.aac # High-quality AAC with FDK encoder ffmpeg -i input.wav -codec:a libfdk_aac \ -vbr 5 output.m4a |
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 |
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| Version History |
Introduced: 1997 (ISO/IEC 13818-7) Current Version: HE-AAC v2, xHE-AAC Status: Actively developed, industry standard Evolution: AAC-LC (1997) → HE-AAC (2003) → HE-AAC v2 (2006) → xHE-AAC (2012) |
Introduced: 1996 (CRI Middleware) Current Version: ADX2 (CRI ADX2/Atom) Status: Active in game industry, proprietary Evolution: ADX (1996) → ADX2 (2012, expanded codec support) |
| Software Support |
Media Players: VLC, iTunes, WMP, foobar2000, AIMP DAWs: Logic Pro, GarageBand, Adobe Audition Mobile: iOS, Android — native support Web Browsers: Chrome, Firefox, Safari, Edge Streaming: Apple Music, YouTube, Spotify, Tidal |
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 |
Why Convert AAC to ADX?
Converting AAC to ADX transforms standard audio into CRI Middleware's game-optimized ADPCM format, enabling integration with video game engines and interactive entertainment systems. ADX is the industry-standard audio format for game developers using CRI tools, supporting seamless looping and efficient real-time streaming on game consoles and PCs.
AAC is a lossy audio format used in music streaming on apple music, youtube, spotify. Converting to ADX re-encodes the audio using CRI's 4-bit ADPCM compression, which is specifically designed for video game audio playback. While this adds another lossy encoding step, the ADX format's game-specific features — seamless looping, real-time streaming, and ultra-low decode overhead — make it essential for game development workflows.
Game developers working with CRI Middleware tools such as CRI Atom Craft need audio assets in ADX format for integration into their game projects. The ADX format supports built-in loop point markers that enable seamless background music looping without audible gaps — a critical requirement for interactive entertainment. Converting AAC files to ADX is a necessary step in the game audio production pipeline for teams using the CRI toolchain.
When converting to ADX, be aware that the ADPCM encoding will reduce audio quality compared to the AAC source. For best results, start from the highest quality source available and let the ADX encoder handle the compression. The resulting file will be significantly smaller than the original, making it suitable for game disc storage and real-time streaming from game media.
Key Benefits of Converting AAC to ADX:
- Game Integration: Create audio assets compatible with CRI Middleware game engines
- Seamless Looping: Built-in loop point support for continuous background music
- Real-Time Streaming: Ultra-low decode overhead for smooth game audio playback
- Storage Efficiency: Significantly smaller files compared to uncompressed audio
- Console Compatibility: Proven format across PlayStation, Xbox, Nintendo, and PC platforms
- Proven Reliability: Used in thousands of commercial game titles (SEGA, Capcom, Konami)
- Modding Support: Replace or add custom audio in games using CRI ADX format
Practical Examples
Example 1: Game Development Audio Pipeline
Scenario: A game audio designer needs to convert background music tracks from AAC format to ADX for integration into a CRI Atom Craft project targeting PlayStation and Xbox platforms.
Source: level_bgm_forest.aac (5 min, 10 MB) Conversion: AAC to ADX (44.1 kHz, stereo, ADPCM) Result: level_bgm_forest.adx (5 min, ~1.5 MB) Game audio pipeline: 1. Compose and mix music in DAW, export as AAC 2. Convert AAC to ADX with loop point markers 3. Import ADX into CRI Atom Craft project 4. Set loop regions for seamless background playback 5. Build and deploy to target game platform
Example 2: Game Modding Community
Scenario: A modder wants to replace the soundtrack in a SEGA game with custom music. The game engine requires audio files in ADX format.
Source: custom_battle_theme.aac (3 min, 6 MB) Conversion: AAC to ADX Result: custom_battle_theme.adx (3 min, ~900 KB) Modding workflow: 1. Create or select replacement music track 2. Match original game audio specs (sample rate, channels) 3. Convert AAC to ADX format 4. Replace original ADX file in game data 5. Test in-game for proper playback and looping
Example 3: Retro Game Audio Recreation
Scenario: An indie developer is creating a game inspired by classic arcade titles and wants authentic-sounding audio using the ADX format for retro game feel.
Source: arcade_sfx_collection.aac (1 min, 2 MB) Conversion: AAC to ADX Result: arcade_sfx_collection.adx (1 min, ~300 KB) Retro audio benefits: - Authentic ADPCM compression character adds retro feel - Ultra-fast decoding perfect for rapid sound effect playback - Small file size ideal for numerous sound effects - Built-in looping for ambient audio and music - Compatible with both retro and modern game engines
Frequently Asked Questions (FAQ)
Q: Does converting AAC to ADX reduce audio quality?
A: Yes — ADX uses ADPCM lossy compression, so there will be some quality reduction compared to the AAC source. The ADX format prioritizes efficient real-time game audio playback over maximum fidelity. For game audio applications, this trade-off is acceptable since the compression artifacts are typically masked by gameplay sounds.
Q: What is ADX format and where is it used?
A: ADX (CRI ADX) is a proprietary audio codec by CRI Middleware, widely used in video games from publishers like SEGA, Capcom, Konami, and Bandai Namco. It supports ADPCM compression, seamless looping, and real-time streaming — features essential for interactive entertainment audio.
Q: Can I set loop points in the converted ADX file?
A: Loop point configuration is typically done in CRI Middleware tools like CRI Atom Craft after the basic ADX encoding. Our converter creates standard ADX files; for game-specific loop points, you will need to process the file further in CRI's development tools.
Q: What sample rate should I use for game audio in ADX format?
A: Most games use 44.1 kHz or 48 kHz for music and 22.05 kHz for sound effects and voice lines. Check the target game's audio specifications to match the expected sample rate. Using a higher sample rate than needed wastes storage and memory.
Q: Is ADX compatible with all game engines?
A: ADX is primarily supported through CRI Middleware integration. Games using CRI's audio tools (CRI Atom, CRI ADX2) natively support ADX. Other game engines like Unity and Unreal can use ADX via CRI plugins, but they also support standard formats like OGG and WAV natively.
Q: How much smaller will the ADX file be compared to AAC?
A: ADX's ADPCM encoding achieves roughly 4:1 compression compared to uncompressed PCM audio. Compared to AAC, the size reduction depends on the source format. A 50 MB WAV file would become approximately 12.5 MB as ADX, while a lossy source like MP3 might already be similar in size.
Q: Can I play ADX files on a normal media player?
A: Most standard media players do not support ADX natively. VLC can play ADX files, and foobar2000 supports them with the vgmstream plugin. For general listening, it is better to keep audio in standard formats and only convert to ADX when needed for game development.
Q: Can I batch convert multiple AAC files to ADX?
A: Yes — you can upload multiple AAC files to our converter and they will all be processed to ADX format. For large-scale game audio pipelines, FFmpeg scripting or CRI Middleware's batch processing tools are recommended.