Advanced Domain Compressor (ADC) v.085 rev.0

Redefining the DNA of Time-Domain Audio Compression

The Paradigm Shift

While the industry has long relied on frequency-domain processing (MDCT-based codecs like AAC or LC3) for its undeniable efficiency, it has often come at the cost of temporal smear and pre-echo artifacts. ADC is a next-generation audio codec engineered to challenge this convention. By evolving the principles of time-domain compression, ADC introduces a sophisticated 8-band filter bank architecture and state-of-the-art entropy coding, delivering a quantum leap in coding gain and perceptual transparency.

Core Architecture: The Time-Domain Advantage

Unlike traditional codecs that map signals into the frequency domain, ADC operates directly on the raw audio waveform. By capitalizing on deep temporal correlations, ADC achieves:

·       Ultra-Low Latency: Critical for real-time applications.

·       Transient Integrity: Total immunity to the pre-echo and "smearing" typical of block-based transforms.

·       High-Granularity Division: Our new 8-band filter bank doubles the granularity of previous versions, allowing for surgical noise-floor distribution across the spectrum without leaving the time domain.

Technical Deep Dive: Contextual Coding & Logic

The true power of ADC lies in its Advanced Contextual Coding. This scheme exploits statistical dependencies between successive samples and across the eight subbands, drastically reducing residual energy.

·       Evolved Range Coding: Predictive residuals are processed through a high-performance Range Coding engine, achieving near-optimal compression ratios even at aggressive bitrates.

·       The "q" Command Reintroduced: By popular demand, we have re-integrated the "q" parameter. This allows users to set a static quality factor, providing granular control over the compression ratio for those who require a fixed fidelity target.

·       Perceptual Optimization: Moving beyond simple "Perfect Reconstruction," ADC now prioritizes Psychoacoustic Efficiency. By strategically shaping noise, we’ve traded mathematical identity for a massive leap in perceived audio "air" and transparency.

Ready for the Modern Era: Streaming & Playback

ADC has evolved from a technical breakthrough into a production-ready codec ecosystem. It is no longer just an encoder; it is a complete solution for the modern web and broadcast landscape.

·       Integrated Internal Player: ADC now features a native, high-performance internal player, allowing for seamless previewing and deployment without third-party dependencies.

·       Streaming-Ready: With its ultra-low overhead and robust error resilience, ADC is fully optimized for real-time streaming environments.

·       Native Joint Stereo: Optimized for spatial efficiency and modern stereo imaging.

Flexible Rate Control: Precision vs. Economy

·       Optimal VBR (Variable Bitrate): The native heart of ADC. It dynamically allocates bits based on the complexity of the 8 subbands, ensuring consistent quality at the lowest possible footprint.

·       Standard CBR (Constant Bitrate): For fixed-bandwidth applications, ADC provides rock-solid reliability, though we recommend VBR for users seeking the highest efficiency gains.

The Challenge: A New Standard

Frequency-domain codecs have served us well for decades, but they are reaching their theoretical limits. ADC represents a bold bet on the future of audio. By proving that time-domain processing can match—and exceed—the efficiency of the "old guard," we are opening a new chapter in audio fidelity.

ADC isn't just a codec; it’s a promise of crisper transients, lower latency, and a more natural listening experience.

USAGE:

  Compression:   adc.exe c [options] <input.wav> <output.adc>
  Decompression: adc.exe d <input.adc> <output.wav>
  Direct Play:   adc.exe p <input.adc> [output.wav]
  Streaming:     adc.exe s <input.adc> [seek_seconds]

Options per compressione:
  -q<factor>   Set factor fixed , best quality
  -v<bitrate>  Set VBR bitrate (64-320 kbps) default 128 kbps
  -b<bitrate>  Set CBR bitrate (64-320 kbps)
  -j           Enable Joint Stereo
  -h           High Quality mode

Examples:
  adc.exe c -v128 -j input.wav output.adc
  adc.exe d input.adc output.wav
  adc.exe p input.adc
  adc.exe s input.adc

home:  http://heartofcomp.altervista.org/ADCodec.htm

discussion: https://encode.su/threads/4291-ADC-(Adaptive-Differential-Coding)-My-Experimental-Lossy-Audio-Codec

contact mail: miadebora@homail.it