ADC (Adaptive Differential Coding) . Lossy Audio Codec and more.

ADC – Audio Codec for lossy Compression - 

Description:
ADC (Adaptive Differential Codec) is a custom-developed audio compression algorithm designed to achieve exact byte-for-byte preservation when encoding and decoding under fixed parameters. It enables perfect regeneration of the original waveform across multiple generations of recompression, provided the same encoding setting is used.  Unlike traditional lossy codecs, ADC supports both hybrid and deterministic modes, allowing precise audio editing and long-term archival. This feature is particularly useful for educational recordings, archival work, or session-based editing, where concatenated streams retain bit-exact fidelity without re-encoding distortion. This release includes documentation, reference test files, and specification of the codec’s design rationale. The implementation is currently distributed under a custom closed-source license for demonstration and academic review only.

Unique Features of ADC (Adaptive Differential Coding)

• Generational Stability: ADC is a lossy codec that maintains perfect bitwise integrity between generations. Each recompression of an ADC file (even with different encoding profiles) yields an identical result with no quality degradation over time.

• Lossless Equivalence (Pseudo-Lossless): Output files decoded from ADC can reconstruct the original compressed file, as long as the same compression parameters (keys) are maintained during recompression. This behavior enables "lossless-like" workflows even in a lossy context.

• Compression Efficiency: Achieves up to 5:1 compression ratios (PEAQ results  ideal for high-fidelity archiving).

• Generational Editing: ADC allows seamless editing, cutting, and reassembly of portions of an audio stream without introducing cumulative errors or cascading degradation typical of other lossy formats.

• Reconstructability: Compressed ADC files can be regenerated from their decoded PCM output using the same keys, even after the original compressed version has been lost.

Usage: 

ADC <command> -<switch ..>  inputfile  outputfile
<Commands>
 c               compress WAV to ADC
 d               extract  ADC to WAV
 p               extract  ADC to WAV and play sound

<Switches>
 -b[n]        set CBR of ADC file compression in kb/s -q128(low)....-q320 (high)
 -q[n]        [default -q32] set bits of ADC file -q20(low)  ....  -q511  (high)
 -t[n]        [default -t0]  set time of ADC file -t0(low)   ....    -tx  (high)
 -h           [default  no]  high quality (better compression ratio, but slower)

Note: 

To get the exact match you should not activate the "-h" option which creates another lossy version.

The -bx option where x is the desired bitrate combined with the -h option until proven otherwise retains the second generation lossless reconstruction feature.

mail: miadebora@homail.it