definition v2 of audio-compression

Audio compression is a human-made codec technique that reduces the size of audio data while preserving acceptable playback quality, typically via perceptual encoding, lossless encoding, or lossy transform coding. Parameters: codec family (e.g., MP3, AAC, Opus, FLAC), bitrate or quality setting, encoding mode (constant/variable bitrate), psychoacoustic model parameters, and container format. Mechanism: the audio signal is analyzed spectrally, perceptual masking thresholds are estimated, and quantization plus entropy coding discard information deemed inaudible, producing a smaller bitstream that can be decoded back to audio. Persistence: implemented in software encoders/decoders, streaming services, broadcast chains, and standardized specifications (ISO/IEC, ITU). [formal: compressio-audio | substrate: matter | horizon: a moment | explicit: yes | epoch: 0.01]