Lossy compression is a data encoding method that reduces file size by permanently eliminating certain information — discarding perceptually or statistically redundant data so the decoded output is an approximation of the original, not a bit-for-bit replica. Parameters: (1) a compression ratio that trades fidelity for size; (2) a distortion metric measuring the difference between original and decoded; (3) a codec implementing the specific discarding strategy (quantization, transform coding, subband splitting). Persistence: encoded in file formats, algorithms, and standards that persist through specification documents and software implementations. [formal: compressio_lossiva | substrate: matter | horizon: hours | explicit: yes | epoch: 0.01]
Accepted ontology entry
lossy-compression
Lossy compression is a data encoding method that reduces file size by permanently eliminating certain information — discarding perceptually or statistically redundant data so the decoded output is an approximation of the original, not a bi…
Definition
Why it is in scope
Lossy compression is a human-made data encoding method that reduces file size by permanently eliminating redundant or less-important information, accepting some loss of fidelity in exchange for significantly smaller output. It is built to persist through standardized algorithms (JPEG, MP3, MPEG) that define what information is preserved and what is discarded.
Names and aliases
- lossy-compressionen · CANONICAL
Relations from this entry
- cmrs990nt00goollh7iroikawINSTANCE_OF →
lossy-compression IS a specific kind of compression. Per Law 9: a competent speaker would call lossy-compression 'a kind of compression' — it compresses by discarding data, distinguishing it from lossless compression. The nearest accepted kind is 'compression' itself.
- cmsftujnv00f0qszgpolboiajDERIVED_FROM →
Information theory (Shannon, 1948) existed first and conceptually fed into lossy compression. Rate-distortion theory — the mathematical foundation of lossy compression — is a direct result of information theory. Which-came-first: information theory first, lossy compression is the applied construct.
Relations to this entry
- post-echo← DEPENDS_ON
Post-echo (as defined in its entry) is a temporal artifact arising from windowing in transform-domain lossy compression (e.g. MP3). Remove lossy-compression and the specific mechanism that produces this artifact no longer operates. The dependency is object-level: without the lossy-compression pipeline, post-echo cannot occur.
Record identity
- Created
- Aug 10, 2026, 6:30 PM UTC
- Content hash
- f26c85bfe77cfd139c681cd5a2e7d6fe7c173437e905306908447fa839ab5ce5