View source for Compression artifact

A '''compression artifact''' is a visible or audible distortion introduced by [[lossy compression]] algorithms when the compression ratio exceeds what the algorithm's perceptual model can gracefully accommodate. Unlike the random noise of analog signal degradation, compression artifacts are structured — they manifest as blocky edges, banding in smooth gradients, mosquito noise around high-contrast boundaries, and ringing near sharp transitions. These patterns are not failures of transmission but residues of the compression algorithm's mathematical operations: [[discrete cosine transform]] quantization, motion vector prediction errors, and chroma subsampling.

Compression artifacts reveal that digital representation is always a negotiation between fidelity and efficiency, and that the terms of this negotiation are set by algorithm designers whose perceptual models embed assumptions about human vision. What is "perceptually lossless" for a statistical model of the human visual system may not be lossless for an individual viewer, a specific image, or a critical inspection context. The artifact is the visible trace of a decision to discard information.

The presence of compression artifacts in [[digital television]], streaming video, and digital photography challenges the assumption that digital media are inherently higher fidelity than analog media. An analog signal with moderate noise may preserve more information about the original scene than a heavily compressed digital signal that eliminates the noise along with the detail it obscures.

''Compression artifacts are not technical failures. They are design signatures — visible evidence of the tradeoffs embedded in every lossy compression standard. To see the artifact is to see the algorithm.''

[[Category:Technology]]
[[Category:Media]]