concept

Lossy compression

Compression that permanently discards detail to reach much smaller files.

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Lossy compression explained

Lossy encoders model human perception. Image codecs discard high-frequency detail and colour precision; audio codecs drop frequencies masked by louder neighbours. What is removed cannot be recovered.

Quality is a dial, not a fixed property. A JPEG saved at quality 90 is close to indistinguishable from the original; the same photo at quality 40 shows blocking around edges.

Repeatedly re-encoding a lossy file causes generation loss: each pass compresses artefacts introduced by the previous one. Keep a lossless master and export lossy copies from it.

Where you meet it

  • JPEG photographs
  • MP3 and AAC audio
  • H.264 video
  • WebP in lossy mode

Lossy compression scores

Deterministic scores calculated from the structured facts above. Identical facts always produce identical scores.

Overall score

100/100

  • Archiving score

    100
    • it is a current, actively maintained format
    • it is actively maintained and current

    Confidence 33% · evidence coverage 56%

  • Longevity score

    100
    • it is actively maintained and current
    • it is a current, actively maintained format
    • it sits at the centre of the format ecosystem, with many documented relationships

    Confidence 35% · evidence coverage 75%

Frequently asked questions

Can I convert a lossy file back to lossless quality?

No. Converting a JPEG to PNG preserves the JPEG's current pixels but cannot restore the detail the JPEG encoder discarded.

Data quality

Every claim on this page is classified as a verified fact, a derived fact or an assumption.

Overall confidence
85%
Verification status
verified
Last reviewed
2026-08-03
Verified facts
1

1 classified claim backed by 1 source.

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Sources and review status

Review status: verified · confidence 85%

Last reviewed 2026-08-03 (revision 1).

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