jpeg codec

  • conexware

    Thread for Jpeg codec for advanced codec pack / .pa format.

    We already did our jpeg codec 6-7 years ago, maybe @eugene remembers what time exactly :). I believe our initial numbers were that it got compression gain of around 18% (vs 22%-24% of competition) but was 2x-3x faster than WinZip jpeg even in single thread state.

    So @eugene gene started rewriting it earlier this year. It will be fun to see what specs we end up with.

  • conexware

    maybe some @Alpha-Testers will chime in about their jpeg codec expectations :-)

  • Is it re-compressing or “just” a codec optimized to compress JPEG data further down (lossless)?

  • conexware

    Many popular formats (.jpg,.pdf,.docx) use outdated methods of data compression.
    So it started making sense to remove that outdated compression and apply better one.
    Then do it backwards to restore the file.
    It usually only makes sense to do it losslessly, because it is impossible to automate otherwise -
    some other file always can contain a hash of this one, or something.
    And that’s what we call “recompression”, while lossy transformation would be called “re-encoding”.

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