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#13 cjpeg -sample 4x2 -> color havoc in JPEGsnoop

closed-fixed
nobody
None
5
2012-11-04
2012-04-16
Frédéric Kayser
No

Hello,
I'm exploring the limits of chorma subsampling and it appears that JPEGsnoop does not handle it, files produced by:
cjpeg -optimize -quality 90 -sample 4x2 (that's eight Y' samples for one Cr Cb sample 4:1:0) really looks bad in JPEGsnoop.

The small attached sample file becomes pink, whereas it should have a white background (ok in other decoders).

Discussion

  • Frédéric Kayser

    Frédéric Kayser - 2012-04-16

    Black text on white backroud, gets pink in JPEGsnoop.

     
    Thumbnail
    kiwi.jpg

  • Frédéric Kayser

    Frédéric Kayser - 2012-04-16
    • summary: cjpeg -sample 4x2 -> color havoc in JPEGFsnoop --> cjpeg -sample 4x2 -> color havoc in JPEGsnoop
     

  • Calvin Hass

    Calvin Hass - 2012-04-25

    There was a limitation in the code that limited chroma subsampling to a maximum of 2x2. The sample was 4x2, which would have triggered an exception in the debug build only.

    Issue is now fixed in local code and undergoing testing before release.

     

  • Calvin Hass

    Calvin Hass - 2012-04-25
    • status: open --> pending
     

  • Calvin Hass

    Calvin Hass - 2012-04-25
    • status: pending --> open
     

  • Calvin Hass

    Calvin Hass - 2012-11-04
    • status: open --> closed-fixed
     

  • Calvin Hass

    Calvin Hass - 2012-11-04

    Fixed in version 1.6.0

     

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