https://bugzilla.wikimedia.org/show_bug.cgi?id=72511
--- Comment #3 from Bawolff (Brian Wolff) <[email protected]> --- (In reply to Bawolff (Brian Wolff) from comment #2) > Ah, its related to the file having an invalid YCbCr sampling specification. > It specifies "2 3", and as far as I can tell, the valid choices are: To further that, the "2 3" would denote subsampling with 1/2 resolution in the horizontal direction, and 1/3 in the vertical resolution. When we ask image magick to scale it with say the -define 'jpeg:size=295x175' option, that hands off the initial scaling to libjpeg, which shrinks it by 50%. As a result it tries to in the vertical direction scale by 3/2 (Since it tries for every 2 vertical samples (from the scaling factor) to return 3 samples (from the subsampling)). But if -define 'jpeg:size=295x175' isn't there, then the full image is decompressed, and the vertical chroma is scaled by the integer 3. I don't know if this could be considered a bug in image magick, or if libjpeg should handle this better, or if the image is just broken. -- You are receiving this mail because: You are the assignee for the bug. You are on the CC list for the bug. _______________________________________________ Wikibugs-l mailing list [email protected] https://lists.wikimedia.org/mailman/listinfo/wikibugs-l
