2000.01.29 17:03 "G4 and DCT documentation [was: tiff2ps: G4 compression in PostScript]", by Tom Kacvinsky
Well, good luck finding out whether Adobe has determined it has to be "this way." If I am not mistaken, the problem with DCTDecode filter in Adobe CPSI is this (from GS's gsjmorec.h):
* Read "JPEG" files with up to 64 blocks/MCU for Adobe compatibility.
* Note that this #define will have no effect in pre-v6 IJG versions.
#define D_MAX_BLOCKS_IN_MCU 64
whereas the standard for blocks/MCU is lower (I think). As far as I know, this was (is) undocumented.
Tom Lane and/or L. Peter Deutsch can probably give more details to what I just wrote.