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2010.03.16 22:34 "Re: TIFFVStripSize overflow, JPEG decoding", by Lee Cooper
Thank you Bob, Ed, for pointing out the limits on JPEG size. In light of this fact I think the file may be more complex than I expected. The example I listed is actually on the small side and I am certain that typical examples cannot be contained within the limits you mention. Looking at tiffdump output for a larger file (listed below) I see unlabeled tags with array values. I'm guessing these are pointers into multiple separate JPEGs. I cannot be sure however because the manufacturer's documentation is still not available. Supposing I have a pointer to a region of the file that contains an encoded JPEG, and the size of the region in bytes, is there a simple way to decode this region? ----------------------------------------------------------------------------------------------------------------------- Magic: 0x4949 <little-endian> Version: 0x2a Directory 0: offset 1750397507 (0x6854f243) next 1907037606 (0x71ab15a6) ImageWidth (256) LONG (4) 1<159744> ImageLength (257) LONG (4) 1<109824> BitsPerSample (258) SHORT (3) 3<8 8 8> Compression (259) SHORT (3) 1<7> Photometric (262) SHORT (3) 1<6> Make (271) ASCII (2) 10<Hamamatsu\0> Model (272) ASCII (2) 9<C9600-12\0> StripOffsets (273) LONG (4) 1<1542> SamplesPerPixel (277) SHORT (3) 1<3> RowsPerStrip (278) LONG (4) 1<109824> StripByteCounts (279) LONG (4) 1<1748254397> XResolution (282) RATIONAL (5) 1<44128> YResolution (283) RATIONAL (5) 1<43950> ResolutionUnit (296) SHORT (3) 1<3> Software (305) ASCII (2) 16<NDP.scan 2.2.60\0> DateTime (306) ASCII (2) 20<2010:03:05 11:48:44\0> YCbCrSubsampling (530) SHORT (3) 2<1 1> ReferenceBlackWhite (532) LONG (4) 6<0 255 128 255 128 255> 65420 (0xff8c) SHORT (3) 1<1> 65421 (0xff8d) FLOAT (11) 1<40> 65422 (0xff8e) SLONG (9) 1<5361304> 65423 (0xff8f) SLONG (9) 1<5804> 65424 (0xff90) SLONG (9) 1<0> 65425 (0xff91) LONG (4) 1<0> 65426 (0xff92) LONG (4) 535392<660 1814 3043 4100 5004 5909 6816 7961 9150 10304 11453 12588 13725 14867 16003 17146 18259 19393 20518 21623 22761 23871 24983 26154 ...> 65428 (0xff94) LONG (4) 1<398050858> 65433 (0xff99) LONG (4) 1<1500> 65439 (0xff9f) SLONG (9) 213<-8570480 12242718 -2 -10208955 12368932 -2 -8570480 12368932 -2 -7058043 12368932 11236400 -6932006 12242718 11239300 -7058043 12242718 11239100 -10334991 12242718 11232400 -10208955 12242718 11233400 ...> 65440 (0xffa0) SLONG (9) 142<0 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 1 8 1 9 1 10 1 11 ...> 65441 (0xffa1) LONG (4) 1<0> 65442 (0xffa2) ASCII (2) 9<C9600-12\0> 65443 (0xffa3) LONG (4) 1<0> 65444 (0xffa4) LONG (4) 1<80> 65445 (0xffa5) SLONG (9) 1<2> 65446 (0xffa6) SLONG (9) 1<0> >I forget the exact JPEG limit, but I see that these TIFFs are JPEG >compressed organized as strips and the strip width is close to the >JPEG limits. Perhaps this is where some overflow is happening (if it >is happening). > >Feel free to test with my free software (GraphicsMagick, >http://www.GraphicsMagick.org/) with logging enabled >(-debug coder,exception) since that helps to see many details. > >You forgot to tell us what operating system, compiler, and build >options that you used. Libtiff has certainly been used on files of >this size but perhaps there is something unusal about your files or >the build is defective. > >Bob >-- >Bob Friesenhahn >bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ >GraphicsMagick Maintainer, http://www.GraphicsMagick.org/