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May 2010

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2010.05.11 15:32 "Tiff with varying bit depths", by Thomas Richter
2010.05.11 15:49 "Re: Tiff with varying bit depths", by Frank Warmerdam
2010.05.11 16:02 "Re: Tiff with varying bit depths", by Thomas Richter
2010.05.11 16:31 "Re: Tiff with varying bit depths", by Scott Ribe
2010.05.11 16:52 "Re: Tiff with varying bit depths", by Igor Skochinsky
2010.05.11 16:58 "Re: Tiff with varying bit depths", by Scott Ribe
2010.05.11 19:19 "Re: Tiff with varying bit depths", by Thomas Richter
2010.05.11 15:58 "Re: Tiff with varying bit depths", by Bob Friesenhahn
2010.05.11 20:16 "Re: Tiff with varying bit depths", by Joris Van Damme
2010.05.11 20:22 "Re: Tiff with varying bit depths", by Thomas Richter
2010.05.11 21:33 "Re: Tiff with varying bit depths", by Joris Van Damme

2010.05.11 15:49 "Re: Tiff with varying bit depths", by Frank Warmerdam

Thomas Richter wrote:
> Hi folks,
> 
> I currently have a need to read and write TIFF files with a varying bit 
> depth. To be specific, this is a BGR565 image packed into TIFF:
> 
> $ tiffdump out.tif
> out.tif:
> Magic: 0x4949 <little-endian> Version: 0x2a
> Directory 0: offset 8 (0x8) next 0 (0)
> ImageWidth (256) LONG (4) 1<64>
> ImageLength (257) LONG (4) 1<64>
> BitsPerSample (258) SHORT (3) 3<5 6 5>
> Compression (259) SHORT (3) 1<1>
> Photometric (262) SHORT (3) 1<2>
> StripOffsets (273) LONG (4) 1<140>
> SamplesPerPixel (277) SHORT (3) 1<3>
> RowsPerStrip (278) LONG (4) 1<64>
> StripByteCounts (279) LONG (4) 1<8192>
> SampleFormat (339) SHORT (3) 1<1>
> 
> 
> Obviously, the library does not support this, but what are my options if 
> I need to read this file? I'm not too keen to write a tiff-parser
> myself, unless I really really have to - and - I afraid - I really 
> really have to read this file in one way or another.
> 
> Is there a way to get at least hands on the raw stripe data without the 
> lib falling over? Failing that, what is the patch acceptance policy
> for libTIFF? Would you accept a patch that adds support for this, 
> probably in a limited way?

Thomas,

Have you investigated using TIFFReadRawTile() to read these tiles?   At
what point does libtiff fail with this file?

I don't anticipate the regular decompression/decoding logic working with
such a file in the near future, but I would like to see it be possible
to fetch the raw tile/strip data without too much difficulty.

Can you make one of these files available?

Best regards,
-- 
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