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TIFF and LibTiff Mail List Archive

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

2010.05.11 16:02 "Re: [Tiff] Tiff with varying bit depths", by Thomas Richter

Frank Warmerdam schrieb:

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

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?

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

Do I misunderstand this? The file isn't tiled, but striped, thus why would TIFFReadRawTile() help?

Anyhow, I don't even get that far, the code already fails at TIFFOpen():

 tfd = TIFFOpen(basename,"r");
    if (tfd == NULL)
      PostError("failed to open the TIFF file %s\n",basename); // <---
goes here immediately.

(From my code).

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.

That's what I would basically need. The file is uncompressed, i.e. the data is in a single stripe, bit-packed as five bits red, six bits green, five bits blue. I assume this is tiff-conforming, but please look into the file yourself.

Can you make one of these files available?

Certainly, please find it attached.

Note that this was created by a custom tiff writer. I *assume* its the proper way of creating such a tiff file, but I don't know. Would be great if you could look into this.

Thanks,
Thomas