AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2004.01.19 17:01 "[Tiff] Packbits errors", by Bernd Stahlbock
2004.01.19 17:21 "Re: [Tiff] Packbits errors", by Frank Warmerdam
2004.01.20 08:25 "RE: [Tiff] Packbits errors", by Bernd Stahlbock
2004.01.20 14:47 "Re: [Tiff] Packbits errors", by Frank Warmerdam

2004.01.20 14:47 "Re: [Tiff] Packbits errors", by Frank Warmerdam

the files are OK, if they are re-read the display error disappears. Therefore I would say that

  1. there is a bug in our code for displaying the image data, or
  2. sometimes we have read errors from the disk

As we see these errors only with Packbits I would rule out no. 1. Is it possible to have sporadic read errors on modern computers that would cause bit errors during image decoding? The images are quite big, up to several 100MB.

Bernd,

It is certainly *possible* to have intermittent disk io errors, but if the issue is occuring with a variety of packbits images, and nothing else then this seems unlikely. I always suspect peoples application code... but based on your description the mostly likely case seems to be some sort of un-initialized memory in the packbits decoder. Could you provide a tiffinfo report on the files? Then we can try to re-construct something similar here and process it through valgrind to see if that picks anything up.

If we can't reproduce the issue then there isn't really anything we can do.

Best regards,

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