2004.01.19 17:21 "Re: [Tiff] Packbits errors", by Frank Warmerdam

I have some rare reading errors with packbit compressed files. I get no error message, but the images have some small image corruptions where pixels are shifted to the right a little bit. Sometimes only one line, sometimes maybe 300 or more. The next time I read the image, the display is without errors.

Are there any known errors like this for packbits? Doesn't have packbits an error correction?

Bernd,

Packbits does not include any error correction, but if the data is corrupted in some way you should get the same results each time. If you have a file demonstrating this problem file the bug in bugzilla and Andrey can try and reproduce it. He could also run it through valgrind which may ferret out subtle memory initialization bugs.

I would note the packbits decoder is really quite simple, and it is surprising there would be a bug in it after all these years.

Best regards,

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