2008.10.23 19:56 "Re: [Tiff] JPEGSetupEncode messages", by Jeffrey Ratcliffe

2008/10/23 Gerben Vos <Gerben@zylab.com>:

JPEGSetupEncode: RowsPerStrip must be multiple of 8 for JPEG

Add the "-r 8" option to tiffcp. Or 16, or 24, or...

JPEGSetupEncode: BitsPerSample 16 not allowed for JPEG

Reduce it to 8 bits (or compile a 12 bits version of libjpeg and link it to libtiff, then reduce your image to 12 bits and rest assured in the knowledge that almost no-one will be able to decode it).

Thanks for this, and all the other help. I now have things working for this one case, which leads me to more questions:

Is there any way of telling at runtime from the command line (or with perlmagick) whether libjpeg is compiled for 8 or 12 bit? Or can I safely assume that it is 8 bit?

Presumably this is 8 bits per channel, so for 3 channels, 24 bits?

Sometimes RowsPerStrip must be a multiple of 8 for JPEG, and sometimes 16. How can I tell which will be necessary?

Regards

Jeff