LibTiff Mailing List
TIFF and LibTiff Mailing List Archive
October 2000
Previous Thread
Next Thread
Previous by Thread
Next by Thread
Previous by Date
Next by Date
Contact
The TIFF Mailing List Homepage
This list is run by Frank Warmerdam
Archive maintained by AWare Systems
Thread
2000.10.05 05:26 "Re: Varying BitsPerSample", by Sam Leffler
> This was a conscious design decision based on my
> experiences--that the vast majority of usage had each sample the same width
> and that it wasn't worthwhile adding the complexity of varying bits per
> sample.
One other thing regarding this....
Every time someone would ask me to support something like this (varying
bits/sample) we found other methods for handling their needs using
facilities the library already supported. For example, the usual reason
folks asked for vary bits/sample was that they had an alpha channel or
similar that was different from the other channels. Rather than pack the
data together it was better to just split the alpha data into a separate
image/IFD within the same file. This allowed, for example, a different
compression scheme to be used for each set of data. The only reason I can
think of to have varying bits/sample is to support hardware codecs that
can't split their data streams.
It's possible to support everything in the TIFF spec but I long ago decided
that it was better for the library to handle only a "reasonable subset" and
support that stuff as well as possible.
Sam