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September 2004

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2004.09.16 19:12 "BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.16 19:23 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.16 19:36 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.16 19:38 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.16 20:08 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 01:14 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.16 22:39 "Re: BigTIFF Tag Value Count issue", by Ian Ameline
2004.09.17 00:09 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 00:32 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 01:54 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 02:29 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 02:58 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 03:08 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 04:20 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 04:39 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 11:25 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 14:31 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 14:40 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 15:02 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:41 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 14:53 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 15:06 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:36 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 05:46 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 11:40 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:11 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 13:34 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 15:10 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 15:10 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 15:55 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:00 "Re: BigTIFF Tag Value Count issue", by Frank Warmerdam
2004.09.17 16:33 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:13 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 16:34 "Re: BigTIFF Tag Value Count issue", by Fernando Loygorri
2004.09.17 16:43 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:48 "Re: BigTIFF Tag Value Count issue", by Ross A Finlayson
2004.09.17 22:15 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn
2004.09.17 21:41 "Re: BigTIFF Tag Value Count issue", by Chris Cox
2004.09.17 11:38 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 06:35 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 11:43 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 12:46 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 12:55 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:20 "Re: BigTIFF Tag Value Count issue", by Rob Tillaart
2004.09.17 13:47 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.17 13:08 "Re: BigTIFF Tag Value Count issue", by Ross A Finlayson
2004.09.19 12:31 "Re: BigTIFF Tag Value Count issue", by Andrey Kiselev
2004.09.19 16:43 "Re: BigTIFF Tag Value Count issue", by Joris Van Damme
2004.09.20 16:18 "Re: BigTIFF Tag Value Count issue", by Ed Grissom
2004.09.20 22:05 "Re: BigTIFF Tag Value Count issue", by Steve Carlsen
2004.09.20 23:09 "Re: BigTIFF Tag Value Count issue", by Bob Friesenhahn

2004.09.17 21:48 "Re: BigTIFF Tag Value Count issue", by Ross A Finlayson

> > Just to clarify, I'm not proposing that negative 64-bit values should
> > have any meaning. They should be outlawed by the spec. I'm proposing
> > that the spec outlaw values with the most-significant bit set, and
> > this only to accommodate languages like Java that have a 64-bit signed
> > type but no 64-bit unsigned type.
>
> There is also the option to use 64-bit unsigned types, but some
> implementations may be severely limited by only supporting 63-bits
> (gasp!). Hopefully I will still be alive when that last bit becomes a
> serious issue. :-)
>
> I suggest that we stick with the 64-bit unsigned types with the
> recognition that many systems/implementations have limited
> capabilities.  Signed vs unsigned is a minor issue as compared to
> system limitations.

Hi,

I agree with Fernando, et al., that "Baseline" BigTIFF or so only require
63 of 64 bits in offset with file size support to 2^63-1.  Any software is
obviously free to support 64 bits in the 64 bit offset, but actually as
some system file APIs such as UNIX do use signed offsets, those that don't
should still offer relatively uncomplicated standard conformance.

I guess it is so that TIFF 6.0 has a maximum file size of 2^32-1 utilizing
the high bit of the 32 bit offset, but I think as register sizes probably
increase to 128, 256, etcetera in the near future that that one extra bit
decrease from 1/32, to 1/64, to 1/128, etcetera, of the available
precision, with less significance for the offset yet still the
flexibility of the I/O function to return an inline non-integer response
code, in this case "EOF", also known as -1L or -1LL.

TIFF is a vendor standard, if the standard says baseline support is 64
bits, then application vendors can implement it, particularly in
generation of the files where an application that demands just barely 4
gigabyte images would probably not require 2^64 bits to represent its
data.

BigTIFF will be a useful file format for uncompressed video and
tomographic imagery, except for lacking a timebase and other information
general to the entire file and being less for lossy compressed motion
picture imagery that often uses interframe differencing, with the rich
image expression gamut of standard TIFF tags that could be used basically
unmodifiedly.

Extending the width of the field tag and field type elements to 32 bits is
probably a good idea.  Having an extra field for application data for each
tag with the dictum that the private data must not be necessary to decode
standard public tags for image conformance would be useful and aid in
structure alignment for software uncaring of the private data.  Having an
extra data item for each strip or tile would be complicated and probably
unnecessary.


Warm regards,

Ross F.