AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2016.11.12 20:16 "[Tiff] Libtiff 4.0.7 release pending ...", by Bob Friesenhahn
2016.11.21 19:36 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:29 "Re: [Tiff] 12 bit byte format", by Kemp Watson
2016.11.21 19:07 "[Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:20 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:31 "Re: [Tiff] 12 bit byte format", by Bob Friesenhahn
2016.11.21 19:21 "Re: [Tiff] 12 bit byte format", by Kemp Watson
2016.11.21 19:25 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:32 "Re: [Tiff] 12 bit byte format", by Kemp Watson
2016.11.21 19:35 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:32 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:43 "Re: [Tiff] 12 bit byte format", by Bob Friesenhahn
2016.11.21 19:45 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:54 "Re: [Tiff] 12 bit byte format", by Bob Friesenhahn
2016.11.21 20:28 "Re: [Tiff] 12 bit byte format", by Kemp Watson
2016.11.21 21:05 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 21:04 "Re: [Tiff] 12 bit byte format", by Aaron Boxer
2016.11.21 19:42 "Re: [Tiff] 12 bit byte format", by Aaron Boxer

2016.11.21 19:29 "Re: [Tiff] 12 bit byte format", by Kemp Watson

But then, aren¹t you decompressing 16-bit images?

W. Kemp Watson
kemp@objectivepathology.com

Objective Pathology Services Limited
www.objectivepathology.com
tel. +1 (416) 970-7284

From: Aaron Boxer <boxerab@gmail.com>
Date: Monday, November 21, 2016 at 2:25 PM
To: Watson Kemp <kemp@objectivepathology.com>
Cc: TIFF mailing list <tiff@lists.maptools.org>
Subject: Re: [Tiff] 12 bit byte format

On Mon, Nov 21, 2016 at 2:21 PM, Kemp Watson <kemp@objectivepathology.com>
wrote:
> Do you have control of the original writing end of the data? If so, why not
> store as 16-bit? Vastly easierŠ

Thanks. The data is stored in 16 bit, with tag indicating 12 bits used.
But, when I read the data with tifflib, I get the format I mentioned
earlier.
The strip is returned in 12 bit.

>
> W. Kemp Watson
> kemp@objectivepathology.com
>
>
> Objective Pathology Services Limited
> www.objectivepathology.com <http://www.objectivepathology.com>
> tel. +1 (416) 970-7284 <tel:%2B1%20%28416%29%20970-7284>
>
>
> From: <tiff-bounces@lists.maptools.org> on behalf of Aaron Boxer
> <boxerab@gmail.com>
> Date: Monday, November 21, 2016 at 2:07 PM
> To: TIFF mailing list <tiff@lists.maptools.org>
> Subject: [Tiff] 12 bit byte format
>
> I am decompressing 12 bit RGB images, on little endian system.
>
> Each channel is stored in 3 nibbles: for example red is stored as
>
> 0xR2 R1 R0
>
> where R2 is the largest address, R0 is the smallest.
>
> When reading a strip, the nibbles are stored in the memory buffer as follows,
> in order of increasing memory address:
> (brackets indicate bytes)
>
> Lowest address.... (R1 R2) (G2 R0) (G0 G1) (B1 B2) (R2 B0) (R1 R0)....
>
> Is it possible for libtiff to store the nibbles as follows:
>
> R0 R1 R2 G0 G1 G2 B0 B1 B2............
>
> (sorry for the non-standard notation here)
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