- 2018.05.11 02:39 "Re: [Tiff] LZ4 compression", by Kemp Watson
- 2018.05.11 09:14 "Re: [Tiff] LZ4 compression", by Even Rouault
-
2018.05.11 12:50 "Re: [Tiff] LZ4 compression", by Bob Friesenhahn
- 2018.05.11 19:25 "Re: [Tiff] LZ4 compression", by Roger Leigh
- 2018.05.14 01:13 "Re: [Tiff] LZ4 compression", by fx HAYAKAWA MICHIO
- 2018.05.11 14:15 "Re: [Tiff] LZ4 compression", by Even Rouault
- 2018.05.14 23:51 "Re: [Tiff] LZ4 compression", by fx HAYAKAWA MICHIO
- 2018.05.15 22:00 "Re: [Tiff] LZ4 compression", by Bob Friesenhahn
2018.06.08 03:17 "Re: [Tiff] LZ4 compression", by fx HAYAKAWA MICHIO
I didn't check libtiff master repository at GitLab.
I believe reserving tags to avoid conflicts for feature enhancement is valuable. If Adobe get back, ask Adobe to approve them doesn't seem like a problem. Do you have any concerns about this
strategy?
Thanks,
Michio
-----Original Message-----
Cc: Even Rouault <even.rouault@spatialys.com>; tiff@lists.maptools.org
Subject: Re: [Tiff] LZ4 compression
Check what repository? I don't believe Adobe has got it back online yet - how can anyone register new tags when the registry has been removed? Does anyone even know what's in it?
Kemp
On Thu, Jun 7, 2018 at 8:29 PM, fx HAYAKAWA MICHIO <michio.hayakawa@fujixerox.co.jp <mailto:michio.hayakawa@fujixerox.co.jp> > wrote:
Oh sorry, Even! I didn't check the repository.
How about followings?
#define COMPRESSION_LZ4 34927 /* LZ4 */
#define TIFFTAG_LZ4QUALITY 65564 /* LZ4 acceleration factor */
Thanks,
Michio
-----Original Message-----
From: Even Rouault [mailto:even.rouault@spatialys.com <mailto:even.rouault@spatialys.com> ]
To: tiff@lists.maptools.org <mailto:tiff@lists.maptools.org>
Cc: fx HAYAKAWA MICHIO <michio.hayakawa@fujixerox.co.jp <mailto:michio.hayakawa@fujixerox.co.jp> >
Subject: Re: [Tiff] LZ4 compression
On vendredi 8 juin 2018 00:02:46 CEST fx HAYAKAWA MICHIO wrote:
> I successfully implemented LZ4 compression in libtiff on Windows platform.
LZ4 frame format is used for compression scheme. LZ4 frame is widely
> used for various applications.
Does anyone have any test images to see LZ4 compression characteristics?
I also modified tiffcp to support LZ4, so that any tiff files can be
converted into LZ4 tiff.
From my small experiments, its compression ratio is better than LZW,
> but worse than ZIP. Predictor is nicely working with LZ4. My tiff
> viewer shows
LZ4 tiff very fast compared to ZIP especially large tiff files. If
> someone want the code, I'd like to pick up two TAG values before
> releasing it to avoid confusion.
> #define COMPRESSION_LZ4 34926 /* LZ4 */
> #define TIFFTAG_LZ4QUALITY 65564 /* LZ4 acceleration factor */
Are there any objections to pick up those values?
Yes! libtiff master uses 34926 for ZSTD codec:
https://gitlab.com/libtiff/libtiff/blob/master/libtiff/tiff.h#L191 <https://gitlab.com/libtiff/libtiff/blob/master/libtiff/tiff.h#L191>
--
Spatialys - Geospatial professional services
http://www.spatialys.com
_______________________________________________
Tiff mailing list: Tiff@lists.maptools.org <mailto:Tiff@lists.maptools.org>
http://lists.maptools.org/mailman/listinfo/tiff <http://lists.maptools.org/mailman/listinfo/tiff>
http://www.remotesensing.org/libtiff/ <http://www.remotesensing.org/libtiff/>