2018.05.11 01:43 "[Tiff] LZ4 compression", by fx HAYAKAWA MICHIO

2018.06.08 01:51 "Re: [Tiff] LZ4 compression", by Kemp Watson

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> 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  */

Cc: fx HAYAKAWA MICHIO <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