2007.07.03 18:37 "[Tiff] BigTIFF extension?", by Phil Harvey

2007.07.04 17:26 "Re: [Tiff] 16-Bit-Per-Channel Lossless Compression", by Andy Cave

PS With LZW, have you tried with prediction enabled? That should improve the compression ratio on 16 bit ints.

----- Original Message -----

From: "Andy Cave" <andy.cave@hamillroad.com> To: <tiff@lists.maptools.org>; "Stephen Carlsen" <sc42business@mac.com> Sent: Wednesday, July 04, 2007 6:24 PM Subject: Re: [Tiff] 16-Bit-Per-Channel Lossless Compression

Are you saying that LZW or Flate do not get 2:1? Have you tried either of these? What ratios do you get?

Do you have some example files for testing with?

I think if you can compress and write to disk faster than you can write, compression is always worth it. Sure storage space is getting larger and faster, but then CPUs are getting more and more cores, which can nicely do compression in parallel.

It seems to me that none of the lossless compression schemes commonly used in TIFF are very effective at compressing 16 bit or 32 bit data. And, with technologies such as Camera Raw gaining in popularity rapidly, there's a lot more 16 bit data out there.

If we can come up with a simple approach that gives us on the order of 2:1 compression of 16 bit photographs, is this useful, or are storage space and bandwidth now so inexpensive that we don't care any more?