Re: DNG as an ISO standard


"Wolfgang Weisselberg" <ozcvgtt02@xxxxxxxxxxxxxx> wrote:
David J. Littleboy <davidjl@xxxxxxx> wrote:
"Wolfgang Weisselberg" <ozcvgtt02@xxxxxxxxxxxxxx> wrote:

and secondly that if reduced to
optimized hardware rather than cpu cycles there would be an order of
magnitude gain in cycles as well as power.

I would like to see your implementation, then.

Not mine, but Canon's and Adobe's. The 1DIII produces compressed 10MP raw
(or jpeg) files at 10 fps. That's 100MP per second.

A rough timing of Photoshop CS3 saving a 90MP 6x7 scan to best quality
jpeg
(on a 4GB, 3.0 GHz core 2 duo with three 15,000 rpm disks) has it taking
about 9 seconds.

So two DIGIC IIIs are about ten times faster than two Intel CPUs.

Assuming that

No, this isn't assuming _anything_. This is real life. In real life, dSLRs
process images 10 times faster than PCs.

Which is exactly the result one would expect, since the dSLR is using
dedicated hardware. It's always been the case that (if you have the money)
you can speed things up (on a per processor basis) by designing dedicated
hardware, and image compression is exactly the sort of thing that this is
most applicable to.

David J. Littleboy
Tokyo, Japan

a) Photoshop can parallelize as well as Canon (one image,
one DIGIC III)

Photoshop is one of the very few apps out there that does parallelize.

b) 10*10 is aequivalent to 1*90 MPix (there's memory access
and cache sizes and stuff)

Compression happens in smaller blocks, so this is a reasonable comparison.
And there's no problem in fitting a 90MP images in memory.

c) the hard drive is not the bottleneck

15,000 rpm server class disks. Not a bottleneck.

d) Windows is not standing in the way (again)

This is XP, not 95.

e) Photoshop is speed-optimized for writing JPEG (instead of,
say, working on images) -- though of course you could use
something like cjpeg instead.

So do your own test. But you aren't going to find even the best hand coded
converters getting anywhere close to the DIGIC III on general purpose
hardware: computation doesn't work like that.

f) the JPEG settings are equivalent

The 1DIII shoots at 10fps whatever compression settings are used, which is
why I used best compression in photoshop: its moving somewhat less data per
MP than the 1DIII is with compressed raw.

David J. Littleboy
Tokyo, Japan


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