Re: Graphics on the net?

[jlee@ics.uci.edu (Orion Pax)]

Nathan Mates (nathan@cco.caltech.edu) wrote:
: >On the other hand, Jpeg's seem to produce great graphics, but the
: >only Jpeg IIGS Jpeg decoder that I'm aware of is lacking due to 2
: >reasons...it's only grayscale, and there are no conversion possible.

:    There are unix programs to go from jpeg to gif. (The conversion
: is mostly a lot of floating-point number crunching, which is why
: you do NOT want to do this on a GS if at all possible). But, as I
: said earlier, jpegs tend to have a higher quality source to start
: with, so you get better results out on the other end.

I've been mucking around in jpeg v5 beta source and it most of the floating
point operations have been shifted into 32-bit integer multiplications.
This is easy to speed up with tables and about a 60% increase in speed
over Orca/C.  Also, this src also includes a fast lower quality conversion
along with picture down-scaling at the same time.

However, 32-bit multiplication not the only speed bottleneck.  The huffman
compression routines could be speeded up if they were full asm instead of C.
I could've found more possible places for speed improvements, but Orca/C +
Prizm doesn't like to profile a 1 mb executable. :/

Joseph
--
jlee@clyde.ics.uci.edu   | Have you watched your Koko Wa GreenWood, Yotoden,
-------------------------+ Gundam 0083, Bubble Gum Crisis/Crash!, Video Girl
II(> Creative 'Ware <)II | Ai, Tenchi Miyou, Ah! My Goddess, Maison Ikkoku,
 Cal-Animage Epsilon VP  | PatLabor, Ranma 1/2, and Five Star Stories today?