"Bill DeWitt" <bde### [at] cflrrcom> wrote in message
news:3ac71f3e$1@news.povray.org...
>
> "Stephen Bell" <ste### [at] yahoocom> wrote in message
> news:3ac68c86$1@news.povray.org...
> > I hadn't thought about that.  How does an animated GIF compress?
>
>     It doesn't. It uses every bit of information in the original image. It
> simply layers the image so that the different frames display sequentially.

I don't understand.  I thought GIF was "lossless compression".  It obviously
compresses the file size, because a single frame GIF with the same color
depth as a BMP of the same image is about a third of the size (I just
checked).

> > If more of
> > the image in different frames is changed, does it really affect the
> > compression?
>
>     Yes. Well, not the compression (see above) but the file size. Every
> pixel you remove saves space, and if you remove it over the rather large
> number of frames you have, it multiplies. BTW, how many frames -do- you
have
> and do you need them all? It seems -very- smooth and that is good, but
could
> you remove 10% and still have smoothness?

I don't understand what you mean by removing pixels... Please clarify.
I probably could get away with using less frames.  This was really just a
rough draft testing the capabilities of POV-Ray and dynamic HTML.

> > I'm using Microsoft GIF animator.  Is there a better program
> > out there?
>
>     I have never used it, but many programs will remove unchanged pixels
for
> you leaving a rectangle that contains all changing pixels. This requires
> that -all- pixels that do not need to change -really- don't change. No
> shadows, no radiosity, and often, no AA.

That may have been one of my problems as well.  I had radiosity on and I
hadn't really thought about how it would change the file sizes.  Do you mean
that the program would convert an animated GIF into a segment that was
animated and a separate still GIF?

> > Mostly I just need to reduce the color depth from 256 colors
> > down to a more reasonable level.  I think that would help a lot.
>
>     It would. Drastically. But you can reduce it to a reasonable level,
IOW,
> you don't have to go down to 16 colors, you could find the required number
> for your image. Also, a small decrease in height and width will return a
> large bonus in reduced file size.

I think if I used some more normal colors (ie. shades of gray for metallic
lever, or even just rusty colors) it would use less colors in the palette to
have the pieces all closer to the same shades instead of the awful colors I
have now (it was just a test after all).  Thanks for your input.

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