Re: OpenGL vs QuickTime for slideshow transitions
Re: OpenGL vs QuickTime for slideshow transitions
- Subject: Re: OpenGL vs QuickTime for slideshow transitions
- From: "R. Scott Thompson" <email@hidden>
- Date: Thu, 30 Sep 2004 14:39:54 -0500
On Sep 30, 2004, at 2:09 PM, Paul Collins wrote:
Our Envision application* includes slideshow functionality with wipes
and dissolves using NSImage / Quartz drawing. We'd like to switch to
either QuickTime or OpenGL to do these transitions more efficiently.
So far, it seems like either system is capable of displaying two
static images and doing a transition from one to another. iPhoto uses
OpenGL; I'm not sure which Keynote uses for it's lovely 3D
transitions.
My impression is most people prefer OpenGL for this sort of thing, but
QuickTime may be a great deal easier to code to (and may well use
OpenGl itself). So why not do things the easy way and use QuickTime?
Just some thoughts on the subject:
OpenGL is going to require the user to have a video card capable of
handling the transition code. The number of machines that aren't
capable of handling that kind of graphics processing are falling, but
there are still some out there. Depending on your market segment that
may be an issue. Also, using OpenGL you're going to have to write a
lot of the transition code yourself. For simple things like cross
dissolves and such, that should be pretty easy. For more complex
transitions, however, maintaining your own code may be more trouble
than it's worth.
QuickTime has a large number of built in filters, effects, and
transitions. The perform reasonably well and don't require special
hardware. I don't know how many third-party transitions etc... are
available, but the QuickTime transition architecture is extensible in
theory. As Mac OS X matures, there is a higher chance that the
transitions it has will be accelerated when appropriate hardware is
available.
Depending on your system requirements, a third option is to look at
Core Image. The only public information available on Core Image that
I'm aware of is found at:
http://www.apple.com/macosx/tiger/core.html
But as you can see from the bullet list at the bottom of the screen,
there are a large number of filters and a few transitions available
through core image. The document above also mentions that Core Image
takes advantage of the GPU when available so it promises to be very
high performance. Core Image is also mentioned to be extensible by
third parties which means you wouldn' t have to maintain all that code
yourself.
Scott
--
Macintosh Software Engineering Consulting Services
Visit my resume at <http://homepage.mac.com/easco/RSTResume.html>
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