Re: live video texture -> frame rate
Salvador Cabaruvias (sal++at++mbsgi1.mdc.com)
Wed, 23 Oct 1996 09:48:19 -0700
On Oct 23, 7:10am, Orad Hi-Tec Systems wrote:
> Subject: Re: live video texture -> frame rate
> Meiner wrote:
> >
> > Hello,
> >
> > I'm trying to use live-video-textures within a performer-application. The
> > video-signal
> > comes from crystaleyes-cameras through the siriusboard into an ONYX with
RE2.
> >
> > The video-texture-stuff bases upon the 'vidtotex.c'-example coming with the
> > videolibrary
> > for the sirius-board.
> >
> I don't think vidtotex from SGI runs realtime, but...
>
> > Now, the problem is, that the framerate is going down to 20Hz when I'm
using the
> >
> > videotextures. I'm getting the videosignal noninterlaced, so it should be
> > possible to
> > get a framerate of 50/60Hz.
> >
> > The bottleneck seems to be the GL's 'subtexload'. I found it very
surprising
> > that the frame
> > rate stays the same, no matter if I grab 1024x1024 or 1024x512 pixels from
the
> > siriusboard.
> >
>
> Video textures in RE2 require *very* special care
>
> 1. Use 1024x256, even if you have PAL (yes, you loose the last 32=576/2-256
lines)
> 2. Use RGB5 internal texture format (PFTEX_RGB_5 in performer, GL_RGB5_EXT
> in OpenGL, TX_RGB_5 in IrisGL)
> 3. Make sure your video source, Sirius, *and* graphics (DG) are all in sync.
> 4. Make the subtexload the last GL command (after the drawing, before the
next
> vertical sync)
> 5. If the time you issue the subtexload is later than 11 ms after the start
of
> the frame, you can forget about real-time. (This is for PAL, NTSC is
about 8.5 ms)
> 6. If NTSC, you'll have to get some late Sirius patch for 5.3, or use 6.2
>
>
> > So if anybody has an idea, ...
>
> Buy an iR.
^^^
Even that is not a sure bet. I have one with sirius option and it
took several patches, etc... just to get the examples working with OpenGL. I
am now working on getting the Performer examples working. Oh what is fun!!
--
--------------------------------------------------------------------------------
Salvador Cabaruvias | sal++at++sgidev.mdc.com |
--------------------------------------------------------------------------------
CSSL | "Well I be done seen about every
McDonnell Douglas | thing when I see an elephant
(310) 593-6719 | fly" --Dumbo--
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