Re: Performer and 50hz Video

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Angus Dorbie (dorbie++at++bitch.reading.sgi.com)
Fri, 26 Apr 1996 00:31:42 +0100

On Apr 25, 10:39pm, Franz Novak wrote:
> Subject: Performer and 50hz Video
> Hi,
>
> a customer sent us to following questions concerning live video-input
> at 50 hz. Is this a known problem or is demo-code available where the
> customer can see how this is done?
>
>
> Here are the questions/problems:
>
>
> Problem 1:
> **********
>
> Hardware: Onyx RE2 / 4 RM5 / Sirius Option
> Library: Performer 2.0
> Display: 50 Hz
>
> Problem: We need to get a rendered scene with a live video-input at
> 50hz framerate.
>
> What we do have now:
> We got a stable framerate of 50 hz, but as soon as we
> turn on the live video-input and drain it to the RM, the
> framerate drops to appr. 25 hz.
> We use SIR_TEX_PACK_RGB_5 packing for the tex drain.
>
>
> What we tried:
> We tried to draw only the Live-Video Texture --> still
> appr. 25 hz framerate.
> We tried interleaved and non-interleaved --> no effect
> We tried PFTEX_LIST_APPLY and PFTEX_BASE_AUTO_SUBLOAD
> We tried to reduce the texture size from 1024*1024 to
> 512*512 --> the machine crashed.
>
> Question: Is there a way of getting Live-Video- input to texture memory with
> a 50 frames/sec ?
>
> It seems to us that the video-transfer blocks the rendering completely,
> because the sirius option has to wait until it gets a complete frame.
> We could also live with a quality penalty of the live input, but our
> framerate has to be stable 50 hz.
>
>
> Problem 2:
> **********
> Hardware: Onyx RE2 / 4 RM5 / Sirius Option
> Library: Performer 2.0
> Display: 50 Hz
>
> Problem: How do we get a texture on a loaded graphic e.g: .obj ?

Simply change the geostate or apply it & override in draw callbacks, use
texture matrix to scale existing coordinates or texgen if coordinates are
required.

>
>
> Problem 3:
> **********
>
> Hardware: Onyx RE2 / 4 RM5 / Sirius Option
> Library: Performer 2.0
> Display: 50 Hz
>
> Problem: As soon as our Live-video-texture gets into view, it sometimes
> happens that the video-input is drained to the wrong textures.
> It seems that the sirius board sometimes writes into the wrong texture
memory
> adress.
>
The target texture should be bound when loading the video image, could this be
your problem?
>
>
> Thank you in advance for your help.
>
> Best regards
>
>
> Franz
>
> --
>
> ***********************************************************************
> | Franz Novak | System Engineer | |
> | Silicon Graphics GmbH | | |
> | Modecenterstrasse 14 | franzn++at++vienna.sgi.com | |
> | A-1030 Wien | Phone: +43 1 7986848-517 | VoiceMail: 58025 |
> | Austria | Fax: +43 1 7986848-11 | Mail-Stop: IVA-309 |
> ***********************************************************************
>
>-- End of excerpt from Franz Novak

-- 
Angus Dorbie,
The Reality Centre,
Silicon Graphics Ltd, UK
dorbie++at++reading.sgi.com

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