Performer and 50hz Video

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Franz Novak (franzn++at++hobbes.vienna.sgi.com)
Thu, 25 Apr 1996 22:39:24 +0000

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 ?

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.

Thank you in advance for your help.

Best regards

Franz

-- 


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 | Franz Novak           | System Engineer          |                    |
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