Javier Castellar (javier++at++sixty)
Mon, 27 Nov 1995 15:22:31 -0800
There is not filtering on the field creation from the frame buffer and the
maximum frame rate (swapbuffers) is 30 frames per second (25 in europe) since
we do not support swapbuffers between fields except on "sirius" formats. If
your frame rate target is 60hz or 50hz DO NOT USE THIS FORMATS.
If cheap encoders are chosen there is not interfield filtering and you can
expect a lot of flickering.
This is the cheapest solution if you need RS170A for low cost helmets (RGB) or
composite video for even cheaper helmets.
640x486_60 (aka NTSC)
n++at++640x480_60 (in MCO)
=======================
This are pure "VGA" non interlazed formats. The outgoing video quality is high
since there is no field subsampling. In order to encode to composite video a
scan converted is needed. Since the original source of fields is a complete
frame, with a minimun if filtering the results, even in composite video, are
very good. Off course it depends on the encoder/scan converted.
This is the best answer for medium resolution helmets beside the absolutely
perfect (and expensive) field sequential.
Here you can ran a 60hz on the image generation side and the cost/perfomance
ratio is fairly good (since you can get better antialiasing and fill rate
savings at a cheaper cost).
-Javier
--************************************************************************* * Javier Castellar Arribas * Email: javier++at++asd.sgi.com * * * Vmail: 3-1589 * * Member of Technical Staff * Phone: NEW! (415)-933-1589 * * Real-Time Graphics * Fax: (415)-964-8671 * * Advanced Systems Division * MailStop: 8U-800 * ************************************************************************* * Silicon Graphics Inc. * * 2011 N. Shoreline Boulevard, * * Mountain View, California 94043-1386, USA * ************************************************************************* "Violence is the last refuge of the incompetant" Hari Seldon
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