Re: movie playback on Onyx2

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Geoff Levner (g.levner++at++acsys.it)
Wed, 14 Apr 1999 14:30:08 +0200


Brian Furtaw wrote:
>
> Biggest issue is not the graphics but the disk drives. How many disks is the
> data spread across? How many SCSI controlers do you have on the machine? How
> many disks on the machine do you have that the data could be stripped across?

libmovie reads movies from a single file -- is is possible to spread movie
data across several disks? Or would we need to store the movie in single
image files, and write our own application to read them in and feed them
to the graphics pipeline?

> Do you have any fibre channel disk arrays?

No, this is for a commercial product and we do not want to require that
customers buy a disk array.

> 640x480x3_8_bit_channels_RGBx25FPS = 23,040,000 bytes per second

The quantity of data is reduced considerably by compression, though. I
figured that if we used compressed movie data, we would not be limited by
I/O bandwidth, but as I said, compressed does not work very well either
(a bit better than uncompressed, however).

> A SCSI disk controller can stream 20mBytes per second peak flow so we are
> talking a minimum of two controllers. Better performance can be had by
> stripping the data across several disk drives but you are still going to need
> two disk controllers. Do you have an MSCSI card or JPEG compression hardware. A
> cosmo compression card could get you down to one controller but it only runs on
> Octane.

Is there any compression hardware available for an Onyx2?

Thanks for your help,
Geoff

-- 
Geoff Levner -- g.levner++at++acsys.it
ACS Studio, via Aurelia 58, 00165 Roma, Italy
tel. +39-063936331, fax +39-0639363317

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