Brian Furtaw (brian++at++dingbat.clubfed.sgi.com)
Wed, 14 Apr 1999 21:10:20 -0400
On Apr 14, 2:30pm, Geoff Levner wrote:
> Subject: Re: movie playback on Onyx2
> 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?
Already talked about this. Use xlv and stripped plexes. man on xlv_make will
help.
>
> > 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).
Maybe with the software compression and disk stripping you'll reach your goal.
>
> > 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?
Hold on i'll check, "DIVO [XIO card] includes real-time lossless data reduction
mode (Rice entropy-encoding scheme) that canreduce data bandwidth and storage
requirements by approximately 2:1." --- From the Onyx2 Digital Media glossy
>
> 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
>-- End of excerpt from Geoff Levner
--
----oOOo---- ----oOOo---- ----oOOo---- ----oOOo----
Brian Furtaw (brian++at++sgi.com)
Graphics Guru Office:(301)572-3293 Fax: (301)872-3293
12200-G Plum Orchard Drive OpenGL/Performer/OpenInventor/ImageVision
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