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To: Thomas Roell <roell@crab.xinside.com>
cc: Randall Hopper <rhh@ct.picker.com>, multimedia@freebsd.org
Subject: Re: Bt848 driver & Wincast -- some success 
In-reply-to: Your message of "Wed, 12 Feb 1997 08:06:51 MST."
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Date: Wed, 12 Feb 1997 12:32:46 -0800
From: Amancio Hasty <hasty@rah.star-gate.com>
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Mmmm.. I am still waiting on for a list of cards which I can install
on my system for dual display -- PCI cards.

BTW: I know about the advantage of YUY2 vs RGB to save bandwith 
however I don't have YUY2 support on XFree86 -- I could implement
but will see. 


	Cheers,
	Amancio

>From The Desk Of Thomas Roell :
> In your message of 11 February 1997 you write:
> 
> > Hi,
> > 
> > You need the B848 Databook from Brooktree if you want to hack on the
> > driver, period.
> > 
> > What is your CPU and motherboard chipset, example Natoma or Triton...
> > 
> > If you have a Mercury chipset, then you don't have enough PCI bandwith 
> > to drive a 640x480 32bits picture. Also try playing with the PCI parameters
> > in your BIOS. Your PCI clock rate should be around 32 or so and not 60 or
> > higher.
> > 
> > You can try 320x240 with something like 15bits or 8bits color depth.
> > 
> > The ghostimage that you are experiencing in your system is an indication
> > that your PCI chipset is not able to keep up with the Bt848.
> > 
> > The driver does not have the ioctls to transfer video to memory and
> > is not hard to add . I can provide this feature before the end of 
> > the week;however, if you want to take advantage of this feature
> > then you will have to ask the XFree86 team or peruse thru their 
> > release notes for an appropiate video card which supports linear
> > frame buffering.
> 
> *smile* Or Xi Graphics (the artist formerly known as ...)
> 
> Actually writing YUV422 and 320x240 makes more sence that 15bpp or
> 8bpp TrueColor. The graphics chip can do the color-space conversion.
> 
> What I'm really curious about is whether the Bt848 can do
> doublebuffering. I mean an even field into buffer A and an odd field
> into buffer B.
> 
> - Thomas
> -- 
>              Thomas Roell   /\       Ein Nasshorn und ein Trockenhorn
>              Xi Graphics   /  \/\ _    spazierten durch die Wueste,
>       roell@xinside.com   /   /  \ \    da stolperte das Trockenhorn,
>                          / Brumpft! \    und's Nasshorn sagte: "Siehste!"