On Tue, 4 Dec 2001, Peter Good wrote:
> On Tue, 4 Dec 2001 17:15, Jeffrey W. Baker wrote:
>
> > Video RAM is nearly irrelevant. Anything with 2MB can do
> > 1024x768/16-bit which is what you want for DVD. For film-source DVDs
> > you want 72Hz or 96Hz refresh so you need a RAMDAC of 82MHz or 110MHz
> > respectively. The other consideration for video cards is that it really
> > must have an implementation of Xvideo for XFree86, hardware color space
> > conversion, hardware scaling, and it must have enough video memory
> > bandwidth to convert/scale at 1024x768/16.
> >
> > Briefly: you need at least a Matrox Millenium (c. 1995).
>
> > -jwb
>
> This might be a silly question, but why then, do they sell video cards now,
> with at least 8mb standard, with 32mb in a lot, and in my case 64mb? Just
> wondering.
Mainly for the gamers. In a direct-access video mode system (or even via
certain API's) the video memory is where scenes and other graphics are
buffered. The program just calls forth the particular segment of video
memory to display.
I admit that is a rather simplified version of what happens, but it
explains the basics.
DVD on the other hand is just a data feed from a data source... nothing
special about it. There are some video cards that if configured with
software correctly can use their video memory to decode the DVD stream
themselves, or even help accelerate the DVD stream (hence the terms
"hardware decoding" and "hardware acceleration" for DVD), but with any
reasonably fast machine (as in P2 500Mhz+) then you don't actually need
the extra decoding functions - unless you want more clarity out of the
picture - for example with a video projection system or something.
Honestly, the biggest reason why video cards have so much memory - the
hardware manufacturers can charge more if their card is better than the
competition's. And most programmers are lazy (no offense people, but I
have seen programs that are 40Mb+ that I saw back in the late 80's in only
4Kb...)
Hope this helps,
Cassandra
