DrMordrid--need clarification...if you could?

[ffynnon]

I ran across a post of yours but now can no longer locate it.

I'm interested how you were able to have your G200 Marvel capture RGB @24bit 640x480 etc.

I bought my Marvel used, and I have one card and the bob. Am I missing something here?

Drivers are as follows:
BIOS: 1.6-15
Display driver: 4.11.01.2500
Matrox PowerDesk: 5.50.010
Video Tools are 1.52

The hightest RGB I can even choose is 16mil colors @ 160x120.

Were you monkeying with the registry or such? I would LOVE to be able to capture uncompressed video. I'm looking into a RAID, and this would ROCK!

Anyhow, if you have time to reply I would greatly appreciate it!

Thanks!

[DrMordrid]

This is something you can only do if your drive subsystem is fast enough to support it.

To capture RGB at 640x480 your drive subsystem has to be capable of 27.1 megs/second sustained sequential writes MINIMUM. At these rates you use up 1.7 GIGS per minute of video.

Another option is to use the YUY2 reghacks to activate YUY2 captures from AVI_IO or some of the other non-Matrox capture programs. These can be done at 704x480 and require slightly less in the way of throughput: 21 megs/second and 1.2 gigs per minute of video.

These capture modes are ONLY possible if you have a large, and very fast, RAID array.

My setups:

System 1. Fasttrak with four 10 gig 7,200 rpm Maxtor drives. 40 gigs. Max rate: 28 megs/second.

System 2. Fasttrak66 with two 18g 7,200 rpm IBM drives. 36 gigs. Max rate: 32 megs/second.

Soon System 1 will have a Fasttrak66 with three 40 gig Maxtor ATA66 7,200 rpm drives in a 120 gig array. Max rate: unknown, but I can't wait to find out ;-))

Even with these setups I only use RGB (or YUY2 for that matter) for special effects sequences or chromakeying as the files are too large for whole projects.

Dr. Mordrid


[This message has been edited by DrMordrid (edited 02 March 2000).]

[ffynnon]

Thanks for the quick reply! I must say that's an impressive system!

I'm curious though, when I eventually set up a RAID, will the Video Tools automatically realize this and allow me to capture at these settings, or do I need to re-install?

[DrMordrid]

You should re-run the Matrox HDBenchmark program if for no other reason than to be sure the entries it produces are in the registry.

That said this program is notoriously inaccurate and usually underestimates the speed of the drives.

To correct the results it produces I manually enter corrected figures obtained from SiSofts SANDRA benchmark program. There is a free shareware version at:

http://www.sisoftware.demon.co.uk/sandra/

SANDRA has multiple modules, one of which is a very good drive bench proggie. I take the "Sequential Write" figure from its detailed report and then follow this procedure;

Go to START/Run and type Regedit. Once its running browse to

HKEY_LOCAL_MACHINE/Software/Matrox/Vidpres/HDBenchResults/....

At this point you'll see the drive letters tested by HDBenchmark. When you select one you'll see this in the right panel:

(Default) xxxx

where xxxx is the HDBenchmark speed reported for that drive in kilobytes.

Doubleclick on (Default) and a dialog with this value will be presented. Replace it with the value obtained in SANDRA in kilobytes and close the dialog using OK.

Repeat for each tested drive and close RegEdit.

The next time you start the Video Tools it'll take effect. If your result was > 27.1 megs/second all the RGB settings should be available.

Dr. Mordrid




[This message has been edited by DrMordrid (edited 02 March 2000).]

[Phire]

How fast does your hard drive have to be to write RGB 16-bit 352x240 30fps..

[salacious]

640x480x3x30=27MBps

For 352x240x2x30=5MBps
You might not be able to capture in 16 bit colour, if you had to do it in 24 bit
352x240x3x30=7.4MBps

So the equation is of bytes per sec
xres * yres * BitsPerPixel/8 * FramesPerSecond
divide by 1048576 to convert into MBps