Hi All,

My projector has a BenQ FP-591 with 16ms response time. It has never displayed movies smoothly, but I had always blamed that on the Nextvision N6.

I have since replaced the N6 with an HTPC, and the movies are still very unwatchable. Anything other than a very slow paced scene becomes very jumpy, and there are not enough sequential frames displayed to get a clear perception of motion.

I am currently running a P4 2.4(oc'd to 3ghz) FX5200 video card, with Zoom Player and fddshow SSE2. I am well below full cpu usage when resizing to 1024x768. fddshow says it's outputting around 30fps. It also says each frame is displayed for 50ms. I have to assume that this is a monitor problem.

Anyone have any advice? Could someone running ffdshow confirm that my numbers (especially frame duration) are correct?

Thanks,

Rhino

Anyway you can swap out the video card to eliminate it as the problem?

I can. The P4 isn't my true htpc. My htpc is a Barton 2500 with a Sapphire 9600xt, but is currently in the office because I'm missing the spdif header for the motherboard (and finding a replacement is damn near impossible)

If I cart the Barton rig downstairs, and I have the same effect, do you think that will elliminate the video card as a variable? I could pull it out of the system, but it is a bit of a pain because of the ducting in the case.

Rhino

Yes, just swap the P4 with the Barton. At least you're narrowing down the possibilities. If the problem goes away then you know it's somewhere in the P4. Then swap the video cards to narrow it down further. It's a process of elimination.

The monitor is nothing more that a few million transistors each of which drives a dot on the display, 3 of which together (RGB) make a pixel. The monitor can only display the image that its given at the rate at which it is provided. The monitor is totally passive and can't influence the display rate in any way. Ghosting is an artifact of the transistors not switching fast enough but the signal is updating at the speed that the video card is driving it. So the problem has to be in the computer side. Some LCDs don't like to be driven any faster than 60Hz so make sure that the frame rate is 60Hz. Turn off FFDshow to make sure that there aren't any issues there. The 50ms thing is strange the at 30 fps, the image should be updated every 33.3ms, at 60fps this should drop to 16.6ms. I can only guess that some strange combination of settings or interactions between filters in FFDshow is causing this. Even if this 50ms was true the frames would be updated at 20 fps which although not the best and not smooth should still look pretty good, many of those high compression video codecs for cellphones or to be used over dialup modems run at no more than 10 fps and don't look that bad. Major jumpyness seems more like an overloaded processor or some background task stealing too many cycles, so make sure that everything is turned off (no other applications, disable virus checkers, disbale any of those helper applications to see if that helps). One thing that I found after upgrading from a cheap video card to a nVidia FX6600 was that I needed to update the motherboard chipset drivers, 3D benchmarks that had been giving 15 fps results suddenly changed to 30+ fps. I've heard that for AGP cards the default memory window is too small and upping this size and making sure that the AGP is set to its maximum (4x/8x) can make major speed improvements.

I moved my HTPC down to the projector, and the problem still exists. Since this issue existed with the N6 as well, I really have to believe that it is a monitor issue. Both computers recieved clean OS installs about a month or so ago, and the HTPC has nothing installed except for updated drivers, zoomplayer, fddshow, and BTV (which is disabled before and DVD is played).

I have read that the FP591 has a built in auto scaler. I wonder if the lcd is scaling the 1024x768 signal after fddshow does? The lcd will not let me into the OSD, must be an issue with the control buttons.

Check the control buttons to make sure one or more are not stuck in the depressed state. Also check the cabling to the controls.

The buttons are not stuck, as I have the touchpad separated from the control board. The cables might be a problem, I will have to test them with a multi-meter tonight.

Are you using a low refresh rate? If your panel can do better than 60hz, trying boosting it through Windows or the N6 to 75 hz or higher.

(I know I'm kinda reaching here, but that's all I can think of. My panel only has a 25ms response time, but movies look great)