View Full Version : HD70, 48Hz, Powerstrip = I Need Help


Jay_S
08-28-07, 04:37 PM
Good afternoon,

I have the Optoma HD70 1280x720 DLP projector. My modest and almost obsolete HTPC employs a Radeon 9600XT graphics card, and I have powerstrip installed. The 9600XT is connected to the projector via DVI-HDMI cable.

I have been living with 1280x720, 60Hz for a while, and it's ok. But (of course!) I think it can be better. So I'm trying to reduce judder. I believe that I can do this by setting Powerstrip's vertical refresh rate at an exact multiple of film's 24 FPS (or 23.976 FPS). Based on other posts in these forums, I believe my HD70 can output 48 Hz.

I believe Powerstrip is capable of MUCH more than I actually need it to do. What I mean is - without powerstrip, my HTPC can output 1280x720, 60Hz no problem to the projector, and everything is pixel perfect. I don't need to adjust resolutions or porches - I just need to be able to set 48 Hz vertical refresh rates.

With powerstrip, I can manually set 47.952 Hz and it will lock onto that frequency. I've also tried manually setting 48 Hz and it adjusts up and locks to 48.001 Hz. When I "apply" either of these frequencies, the HD70 will re-sync and display "1280x720, 48Hz".

But I think this just means that my projector can ACCEPT 48 Hz, not that it's technically outputting 48 Hz.

I can't hear the colorwheel spin down when changing refresh rates, but my ears are not so good anymore.

The question: Is there any way for me to objectively determine if the projector is outputting at 48 Hz?

I tried Re-Clock in combination with PowerStrip and got MORE "judder". Although reclock + ffdshow + limitedsharpen + etc is probably just too much for my lowly P4 (CPU usage averaged 70-80%), and what I am calling "judder" may have been dropped frames.

I also tried using re-clock WITHOUT powerstrip, sending 1280x720, 50Hz to the projector (which it also syncs to). The video is nice and smooth, but the pitch-shifting is too distracting.

Any suggestions?
Jay

vwbeetlvr
08-29-07, 06:31 PM
i found a way to output 47.952 on my video card to the hd70, gimme a few minutes and i'll post all the exact numbers. i dont know how technically correct they are, but the playback seems much better than 60hz, but doesnt seem perfect to me.

You have to type in these numbers 1280,440,25,225,1970,720,7,40,19,786 and the refresh rate should automatically adjust to 47.952

I did all this through trial and error, if anyone knows a better way please do tell.

http://img405.imageshack.us/img405/3844/47952dh7.jpg

vwbeetlvr
08-31-07, 10:10 PM
?

Jay_S
09-05-07, 05:21 PM
I emailed Optoma. Here's their response:

Hi Jay,

The projector is displaying a true 48Hz. Signal. The projector is capable
of displaying a true 48-60Hz. Signal.


Robert Sarauw
Optoma Technology, Inc.
715 Sycamore Drive
Milpitas CA 95035
Technical Support/Customer Care Supervisor
Email: roberts@optoma.com
PH: 408.456.3861
Fax: 408.383.3701

Mouw
09-05-07, 10:06 PM
I did all this through trial and error, if anyone knows a better way please do tell.

DownLoad this little program CR4V880 (http://rennfast.dns2go.com/Public/Momitsu%20DVD/Custom%20settings/cr4v880.zip)

BUTTON--Custom Resolution Wizard
enter 1280 Horz , 720 Vert, 47.952 Refresh

BUTTON--PowerStrip Conversion
gives you CORRECT #s

35.532-1280-48-128-176-1632
47.952-720-1-3-17-741

vwbeetlvr
09-07-07, 06:01 PM
DownLoad this little program CR4V880 (http://rennfast.dns2go.com/Public/Momitsu%20DVD/Custom%20settings/cr4v880.zip)

BUTTON--Custom Resolution Wizard
enter 1280 Horz , 720 Vert, 47.952 Refresh

BUTTON--PowerStrip Conversion
gives you CORRECT #s

35.532-1280-48-128-176-1632
47.952-720-1-3-17-741

awesome!!! thanks.