Problems with using HDMI D:

[fffblackmage]

I was thinking this probably belongs to A/V & Home Theater, but this subforum just gets much more traffic.

I'm getting stuttering, ghosting, and input lag issues when I am using my HTPC, hooked up to the TV using HDMI. The TV is a Dynex 120Hz 1080p 55" LCD TV (model DX-55L150A11). The issues don't disappear when I disable features like "Noise Reduction" and "Dynex Motion 120Hz." However, playback is smooth and input lag seems to disappear when I use VGA instead of HDMI. I've tried another computer, same thing - HDMI has issues, but VGA is fine.

I wasn't able to measure the input lag when I hooked up the TV via VGA, but when I'm using HDMI, input lag averaged 133ms. Quite significant, especially compared to my monitor's (T260HD) ~25ms input lag. Input lag doesn't get any better if I disable the noise reduction and 120Hz motion features.

I'm actually satisfied with using VGA, but it would be nice just to get HDMI working right anyways. Any suggestions?

This actually isn't the first time I encountered issues when using HDMI. When I tried using HDMI on my monitor (T260HD), the gamma setting or something was just waaaay off. I couldn't even compensate for the error. I guess my monitor just handles HDMI differently than DVI.

HTPC:
E-350 with HD6310
4GB DDR3-1333
Windows 7 x64

"Another computer":
Phenom II X4 @3.5GHz
6GB DDR2-800
5870
Windows 7 x64

How I tested input lag:
Attach a CRT monitor, clone desktop, set up a timer, take pictures at 1/1000 shutter speed.
Hmm... I didn't think of this before, but I didn't use the native resolution. I have no idea if this could have any effects on results.

 

[Zap]

A lot of HDTVs will always run HDMI through a scaler, which adds latency.

Just use VGA. Much simpler.

 

[fffblackmage]

Oh yeah, I thought that was weird... when I first plugged in the HTPC via HDMI, the screen didn't fill all the way to the edges of the TV. I had to adjust overscan in CCC to fix it.

I was also hoping that turning off some post-processing effects would lower input lag, but that didn't do a thing. I can see why people didn't like the TV for gaming. Fortunately, I don't plan to do that, though it does work perfectly fine via VGA.

That "Dynex Motion 120Hz" thing is missing when using VGA. I don't mind, maybe because I'm not used to it, but it was definitely cool to see in action, except for the stuttering. Hmm... I wonder if the video renderer is causing the stuttering... will need to do more testing.