HTPC: 1080p/24 and refresh rate

[MaxBD]

I use an HTPC as my BD player:

CPU: Q6600
GPU: AMD 5850 (Catalyst 11.2)
RAM: 8GB
BD: LiteOn iHES206
OS: Win7 Ultimate x64
Player: PowerDVD 10 Ultra MarkII (with latest patch)
TV: LG 42LG50

I'm a bit confused on the whole 24p issue. I searched several forums looking for a "best practices" guide on this topic, but I got conflicting opinions.

I think my TV is 24p capable because if I set the refresh rate on the HTPC to 24Hz, the TV info panel reports 1080/24p instead of the usual 1080/60p. Also, when the refresh is set to 24Hz, the mouse pointer is not as smooth as usual. This, I think, means that the TV is actually handling the 24Hz correctly.

At 24Hz, playing back videos from BD works well for the most part, but from time to time I notice some stuttering for a second or two. Nothing major, but it's a bit annoying.

At 60Hz, the stutter seems to happen less frequently, but it's still there. Bottom line I'm not sure what is causing this because I'm sure my HTPC has enough "horse power" to handle BD playback without breaking a sweat, so I suspect the problem must be software (PowerDVD, drivers, pulldown/interlacing settings).

Any suggestion is welcome. Thanks.

[mkohman]

Set your graphics card to 50 Herts and use 24hz in the settings of your player it should do the trick

[boredandlazy]

I'm curious as to why that'd work?

[MaxBD]

The software player doesn't have a 24p setting, so that's part of the problem. After a bit more testing it seems to be working well with the default refresh rate of 60Hz.

There seems to be no more stuttering and I even tried a judder test and everything looked smooth, so I guess the video card is doing the reverse pull down in the background.

[kujina]

Set your ati card to 23 herz, 23 herz is actually around 23.976, the same as blu ray films.

[MaxBD]

Thanks, that worked!

[Ragnarok]

Originally Posted by kujina

Set your ati card to 23 herz, 23 herz is actually around 23.976, the same as blu ray films.

What this guy said, HDDVD is 24hz on the button not 23.976.

It baffles me why the BD group didn't go for 24hz but, re clock fixes that.

[HDTV1080P]

Originally Posted by Ragnarok

What this guy said, HDDVD is 24hz on the button not 23.976.

It baffles me why the BD group didn't go for 24hz but, re clock fixes that.

Blu-ray uses both 24Hz and 23.976Hz. I have seen Blu-ray titles with both 24Hz and 23.976Hz. It would be ideal if in the future Blu-ray computer software would offer a 24P button to send native 1080p/24 to the graphics card. Every Blu-ray player software currently sends 60Hz to the graphics card, then some graphics cards do a reverse 3:2 pulldown to output 1080p/24.

In the future it is possible to bypass the 3:2 pulldown process if the Blu-ray software player engineers would start designing a feature that would output native 1080p/24 to the graphics card. A software engineer should be able to create a 24P button in the Blu-ray software program with some type of data flow to certain models of graphics cards that support 1080p/24 output.