1080p 50/60Hz

getafix · **30th July 2008, 08:23 PM**

Hi there

This may be a noob question, but here goes.

My LCD has a native resolution of 1080P. I am using a GA-MA780GM-S2H motherboard and am using Catalyst 4.75 (came with the installation DVD).
I am able to set my resolution to 1080P 50Hz which I believe is a good thing considering I am from South Africa and like you guys use PAL.

My problem is this. I have my HD DVD drive connected to my MCE machine and run PowerDVD 7.3. If I play a HD DVD at 1080P 50Hz, the picture flickers, but at 60Hz, it is fine.
I am connecting via HDMi cable.
If I play SD Dvd's at 50Hz, it is fine and doesn't flicker, it's only on HD movies.

What is the reason for this and should I be "concerned"

Cheers
G

logifuse · **30th July 2008, 11:56 PM**

Hi Getafix,

For starters, you could probably benefit from more recent ATI/AMD drivers.

Now, the reason it flickers is most likely the content on the HD discs is 24p or 60i meaning it will always be better at 60Hz (look up 3:2 pull down).

There have been a few attempts to make short cuts to switch frequencies - have a look for 50hz 60hz switching.

Also, your screen might support 1920x1080@24p - that will usually be best for non broadcast HD content.

Justin

getafix · **31st July 2008, 12:58 AM**

Hi Justin.

I have read that people have had problems with catalyst 8.6 so I have stayed away from it. Maybe I am wrong.
Are you talking about the onboard AMD chipset or my processor driver. I am running a Phenom 9750.
Would you suggest to change my res to 1080p 24hz. Would I then experience problems watching 50hz movies (if that makes sense)

Thanks
Gareth

logifuse · **31st July 2008, 08:17 AM**

I was suggesting updating your video drivers, but you don't need to.

Your best option is going to be to run at 50Hz for TV & then change to 24Hz (or 60 if you can't run 24) for HD movies/US content.

Justin

merovingian · **31st July 2008, 01:21 PM**

Quote:

Originally Posted by getafix

If I play SD Dvd's at 50Hz, it is fine and doesn't flicker, it's only on HD movies.

PAL DVDs encode the 24fps movie at 25fps (just like PAL broadcast TV), and hence PAL DVDs are designed for interlaced output at 50Hz. As Justin explained, Bluray and HD-DVD films are generally encoded as 1080p24. If your gear can't do 24Hz (or some multiple of), then 60Hz will give better results than 50Hz, as Justin said.

getafix · **31st July 2008, 06:04 PM**

Thanks, and understood.

Cheers
G

getafix · **2nd August 2008, 01:37 AM**

Update.......

I don't have an option to use 24 or any multiple there of. I will have to stick with changing between 50-60hz.

Thanks for the help in clearing things up.

G