Hello, Colin Wright wrote: > A 50Hz country question about the new Dell LCD screen and in fact most fixed > pixel array displays (PDPs, etc) for home theatre or even notebook PCs - > they all have a single nominal 60 Hz vertical rate - only !!! It is true that many LCD monitors accept 60 Hz frame rate only. And even if they accept 75 Hz (because that is "more ergonomic"), it is possible that an internal scaler equipped with a frame memory converts that back to 60 Hz by dropping every 5th frame. Sometimes in the Lab we override the EDID data and use Powerstrip to operate an LCD at 50 Hz anyway, and usually that works, but you might see 25 Hz flicker from the inversion process, or non-uniformity from the pixel charging process. That is why manufacturers like to stay away from 50 Hz and design / optimize a panel for 60 Hz only. "Graphics standards are 60 Hz." Yeah right. Note that we have always been able to run our VIDEO displays (LCD and PDP) on 50 Hz, and sometimes even 48 Hz (for you guys). For plasma we have to make sure that the brightest sub-fields repeat at 100 Hz, or else the 50 Hz frame flicker would be intolerable. That problem is less severe at 60 Hz, so then the drive scheme can be optimized for other properties. We have the technology ("Natural Motion") to convert to 60 Hz, 72 Hz, 75 Hz, 90 Hz, 100 Hz, 120 Hz, take your pick, and we might apply that to eliminate the frame flicker. It is even available in software-only form for running on a Pentium-4 PC, under the trade name of "TriMension" (in WinDVD Platinum). > So is this the reason occasional picture stutter might be seen when showing > 25 and 50 frame per second video - or what mechanism/process removes this > and does this make these type of displays absolutely OK for critical picture > evaluation of material that may involve temporal artifacts (particularly if > trying to play out of a hi-grade PC GPU)? > Maybe Jeroen or others can offer an answer. I would recommend that you do not buy a display that is optimized only for 60 Hz graphics if your application is video. Flat panel TVs for 50 Hz countries should be able to receive 50 Hz on the VGA / DVI / HDMI inputs. But we have seen some exceptions, so you should try it before buying. (It's amazing what a fool with a frame memory can do to a video signal...) Best, -- Jeroen +-------------------------------+------------------------------------------+ | From: Jeroen H. Stessen | E-mail: Jeroen.Stessen@xxxxxxxxxxx | | Building: SFJ-5.22 Eindhoven | Deptmt.: Philips Applied Technologies | | Phone: ++31.40.2732739 | Visiting & mail address: Glaslaan 2 | | Mobile: ++31.6.44680021 | NL 5616 LW Eindhoven, the Netherlands | | Skype: callto:jeroen.stessen | Website: http://www.apptech.philips.com/ | +-------------------------------+------------------------------------------+ ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.