1080i Playback on LCD/Plasma at DVinfo.net

Lee Faulkner · March 7th, 2008, 09:17 AM

Hi

Please correct me if I'm wrong about any of what follows!

OK, so standard HDV is 1080i 60 fields per second (I know there are exotic variants .... but my question is only about the interlaced formats).

I believe that some OTA broadcasters are transmitting 1080i 60 fields per second (though not HDV encoded) and probably some HD cable and satellite providers too.

Now, a traditional CRT is a true scan device .... it can display interlaced fields and progressive frames (given it is designed to do so).

However, LCD and Plasma screens don't really 'scan'. They are fixed pixel devices which just change pixel output as required. I believe some don't even refresh all pixels every frame/field interval (if the pixel doesn't need updating). This makes them very suited to progressive display formats (duh) ... but what about displaying interlaced fields?

I know a dumb computer monitor will just display 2 interlaced fields as a progressive frame... unless software performs de-interlacing.

But what about an LCD/PLasma TV Monitor device receiving HDV or OTA interlaced HD via a component or HDMI input? Can it display true interlaced fields, one at a time? If so, what about the unused pixels not active during a the period of a field. Can it line double in each field to fill in pixels not being used in the active field? Or can it simply display true half vertical resolution fields one at a time?

Or ... does an interlaced input *have* to be de-interlaced to be displayed acceptably on a progressive screen (either in post production, prior to broadcast or in the TV itself)?

Maybe all these things happen .... or might happen, which is what really worries me!

Thanks for any insight.

Lee

March 7th, 2008, 09:17 AM	#1
Lee Faulkner Regular Crew Join Date: May 2005 Posts: 35	1080i Playback on LCD/Plasma Hi Please correct me if I'm wrong about any of what follows! OK, so standard HDV is 1080i 60 fields per second (I know there are exotic variants .... but my question is only about the interlaced formats). I believe that some OTA broadcasters are transmitting 1080i 60 fields per second (though not HDV encoded) and probably some HD cable and satellite providers too. Now, a traditional CRT is a true scan device .... it can display interlaced fields and progressive frames (given it is designed to do so). However, LCD and Plasma screens don't really 'scan'. They are fixed pixel devices which just change pixel output as required. I believe some don't even refresh all pixels every frame/field interval (if the pixel doesn't need updating). This makes them very suited to progressive display formats (duh) ... but what about displaying interlaced fields? I know a dumb computer monitor will just display 2 interlaced fields as a progressive frame... unless software performs de-interlacing. But what about an LCD/PLasma TV Monitor device receiving HDV or OTA interlaced HD via a component or HDMI input? Can it display true interlaced fields, one at a time? If so, what about the unused pixels not active during a the period of a field. Can it line double in each field to fill in pixels not being used in the active field? Or can it simply display true half vertical resolution fields one at a time? Or ... does an interlaced input have to be de-interlaced to be displayed acceptably on a progressive screen (either in post production, prior to broadcast or in the TV itself)? Maybe all these things happen .... or might happen, which is what really worries me! Thanks for any insight. Lee