Video Asylum

Posted by blue_z (A) on December 16, 2009 at 15:01:58

In Reply to: RE: If your plasma set is 1080 (1920 X 1080 pixels), it should be capable of displaying 1080P. posted by Audiophilander on December 15, 2009 at 23:42:03

Hi there

> If your plasma set is 1080 (1920 X 1080 pixels), it should be capable of displaying 1080P.

The signal that the TV can accept may be different from what the TV can display. The analog video signal path can easily be traced in a CRT TV. (I'm ignoring the DVI-D input of some Sony TVs.) But the analog and digital video inputs to a plasma or LCD TV are handled by an internal processor before the images get to the display.

> the difference between how interlaced signals and digital signals are displayed

These are not mutually exclusive: a digital signal can be interlaced.
Analog video can be progressive.

> ... so a 1080I (interlaced) image on a cathode ray set is doubled to resolve a smoother, line-free picture

There is no "doubling" for an interlaced signal. The even field draws the even-numbered horizontal scan lines and the odd field draws the odd-numbered lines to compose a complete frame. The temporal relationship between fields will depend on the source (video or film).

A "line-free picture" is a complex topic relating to scan line density and focus, not whether the signal is interlaced or progressive. FYI my CRT projector is feed a progressive video signal.

> Plasma sets, like LCD and DLP (but very much unlike CRT in this regard), are pixel based

The term usually applied to plasma, LCD and DLP displays is "fixed pixel", not "pixel based". Otherwise you seem to imply that CRTs don't understand "pixels". Use a strong magnifying glass to a direct-view CRT, and see the "pixels" just like on a direct view LCD or plasma. The "dot size" is the CRT specification that sets the effective native resolution of a direct-view color CRT. (Three-tube CRT projectors that do not need shadow masks are a different matter.)

BTW CRTs (not TVs but computer monitors) can display progressive video.

Regards

Edits: 12/16/09