[mythtv-users] interlaced vs not?

Grant Edwards grante at visi.com
Sat May 1 13:42:01 EDT 2004


On Sat, May 01, 2004 at 10:05:03AM -0700, Chris Petersen wrote:

> In this way, bathroom tiles would be non-interlaced (like a
> trinitron), and bricks would be interlaced (like pre-trinitron
> monitors)...  Before trinitrons came along, the pixels of most
> monitors were arranged in a brick-type pattern, thus, people
> started calling them non-interlaced when trinitrons came out,
> with those nice even lines of pixels.
>
> However, You are probably correct in that they informed us
> badly.  the "brick" pattern of pixels was probably designed so
> that video-interlacing would be less obvious.

No, they were designed that way since it was the most efficient
tessellation of a plane for which manufacture of a shadowmask
and picture tube were mechanically feasible.  It's got nothing
to do with interlaced vs. non-interlaced video signals (they
both use the same phosphor patterns).  Phoshpor patterns and
video interlacing are independant and orthogonal concepts.

One is the physical pattern in which phosphor is layed on the
picture tube.  The other is the order in which scan lines are
transmitted.

The number of scan lines in an NTSC TV picture never changes.
It's 525 (or whatever).  The number of phosphor dots both
vertically and horizontally varies all over the place depending
on manufacturer and screen size.  A 5" screen and a 50" have
the same number of scan lines.  The 50" tube has way more
phosphor dots.  The pattern of the dots can also vary, though
there are a few patterns that work "best".

> But it still doesn't help me figure out if my source is
> interlaced or not...  I just have a standard analog cable
> setup, going into a PCTV Pro tuner card.  I'm assuming that
> this signal is NOT interlaced, but I'm warry of just assuming
> things.

Standard analog cable signals in the US are NTSC.  NTSC is
interlaced.

-- 
Grant


More information about the mythtv-users mailing list