[Fwd: 16:9 Aspect Ratio]

[Dan.Strassberg]

Back to the video side: The names for the various video formats (for
example 1080p, 1080i) suggest that a 16:9 TV display should have 1080
pixels vertically (and 1920 pixels horizontally), or an integral
multiple thereof and that formats such as 720p would omit every third
horizontal line. I can't believe that's what really happens because I
believe that the omission would be very noticeable and very annoying
(especially in displays of small text). So what gives? If the picture
is transmitted with 1080 horizontal lines but the display has 1152
pixels vertically (perhaps a more convenient number than 1080 because
the largest common factor of 1080 and 1920 is 120, which is not an
integer power of 2, whereas the largest common factor of 2048 and
1152 is 128, which equals 2^7), it would suggest that the screen would
display a 1920 by 1080-pixel image letterboxed within the 2048 by
1152-pixel screen. Although the borders would be quite narrow (36
pixels top and bottom, 64 pixels left and right) is that what really
happens? I imagine not.

-----
Dan Strassberg (dan.strassberg@att.net)
eFax 1-707-215-6367

----- Original Message ----- 
From: "Dave Doherty" <dave@skywaves.net>
To: "Garrett Wollman" <wollman@bimajority.org>
Cc: <boston-radio-interest@bostonradio.org>
Sent: Friday, January 25, 2008 8:04 AM
Subject: Re: [Fwd: 16:9 Aspect Ratio]