Cisco DVR Installation Guide download pdf (Page 30)

Picture Formats

What Is the Difference Between a Standard-Screen and a

Wide-Screen HDTV?

The type of screen your HDTV has (wide-screen or standard-screen) determines how the

set-top displays programs on the screen. The picture format for an HDTV is a combination

of aspect ratio and screen resolution and is different for standard-screen and wide-screen

HDTVs.

What Is Aspect Ratio?

An aspect ratio is the ratio of the width to the height of the TV screen. The aspect ratios

differ because the television industry manufactures both standard-screen and wide-screen

HDTVs to appeal to consumer viewing preferences.

What Is the Screen Resolution?

The screen resolution indicates the amount of detail that the picture displays. Resolution is

identiﬁ ed by the number of display lines on the screen. The techniques that an HDTV uses

to “paint” the picture on the screen are referred to as progressive and interlaced.

With the progressive scanning method, the lines are drawn on the screen one at a time

in sequential order. Progressive scanning results in a more detailed image on the screen

and is also less susceptible to the ﬂ icker commonly associated with interlaced scanning. The

interlaced method involves refreshing pixels in alternation — ﬁ rst the odd lines and then

the even lines.

For advanced setup, select the screen resolution that your TV can support. Refer to your

HDTV user manuals to choose the proper screen resolution (480i, 720p, 1080i) for your

setup.

For example, a screen resolution of 1080i indicates that the screen shows 1080 lines in an

interlaced display, and 720p indicates that the screens shows 720 lines in a progressive

display.

A standard-screen HDTV has a 4x3

aspect ratio. The screen is 4 units wide

for every 3 units tall.

A wide-screen HDTV is one-third wider

than a standard-screen HDTV. The screen

is 16 units wide for every 9 units tall.

A screen resolution of 480i ﬁ lls the

screen.

A screen resolution of 720p or 1080i ﬁ lls

the screen.

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Cisco DVR Installation Guide Page 30