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Each video format is named with a number and a letter: 1080i
and 720p are high-definition formats, 480p is known as
enhanced-definition, and 480i is standard-definition.
The number indicates video resolution: how many horizontal
lines of information make up a single frame of video. Generally,
bigger numbers mean sharper, more detailed images. The letter
indicates the method of scanning: interlaced or progressive.
With interlaced scanning (1080i & 480i), the horizontal lines in
a video frame are divided into two groups. If you were to
number the lines from the top to the bottom of the screen, one
group would be the odd numbered lines, and the other would be
the even numbered lines. All the odd lines, then all the even
lines, are refreshed 60 times per second, alternating between the
two. This means the whole video frame refreshes 30 times per
second. This is fine for smaller screens but can result in
flickering on larger screens.
Progressive scanning (720p & 480p) refreshes the whole video
frame (all even and odd horizontal lines) 60 times per second.
This eliminates flicker but requires the TV to process more
information since twice as many frames are displayed each
second.
Native, Hybrid, and Fixed Formats
Just as TV programs are broadcast in a variety of formats, TV
equipment receives and displays video in a variety of formats. For
any given program, the broadcast format may or may not match a
format that your HDTV is capable of displaying.
The TiVo DVR offers three types of formats which control how
broadcast signals are converted—if at all— for display on your TV.
Native (Recommended). When you use native format, the DVR
sends all video in its original broadcast format, with no
conversion. Native mode is recommended if your TV supports
all four formats. It’s also a good format to choose if you consider
yourself an HD novice.
Hybrid. When you use a hybrid format, the DVR converts
standard broadcast signals to 480p. It converts HD broadcasts to
the HD format you choose. Hybrid is recommended if your TV
supports either 720p or 1080i, but not both.
Fixed. When you use a fixed format, the DVR converts signals
broadcast in other formats to the fixed format you choose, and
video is always displayed in this format. Choose the fixed
format that matches your TV’s highest resolution. Using a fixed
format eliminates any screen flicker associated with switching
formats automatically, as occurs in native or hybrid modes.
See “Video Settings” on page56 for more.
Choose What Looks Best to You
You should feel free to experiment with all the different video
formats that your TV and the TiVo DVR support. You may find that
some formats are better suited to certain programs than others.