33 ODROID-XU4 USER MANUAL
and 1080p as Full HD. The following comparison table lists the native
display resolutions along with some sources that use these resolu-
tions.
Standard Resolution Aspect Ratio Refresh Rate Typical Sources
1080p 1920 x 1080 16:9(1.78:1) 24Hz, 50Hz, 60Hz HDTV, Blu-ray
1080i 1920 x 1080 16:9(1.78:1) 50Hz, 60Hz HDTV, Blu-ray
720p 1280 x 720 16:9(1.78:1) 50Hz, 60Hz HDTV, miniDV
As a comparison, the standard DVD Video format uses a display
resolution of 720 x 480 with a 4:3 aspect ratio (non-widescreen). This
resolution is also referred to as D-1 video and is the standard used or
miniDV digital camcorders.
Progressive vs Interlaced Video
1080p and 720p are progressive video formats. For these for-
mats, a complete video image is transferred for each frame of the
video signal, so that a 60fps video displays 60 complete, full frames
per second. This format is visually superior to interlaced video, and in
general should be used when supported by your display.
1080i and 720i are interlaced video formats, and video interlac-
ing is the historical standard for broadcast video. In interlacing, two
frames (or more correctly, elds) are transferred for each frame of the
video signal, so that a 60fps video has 30 complete, full frames per
second. The display device sends the two elds to the screen in the
horizontal odd and even (or interlaced) pixel positions. Given the vi-
sual persistence of the human eye, this reconstruction of full frames is
undetectable to the viewer.
In general, faster frame rates result in a visually smoother video
playback, and interlacing results in a halving of the native frame/eld
transfer rate because two elds are required for the full image. Frame
rate and visual experience are subjective, however. Traditionally, mov-
ies produced with conventional lm use a 24 frames per second rate,
and many viewers prefer the cinematic experience that 24fps video
provides. In fact, much of the professional video produced with high-
end gear is actually shot at 24fps, and later converted to video frame
rates to provide the look and feel of cinematic lm.
Video Downconversion
When selecting a screen resolution for your XU4, you should
rst consult the specications for the display that you plan to use. In
general, using the native resolution of your display will provide the
best performance and quality.
For example, if you use a display that only supports native 720p,
and you set your XU4 to a 1080p screen resolution, it will probably
Chapter 3
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