Video Scaling Artifacts; Freeze Quality; Upside-Down Video - Videonics MXPro User Manual

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Videonics MXPro User Guide
V S
IDEO CALING
F Q
REEZE UALITY
U -D
PSIDE OWN
A
RTIFACTS
Reducing a video image's size can create artifacts because some picture information
must be discarded to reduce the number of pixels in the image. In some cases, picture
information might disappear when eliminating pixels. For example, lines in the image
might appear jagged when MXPro removes pixels and, therefore, parts of the line.
Some MXPro transitions scale an image down gradually. This might cause small fea-
tures to appear and disappear as the image scales down.
The artifacts described here are normal when performing advanced effects. They are
normally minor when running transitions at normal speeds.
You can set MXPro to freeze either a frame or a field (see "Force Field Freeze" on
page 76).
Freeze Field captures one field (half a video frame) and duplicates it to make the two
fields that comprise a frame. This eliminates flashing caused when an object occupies
a different position in the two captured fields, or when an object is so small it appear in
only one field. MXPro's Field Freeze eliminates flashing artifacts but reduces vertical
resolution because it shows only one field.
Freeze Frame captures all fields in the image. This produces a higher quality image,
but some flashing might occur.
V
IDEO
When you flip video upside-down (as occurs automatically with some transitions and
when using the Flip (vertical) option on the INPUT EFFECTS menu), the picture resolu-
tion reduces slightly and the frame rate also reduces to make the video image more
stable. The reduction is subtle with most video and most effects, especially those that
move quickly.
Appendix C