Grass Valley ProCoder 3 - Manual (Page 48)

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ProCoder 3
Video Parameters
Video Frame Size Displays the current frame size of the source file in pixels.
Frame Rate Displays the source file’s current frame rate in frames per second.
The higher the frame rate, the more frames that are stored in the
video file and the smoother playback appears. At lower frame rates,
playback will be jerkier.
Video Codec Displays the codec used to read the source file’s video. In order to
play the video, your system needs to have the appropriate codec
module installed. If the appropriate codec is not installed, the
system will not be able to play the video, and ProCoder will not be
able to convert it to another format. However, you can usually find
the codec you’re looking for on the Internet and then download and
install it, making it available to the system and to ProCoder, as well.
Interlacing Displays whether or not your source video is interlaced or not. If
your source file is interlaced, the drop-down menu displays which
field is stored first (lower/bottom or upper/top).
ProCoder determines how the frames of video are stored in
the source file. Non-interlaced video stores and displays entire
frames at one time. Interlaced mode splits each frame into sets of
alternating lines, called fields, and displays each field in succession.
In ProCoder, the Bottom field is the Lower field, and the Top field
is the Upper field. Specifying the incorrect field order will result in a
vertical jitter or ghosting during playback.
Aspect Ratio Displays the source file’s width-to-height ratio and its pixels. The
video aspect ratio is the display size proportion of width to height.
ProCoder has presets for both standard (4:3) and widescreen (16:9)
video aspect ratios. An improper video aspect ratio will result in the
image looking stretched or squashed, i.e. circles will appear as ovals.
The pixel aspect ratio determines the displayed “shape” of each
pixel. For computer use, pixels are normally square (1:1 ratio).
However, for television and video use, pixels are mostly (but not
always) rectangular. ProCoder has presets for square, television
and DV standard, television and DV widescreen, and anamorphic
pixel sizes. An improper pixel aspect ratio can cause the image to
appear stretched or squashed, as well as cause filtering and other
processing to appear strange. For example, a circle wipe may
display as an oval wipe instead.
While ProCoder is fairly accurate at determining the interlacing properties of your
source video, it’s not always right. For best results, double-check this parameter and
set it to the correct setting if it’s set incorrectly.
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