Dataton WATCHOUT User's Guide

• The origin of the movie; eg, computer generated or camera.
• The quality and “cleanness” of the movie’s source material.
• The codec used to compress the movie.
• The color depth at which the movie is stored.
When using material originating from video, the resolution is determined by
the video format; 720 x 480 for NTSC and 720 x 576 for PAL (DV). Sometimes,
using a resolution of precisely half the video resolution can be useful –
particularly for smaller video inserts. Reducing the size in this way dramatically
reduces the load on the computer for reproducing the material, and also
removes any interlacing artefacts from the resulting image. This may also allow
you to use a higher quality codec.
The frame rate for video is determined by the source format, with NTSC
playing back at 29.97 frames per second (fps) and PAL at 25 fps. Use the
“Base Frame rate” setting in WATCHOUT’s Preferences dialog box to tell
WATCHOUT which frame rate to optimize for (see “Base Frame Rate” on page
121).
Note that both the PAL and NTSC formats are interlaced, meaning that they
reproduce each image in two phases, called fields, each containing half of the
image’s resolution. When played back, these two fields are interwoven to
reproduce the full image frame. This may sometimes result in an undesirable
“comb effect” when played back on non-interlaced (sometimes referred to as
“progressive scan”) computer displays, such as those typically used with
WATCHOUT. This is particularly noticeable for objects moving horizontally, or
during pans. Some specialized applications, such as Media Cleaner Pro, can
de-interlace interlaced movie files.
68 Chapter 6: Media Files