Adobe After Effects CS4 - Manual (Page 96)

90 USING AFTER EFFECTS CS4
Importing and managing footage items
Last updated 12/21/2009
Importing and interpreting video and audio
High-definition (HD) video
High-definition (HD) video refers to any video format with pixel dimensions greater than those of standard-definition
(SD) video formats. Typically, standard-definition refers to digital formats with pixel dimensions close to those of
analog TV standards, such as NTSC and PAL (around 480 or 576 vertical lines, respectively). The most common HD
formats have pixel dimensions of 1280x720 or 1920x1080, with a widescreen aspect ratio of 16:9.
HD video formats include interlaced and noninterlaced varieties. Typically, the highest-resolution formats are
interlaced at the higher frame rates, because noninterlaced video at these pixel dimensions would require a
prohibitively high data rate.
You can reap benefits from shooting and editing in high-definition formats even if you output to standard definition.
For example, the quality of high-definition clips remains high when you zoom into them or pan across them in the
context of standard-definition projects.
HD video formats are designated by their vertical pixel dimensions, scan mode, and frame or field rate (depending on
the scan mode). For example, 1080i60 denotes interlaced scanning of 60 interlaced 1920x1080 fields per second,
whereas 720p30 denotes progressive scanning of 30 noninterlaced 1280x720 frames per second. In both cases, the
frame rate is approximately 30 frames per second.
David Van Brink shows an excellent example on his omino pixel blog of why shooting in a high-definition format is
useful even for standard-definition delivery, because the extra pixels give you a lot of room for synthetic (fake) camera
work, such as zooms and pans in post-production.
Frame Hold Time Remap property
Motion or Opacity values and
keyframes Transform property values and
keyframes Keyframe type—Bezier, Auto Bezier,
Continuous Bezier, or Hold—is retained.
Sequence marker Markers on a new solid-color layer To copy sequence markers, you must
either copy the sequence itself or import
the entire Adobe Premiere Pro project as a
composition.
Speed property Time Stretch property Speed and time stretch have an inverse
relationship. For example, 50% speed in
Adobe Premiere Pro is converted to 200%
stretch in After Effects.
Time Remapping effect Time Remap property
Titles Not converted
Universal counting leaders Not converted
Video and audio transitions Opacity keyframes (Cross dissolve
only) or solid-color layers
Video effect properties and
keyframes Effect properties and keyframes, if
the effect also exists in After Effects After Effects doesn’t display unsupported
effects in the Effect Controls panel.
Volume and Channel Volume
audio filters Stereo mixer effect Other audio filters are not converted.
Adobe Premiere Pro asset Converted to in After Effects Notes