Apple Final Cut Pro 6 - Manual (Page 1480)

Chapter 30 Working with Mixed-Format Sequences 695
IV
Upconverting SD Video
Upconverting a 4:3 aspect ratio image to a 16:9 frame results in borders (or side panels)
on the left and right sides of the 4:3 image. This type of frame is sometimes referred to
as pillarboxed.
If the aspect ratios of the original and destination formats match (for example,
720 x 480 anamorphic footage upconverted to 1920 x 1080), you can simply scale
the original video to the destination size.
Pillarboxing 4:3 Video in a 16:9 Frame
Scaling 4:3 video to 16:9 results in black side panels on either side of the 4:3 image.
Original
size Original
aspect ratio Destination
size Destination
aspect ratio Upconversion
method
720 x 480 4:3 (1.33) 1280 x 720,
1920 x 1080 16:9 (1.78) Scale up
and pillarbox
720 x 480
(anamorphic) 16:9 (1.78)
squeezed 1280 x 720,
1920 x 1080 16:9 (1.78) Scale up
1280 x 720 16:9 (1.78) 1920 x 1080 16:9 (1.78) Scale up
480 to 720
480 to 1080
Side panels