Hi NADWW
There is a slight difference (a VERY slight difference :-) ) but not enough to be noticable...
e.g. A centrally placed line of size 10 text (ABCDEFG) in a 5 second text image.....
Time to scroll using automatic scrolling (appearence - disppearance) = 4.6 seconds
Time to scroll using position( -100 -+100 appearence - disppearance) = 2.6 seconds
Time to scroll using Position (-52 to +52 appearence - disppearance) = 5.0 seconds
Automatic scrolling starts just outside the frame (0.2 seconds above and 0.2 seconds below.)
Position scrolling using keyframes using a full screen displacement (100% out above and 100% out below) means the text crosses the screen faster. In this case about twice as fast. This is logical as about 1/2 the screen has to scroll before the text actually appears.
Using Position keyframe scrolling with the text starting just off the frame at start and ending just off the frame at end gives almost exactly the same time as the automatic scrolling.
In practice you can't make it slower this way. The text clip must be extended if a significant difference is required.
Nat