if you press cntrl while tweeking x/y/z camera/projector on the timeline, you can control slope... at least in theory.
bye andraz On čet, 2006-05-25 at 16:08 +0930, Jonathan Woithe wrote: > Hi Nicolas > > > I use keyframes and the compositor window to create a vertical scrolling > > (end credits) from a still picture. However, the scrolling speed isn't > > constant. I assume that's due to the fact that interpolations between > > keyframes are made with a bezier curve. > > You are correct; the bezier curves used are forced to have zero slope > at every keyframe. This means you get "smooth" starting. While this > can be good in certain circumstances it is a pain for others such as the > credit example you mention. At times you do want keyframe interpolation > to use something else which produces constant speed between keyframes. > > > Is there a way to use a linear interpolation instead of the bezier > > curve? That way I would be able to scroll my end credit picture at a > > constant speed, wouldn't I ? > > With linear interpolation the speed would be constant, yes. > > This is actually an aspect to Cinelerra which I noticed with annoyance about > 18 months ago for the same reasons as you - I was scrolling credits and > noticed they were *much* slower at the start and end than in the middle. It > is most irritating. Unfortunately cinelerra (both vanilla and CVS/SVN) do > not have alternative curves available (at least not when I last checked > CVS/SVN about a year ago). I would offer to look into this myself but I am > currently far too busy with other FOSS projects and life in general. > > The workaround I came up with at the time is a bit fiddly but with patience > you can get reasonable results. I arranged things so that the approximately > linear portion of the bezier curve (ie: the bit in the middle) corresponded > with the part of the timeline where the credits were to scroll. For my > project this meant starting the scroll about 30 seconds before the credits > and ending it 30 seconds after the credits. The starting and ending Y > values were adjusted so that the credit graphic just became visible and just > finished at the appropriate points in the timeline. This last requirement > is where things get a bit fiddly - it's pretty much a trial-and-error thing. > > Assuming the credits are at the end of the movive, an unfortunate > consequence of this is that your final rendered movie has a blank, silent > portion tacked onto the end which lasts lasts for 30 seconds (or whatever > runout time you needed for the curve in your particular project). To avoid > this blank silent stuff at the end of the render the easiest thing to do is > to select from 0:00:00.000 to the point where the credits/movie material > ends and then choose File|Render. To select such a long timespan accurately > I find it best to type the times into the selection span boxes under the > timeline. > > I hope this helps. > > Regards > jonathan > > _______________________________________________ > Cinelerra mailing list > [email protected] > https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra _______________________________________________ Cinelerra mailing list [email protected] https://init.linpro.no/mailman/skolelinux.no/listinfo/cinelerra
