is trim adding a frame?

[Naked Misty]

Can someone please explain why this happens, is it a bug or just the way it is? Take this simple script as an example.

avisource=("c:\movie.avi")
trim(200,2200)
showframenumber

Simple right, 2200 - 200 = 2000 total frames. Why does this script show a total of 2001 frames when viewed in virtualdub. With the "showframenuber" showing 0 thru 2000 which is 2001 frames, when is should be showing 0 thru 1999 being the 2000 frames I wanted. Whats going on?

[Wilbert]

First your script should be


avisource("c:\movie.avi")
trim(200,2200)
showframenumber


second

Simple right, 2200 - 200 = 2000 total frames. Why does this script show a total of 2001 frames when viewed in virtualdub.
Because that script has 2001 frames, namely: 200, 201, ..., 2200 (see docs).

[stickboy]

Originally posted by Naked Misty
Simple right, 2200 - 200 = 2000 total frames.Nope. It's 2200 - 200 + 1 because Trim's endpoints are inclusive.

If you'd prefer to get the range [start, end) instead of [start, end], try my Trim2 function (especially if you're using Trim in your own user-defined functions (http://forum.doom9.org/showthread.php?s=&threadid=58358)).

[Naked Misty]

Thanks for the replies guys and to Wilbert for pointing out my typo in my script. It's still confusing and the reason I'm bringing this up is because as stickyboy mentioned I have been using it in a function.

function combofade( int "duration1", int "duration2" )
{
duration1 = default( duration1, 0 )
duration2 = default( duration2, 0 )

total = (trim2 - trim1) + 1
end = (total / 2)
round(end)
lenght = (total * 2)
start = (end + 1) + total

fadein1(duration1)+fadeout1(duration2)

equal = trim(0,end)+trim(start,lenght)

trim(0,end)+trim(start,lenght)

framecount == total ? equal : blackness.subtitle("error in combofade")
}

Note: line total, I have to add one frame so the frame numbers match the original clip and audio sync will be kept. I could be doing it the hard way but that's how I learned.

[stickboy]

You really should use Trim2 instead, for all the various reasons I explained in that thread.