I can´t change the playback range stop time on the animations, I tried changing the settings in a master sequence, but It doesn´t work either. How do I change this?
do you mean the duration of each track,
or just stop time for the whole animation?
I don’t think you can expand or shrink a bunch of tracks
together in the master sequence editor,
but you can create a new blank master sequence
and then drag the movie you want to modify into it,
so that you can change its “Time Scale” (as the playback speed)
and then manually alter the shots length or click “Auto Size”.