• Adobe After Effects Expressions

  real value to change comp duration

  Posted by Rainier Raydán on August 30, 2017 at 7:56 pm

  Hi guys! I’m working in a script to change the duration (and other things) of the or selected comps. The problem is that the value that I get when I use alert(selectedComps.duration) is very strange for me. In the timeline we can see fps and timecode (0:00:00:00) but the value I get from that alert is “x.yyy”, I can see that x is the amount in seconds of the composition but after “.” they are decimals that I cant figure it out how it works. I soupose is the fps divided by a number I dont know…

  I’m thinking in a text box to get the first number (seconds), do praseFloat() and get a real number. Also other box to get the frames and apply a math function to it. Do you guys knows any math function I can use?

  Thanks!

  Andrei Popa replied 8 years, 8 months ago 2 Members · 7 Replies
• 7 Replies

• 

  Andrei Popa

  August 31, 2017 at 8:10 am

  var compLength = selectedComps.duration;
var minutes = Math.floor(compLength / 60);
var seconds = Math.floor(compLength % 60);
var frames = Math.round((compLength - Math.floor(compLength))/selectedComps.frameDuration);
alert (minutes +":"+ seconds +":"+ frames);

  I don’t know if it works with multiple selected comps.

  Andrei
• 

  Rainier Raydán

  August 31, 2017 at 1:36 pm

  Nice! Thanks Andrei!

  But I need to change the duration of the comp with this values

  I want to set the minutes, the seconds and the number of frames with this UI but I dont know how!
• 

  Andrei Popa

  August 31, 2017 at 6:20 pm

  You just reverse the process. Lets say the variables for the texts of this GUI are sec,min,fps,frames.

  min*60 + sec + frames/fps

  Andrei
• 

  Rainier Raydán

  September 1, 2017 at 8:29 pm

  Ok I have this
  
var compLength = app.project.activeItem.duration;
var minutes =2
var seconds = 15
var frames = 20;

  minSec = (minutes*60)+seconds;

  realFrames = frames /app.project.activeItem.frameDuration;

  finalDuration = parseFloat (minSec +"."+realFrames);

  app.project.activeItem.duration = finalDuration;


  But the comp duration still wrong. It has to be 02:15:20 (it’s a 25 frames comp) but the script result is 02:15:13…
• 

  Andrei Popa

  September 2, 2017 at 6:09 am

  That is because you used frameDuration instead of fps. Fps is 1/frameDuration, which makes your realFrames value frames*app.project.activeItem.frameDuration. The script would be like this
  var compLength = app.project.activeItem.duration;
var minutes =2
var seconds = 15
var frames = 20;

  minSec = (minutes*60)+seconds;

  realFrames = frames *app.project.activeItem.frameDuration;

  finalDuration = minSec +realFrames;

  app.project.activeItem.duration = finalDuration;

  Andrei
• 

  Rainier Raydán

  September 3, 2017 at 12:44 pm

  Wow! That help! It worked just fine but when the comp is 23.976 fps it doesnt work… when the minutes value its greater thant 0 the results in frame and in seconds doesnt match… minutes = 1, secondes = 10 and frames = 5 and the result is 0:01:10:03…
• 

  Andrei Popa

  September 4, 2017 at 6:51 am

  It seems that there is a problem with this framerate. Even if you put an integer as the duration, you get some frames.

  Andrei

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