• Adobe After Effects

  remove frames

  Posted by Alex Harding on November 15, 2006 at 4:35 pm

  hithere

  im doing some stuff with some downloaded archive footage
  at some point some kind of frame rate conversion has already been applied to the footage because every 4th frame is doubled up.

  what is the best way to remove all the doubled frames (ie, every 5th frame)? I’m not bothered about how this will affect the playback speed / audio synching, i just want the motion to be smooth.

  cheers,
  alex

  Ze’ev Gilad replied 14 years ago 5 Members · 6 Replies
• 6 Replies

• 

  Alex Harding

  November 15, 2006 at 5:51 pm

  is there anyway to automate it? the clip is about 20 minutes long
• 

  Chris Smith

  November 15, 2006 at 5:53 pm

  It’s probably some sort of pulldown that was done to it. You can try using the standard AE pulldown removel process. But if the cadence is non-standard, AE may not recognise it but it’s worth a try. Check the manual on “Remove pulldown”.

  Chris Smith
  https://www.sugarfilmproduction.com
• 

  Steve Roberts

  November 15, 2006 at 6:09 pm

  If pulldown doesn’t work, you may be able to apply time remapping, keyframe it to skip the fifth frame, then apply a loop_out expression, replacing “cycle” with “continue” so the pattern continues through the clip. But it’s not for the faint-of-heart.

  You may also consider rendering to a sequence, then deleting every fifth image in the finder/windows explorer. That’s not as hard as it seems — try arranging the list so the fifth, tenth, fifteenth (etc.) images appear in the same column so you can find them faster. Once that’s done, you re-import the sequence, choosing “force alphabetical order” so it becomes 1,2,3,4,6,7,8,9,11,12,13,14 …

  Anybody else?
• 

  Dan Ebberts

  November 15, 2006 at 6:10 pm

  If you really want to remove every 5th frame, you could use a Time Remapping expression like this:

  n = 5; // skip every nth frame
  frameToSkip = 4; // 0,1,2 …n-1
  currFrame = timeToFrames(time);
  currFrame += Math.floor((currFrame – frameToSkip)/(n-1)) + 1;
  framesToTime(currFrame)

  The way it’s set up above, it will skip the 5th frame of each group of 5. If you wanted it to skip the first frame of each group, for example, you would change frameToSkip to 0.

  Dan
• 

  Alex Harding

  November 15, 2006 at 7:00 pm

  thanks very much dan,
  that is excedingly useful.
• 

  Ze’ev Gilad

  April 13, 2012 at 7:53 pm

  This is exactly the function I need; but this expression doesn’t work for me as expected.

  I need to “remove” every 6th frame; I’m trying to get just these frames:
  01 02 03 04 05 07 08 09 10 11 13 …
  (remove 00 06 12… could also remove 01 07 13; they’re duplicates)

  But these expression, with n=6 and frameToSkip=0 gives me:
  01 11 21 31 41

  In other words, it plays at 10x speed.

  Am I missing something?

  (I’m trying to “de-convert” NTSC back to PAL — every 6th frame is duplicated. Speeding up doesn’t work, because it skips the wrong frames.)

  Thanks!

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