Manipulating Time

Manipulating Time

 

1. Freeze Frame
   1. Right-click a layer, select “Time->Freeze Frame”
   2. You’ll notice a weird new keyframe for an also new “Time Remap” property (described more below.) For now you can ignore that keyframe.
2. Slowing Down and Speeding Things Up
   1. Time Stretch
   2. Right-click a layer, select “Time->Time Stretch…”
   3. This is more like a per-layer setting, as opposed to a property that you can animate or see in the twirled-down areas. This setting can be displayed with UI toggles at the bottom-left of AE.
3. Time Remapping – aka “keyframing the timecode of a layer”
   1. Sometimes you’ll want to do something fancier with the playback speed of a layer. For example, maybe you’ll want playback to get faster and faster over time, or slower and slower, or some combo, or perform a gradual slow-mo reverse that ends with a freeze-frame, etc. Time remapping is handy in these more complex cases.
   2. After enabling Time Remapping, a new property is added to the layer called Time Remap.
   3. This Time Remap property will automatically have two (2) new keyframes added: One at the initial In point of the layer, and one at the initial Out point of the layer (plus one frame.)

      

      

   4. The layer’s In and Out boundaries can now be extended beyond their initial minimum and maximum positions. I.e., the layer can be lengthened indefinitely.
      
      
   5. The timeline can display timecode or frame count. You can quickly switch back and forth by Command-clicking the time display in the top-left of the timeline panel:
      
      Note that the values of the time-remapping property change to reflect the current viewing choice. For now, let’s switch to the frame count view.
   6. When working with time-remapping, it can sometimes help to imagine that each frame of the original, non-time-remapped layer being numbered 0000, 0001, 0002, 0003, etc.

      

   7. The keyframes of the Time Remap property indicate what frame number should be happening at that particular point in time. After Effects will “tween” or interpolate what frames should be displayed between the keyframes. (This is why the initial two keyframes are set at the beginning and end, and their values are 0000 and whatever the last frame number is.)
   8. Time Remap keyframes are little diamonds at first (values change at constant rate) but can be set to Ease-In or Ease-Out or Hold or any other variation. This allows for time to speed up or slow down gradually.
   9. By default, AE will take a very simple approach to interpolating in-between frames of a time remapped layer. You can use Frame Blending to improve the results.
      
      Frame Blending has a per-layer switch, as well as a global switch. They must both be turned on to see the desired result. The per-layer switch will only be available on video sources (not sub-comps.) You must go into the sub-comp and turn on the frame-blending switch.
   10. Freeze Frame is actually a special case of Time Remap, where a “hold” keyframe (looks like a block) is set with a specific time value.
4. Looping the Time of Material
   1. Simplest in some cases: Loop an Imported Video n Times
      1. Right-click on imported item and select “Interpret Footage->Main…”
      2. Enter a value other than zero in the Loop text box and click OK
   2. Loop with Expressions (for looping keyframes)
      1. Typical examples:
         • loopOut( “cycle” ), loopOut( “pingPong” )
         • loopOut( “continue” ) – After running out of keyframes, try and extrapolate what would happen if the property kept progressing based on when the keyframes ran out
      2. loopOutDuration – Allows the loop to be shorter than the span of looped keyframes
         • Example: loopOutDuration( “pingPong”, 1.5 )
           Means: After running out of keyframes, loop the last 1.5 seconds of the keyframes.