“Time trim” is one of four layer rules in Templater’s Time Sculpting feature, and it is the one that moves a layer’s In-Point and Out-Point to line up with a sibling layer. It is not the same thing as time cropping, which sets the length of the whole composition, and it is not time shifting or time stretching. The words sound alike, and all four are covered under the Time Sculpting heading in our documentation. This page sorts them out.
We build Templater. Here is the plain version. Each of the four rules answers a different question about footage that changes length from one row of your data to the next.
Why the timeline needs rules at all
A normal After Effects template has a fixed timeline. The intro runs for a set number of frames. The main clip sits after it. The outro card sits after that. Every layer has an In-Point and an Out-Point, and you placed them by hand.
That works when every version of the video uses the same footage length. It breaks when the footage changes. Say you are making a batch of videos from a spreadsheet, and one column points to a clip. Row one has a short clip. Row two has a much longer one. Your hand-placed Out-Point on the clip layer is now wrong for both. The short clip leaves dead air. The long one runs into the outro card or gets cut off.
Time Sculpting is our answer to that. In our words, it is a method for making After Effects composition timelines dynamic. You configure layers with time-based rules that account for differences in source durations when Templater processes your data. Templater then preserves layer timing and the overall duration of the composition. As layers get updated, it can adjust the duration of a composition if needed.
One setup requirement applies to all four rules. You must set a target composition to use any of the Time Sculpting features. If a rule seems to do nothing, check that first.
The four rules are crop, trim, shift and stretch. We will cover each one. Trimming gets the most room here, because it is the subject of this page.
Time trim: where a layer starts and stops
Time trimming lets Templater automatically control where a layer’s In-Point and Out-Point should move to along the timeline. The key idea is the target. For each layer you want to trim, you pick a sibling layer as its In-Point target, its Out-Point target, or both.
The In-Point target dictates where the layer’s In-Point trims to. The Out-Point target dictates where the Out-Point of the layer trims to. You can trim both ends. You can trim the In-Point without touching the Out-Point. You can trim the Out-Point without touching the In-Point. Each end is its own choice.
The documentation gives four settings, and they are easy to read as a grid:
- The layer’s In-Point trims to the In-Point of the In-Point trim target.
- The layer’s In-Point trims to the Out-Point of the In-Point trim target.
- The layer’s Out-Point trims to the In-Point of the Out-Point trim target.
- The layer’s Out-Point trims to the Out-Point of the Out-Point trim target.
So a trim is always “my edge goes to your edge.” You choose which of your edges, and which of the target’s edges. That is the whole concept.
Trimming moves an edge, and speed is a stretch setting
Trimming moves a layer’s In-Point or Out-Point. Our documentation describes playback speed changes under time stretching, not under trimming. As a general way to picture it, pulling an Out-Point back shortens what shows at the end of the layer, and moving an In-Point forward shortens what shows at the start.
Trimming also has Preserve settings. To preserve the beginning of a footage source, you select Preserve Beginning. To preserve the end, you select Preserve Ending. To preserve the full duration of a footage source, you select both.
Think about what each choice protects. Preserve Beginning says “the first frames of this clip must show.” Preserve Ending says “the last frames must show.” That can matter when the first frame is a title or the last frame is a logo. Choose the one that protects the part your viewer must not miss.
There is also overlap. You can overlap layers by a certain number of frames as they trim to their In-Point or Out-Point targets. If you want a clip to start a few frames before the previous one ends, for a crossfade for example, the overlap setting is where you say so.
Our docs add a caution that we want to repeat. If your source footage durations vary widely from one iteration to the next, you may need a combination of time trimming, time stretching and time shifting to make sure the beginning or end of a footage source is visible. Trimming alone is not a promise that a very short clip and a very long clip will both look right. Plan for the extremes in your data, not just the average.
The other three rules, in plain terms
Once trim is clear, the other three are easier. Each one answers a different question.
Time cropping: how long is the whole composition?
Time cropping marks temporal boundaries to dynamically adjust the duration of a composition. Reach for it when at least one footage layer has variable duration and you want the composition to follow.
The difference from trim is the object. Trim moves the edges of a layer. Cropping moves the edges of the composition. You use the In-Point of any layer to mark where the composition begins. You use the Out-Point of any layer to mark where it ends. Those can be on the same layer or on different layers. Use only one In-Point and one Out-Point for cropping.
The documentation shows four outcomes. The composition can crop so that it starts at the In-Point of a footage layer. It can crop so that it ends at the Out-Point of a footage layer. It can crop to both the In-Point and the Out-Point of the footage layer. Or it can crop to the In-Point of a footage layer and the Out-Point of a different layer in the composition.
Nesting is covered. You can create nested compositions that have dynamic durations. Templater adjusts the duration of any composition with time cropping applied, no matter how deeply nested it is in the project.
Time shifting: move the layer, keep its length
When you shift a layer, all its properties move in time by the same amount and in the same direction. The layer slides along the timeline.
You specify a sibling layer as the shift target. Then you choose to shift the layer by its In-Point or by its Out-Point until it reaches the same time as the target’s In-Point or Out-Point. Overlap is available here too. You can overlap layers by a specified number of frames as they shift in relationship to each other.
A good way to remember it: shift is what you use when the length of a layer is right but the position is wrong.
Time stretching: change the speed to fit
Templater can automatically stretch or compress a layer’s duration in the timeline by adjusting its playback speed. You might want this when you set aside a time period for a layer and you want footage sources of varying durations to fit exactly into that period.
Because stretching adjusts playback speed, the footage will speed up or slow down in the final rendered video. That is the honest trade-off. Stretching is meant to make footage fit a period exactly, and the footage will play faster or slower to do it. A layer stretches to the In-Point of its target, to the Out-Point of its target, or to the end of its containing composition. A layer always stretches from its In-Point.
The four side by side
- Crop: sets where the composition starts and ends. The object is the composition.
- Trim: moves a layer’s In-Point and Out-Point to a target. Speed changes belong to stretch.
- Shift: slides the whole layer, moving its properties in time together.
- Stretch: fits a layer to a space by changing its playback speed.
Four Time Rules
Each rule acts on a different object
| Rule | Acts on | Leaves alone |
|---|---|---|
| Crop | The composition’s start and end | Layer edges and speed |
| Trim | A layer’s In-Point and Out-Point | Playback speed |
| Shift | The layer’s position in time | Length and speed |
| Stretch | Playback speed | Layer position |
If you only remember one thing from this page, remember the object each one acts on and what it leaves alone. Crop acts on the composition. Trim acts on the layer’s edges. Shift acts on position. Stretch acts on speed.
A worked example, and how to check it
Here is a scenario. It is an illustration we made up, not a customer story. A producer has a template with three parts: an intro card, a customer-supplied clip in the middle, and an outro card with a logo. The spreadsheet has one row per video, and a column holds the path to each customer’s clip. The clips differ in length.
The producer wants three outcomes. The intro stays fixed. The outro card should begin right where the clip ends. The composition should end when the outro finishes.
Map those wishes to the four rules:
- Clip layer: its length follows its footage, so no rule is needed on the clip itself. It sits after the intro.
- Outro layer: time shifting fits this need. The outro’s In-Point shifts to align with the Out-Point of the clip layer, which is the shift target. It moves to wherever the clip ended for that row.
- Composition: time cropping handles this. The composition crops to end at the Out-Point of the outro layer. A long clip makes a long video, and a short clip makes a short one.
Where does trim come in? Suppose the producer also has a background music bed or a lower-third graphic that must start when the clip starts and stop when it stops. Trim fits that. The lower third’s In-Point trims to the In-Point of the clip layer. Its Out-Point trims to the Out-Point of the clip layer. Now the graphic is exactly as long as the clip on screen, for every row. If the end of the graphic must show, look at the Preserve settings.
That last point is the reason to pick trim over stretch. A lower third that speeds up or slows down to match a clip may look wrong, while one that is simply started and stopped with the clip may look fine. The choice between trim and stretch is a design choice, and no setting can make it for you.
Set up crop in a few steps
Our how-to for auto-adjusting composition duration is short. It goes like this:
- Apply the Templater Settings Effect to a layer.
- In the Effect Controls, in the Time section, check the Comp Starts at In-Point box.
- Set the In-Point of the layer in the timeline. That point is where its containing composition begins.
- Create another layer in the composition and apply the Templater Settings Effect to it.
- In the Time section of its Effect Controls, check the Comp Ends at Out-Point box.
- Set the Out-Point of that layer. That point is where the composition ends.
You can also set both points with one dynamic layer. As the footage duration of the layer updates during Templater’s processing, the In-Point and Out-Point adjust dynamically. We do not recommend more than two layers for specifying the In-Point and Out-Point for time cropping. More than two layers can give unexpected results.
Crop Setup
Set up auto-adjusting composition duration
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Apply the Templater Settings EffectApply the Templater Settings Effect to a layer.
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Check Comp Starts at In-PointIn the Effect Controls, in the Time section, check the Comp Starts at In-Point box.
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Set the layer’s In-PointSet the In-Point of the layer in the timeline.
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Create another layerCreate another layer in the composition and apply the Templater Settings Effect to it.
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Check Comp Ends at Out-PointIn the Time section of its Effect Controls, check the Comp Ends at Out-Point box.
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Set the Out-PointSet the Out-Point of that layer.
For the full walkthrough of the crop setup, see our post on how to make an After Effects comp match its content length automatically. For the wider view of all four techniques, see Time Sculpting with Dataclay Templater.
Check the result before you render the batch
Time rules are easy to get subtly wrong, so look at them before a big run. Our documentation describes Spot Checking as a way to quality assure batch render or replication processes, so you can quickly see how data merges across many jobs.
As general practice, pick rows from the extremes of your data: the row with the shortest footage and the row with the longest. Our post on preview modes and spot checks explains how to run these checks. If your footage can go missing or come from a remote location, read how Templater handles missing and remote footage as well, because what a layer follows depends on which footage ends up in the row.
Bottom line
Use time trim when a layer’s start or end should follow another layer. Use time cropping when the whole composition’s length should follow your footage. Use shift to move a layer without changing it, and stretch to fit a layer into a space by changing its speed. Set a target composition first, test with your shortest and longest footage, and combine rules when the durations in your data vary widely.
If you are weighing whether to build this into a larger pipeline, our guide to After Effects templates for batch rendering covers the wider design. The full set of Templater articles is on our Learn page.
Here are answers to common questions about time trim and the terms around it.
Frequently Asked Questions
What is the difference between time trim and time cropping in Templater?
Trim acts on a layer. It moves that layer’s In-Point and Out-Point to line up with a sibling layer you name as the target. Cropping acts on the composition. It uses the In-Point and Out-Point of layers to mark where the composition begins and ends, so the whole composition gets longer or shorter. If you want a lower third to match a clip, use trim. If you want the finished video to end when the footage ends, use cropping.
Does time trim change how fast my footage plays?
Trimming moves the In-Point and Out-Point of a layer. Our documentation describes playback speed changes under time stretching, which adjusts playback speed so a layer fits a space exactly. If you need footage to fill a set slot and a speed change is acceptable, use stretch. If speed must stay natural, trim or shift are the rules to look at.
How do I keep the start or end of a clip from being cut?
Use the Preserve settings. Select Preserve Beginning to protect the start of a footage source, Preserve Ending to protect the end, or both to preserve the full duration. Our documentation also says that when source durations vary widely between iterations, you may need to combine trimming with stretching or shifting so the start or end of a footage source stays visible. Test with your shortest and longest clips.
Why do the time rules do nothing in my project?
Check that you have set a target composition. Our documentation states that you must set a target composition to use any of the Time Sculpting features, and that applies to cropping, trimming, shifting and stretching alike. Then confirm each trimmed or shifted layer has a sibling layer chosen as its target, since the rules move a layer in relation to a target.
Can I trim only the start of a layer and leave the end alone?
Yes. You can trim both the In-Point and the Out-Point of a layer, trim the In-Point without trimming the Out-Point, or trim the Out-Point without trimming the In-Point. Each end has its own target setting. You can also overlap layers by a number of frames as they trim to their targets, which helps when you want one layer to begin slightly before another ends.
How many layers should I use to set the crop points?
Use one In-Point and one Out-Point, either on two layers or on a single dynamic layer. As the footage duration of that layer updates during Templater’s processing, the points adjust. We do not recommend using more than two layers to specify them, because more than two can give unexpected results. The setup uses the Comp Starts at In-Point and Comp Ends at Out-Point boxes in the Time section of the Templater Settings Effect.
Do time rules work inside nested compositions?
Cropping does. Templater adjusts the duration of any composition with time cropping applied, no matter how deeply nested it is in the project. Remember that a target composition must still be set for the Time Sculpting features to work.
