7. Reuse a scene style across source files

The edit applies the same kind of zoom in two places with different amounts. You will extract that familiar operation behind a small callable interface, then use it twice without changing the rendered result.

Continue in the same project. Use learning.clipasm from Change a named scene after assembly.

1. Create the program directory

Create a programs directory.

2. Define the reusable operation

Create programs/scene_motion.clipasm:

clipasm 1

input video: Video
param by: Number = 4%

zoom_in($video, $by)

This source file defines one program. input video declares its Video input, and param by declares a Number parameter with a default. Its final Video returns to the caller.

3. Import the program

In learning.clipasm, add the import after config and before the clip declarations:

import "programs/scene_motion.clipasm" as scene_motion

The path is relative to the file containing the import. scene_motion is the local call name.

4. Replace the meadow operation

In the meadow clip, replace:

zoom_in(4%)

with:

scene_motion

The omitted by parameter uses the program’s 4% default.

5. Replace the evening operation

Inside the final during body, replace zoom_in(2%) with:

scene_motion(2%)

This call overrides the default for the subtler evening movement. Each call consumes the nearest Video from its current stack and passes it into a separate invocation of scene_motion.

6. Validate the complete source package

clipasm validate learning.clipasm

Validation checks both source files and still reports 108 frames.

7. Render the reusable program

clipasm render learning.clipasm

Rendering produces the same 4.5-second edit as before.

8. Change the shared style

In programs/scene_motion.clipasm, change the default:

param by: Number = 6%

9. Validate the style change

clipasm validate learning.clipasm

10. Render the style change

clipasm render learning.clipasm

11. Check the style change

The meadow now uses the stronger 6% default. The evening remains at its explicit 2% override. One interface controls the shared style without removing local choices.

Complete checkpoint

Your finished programs/scene_motion.clipasm should be:

clipasm 1

input video: Video
param by: Number = 6%

zoom_in($video, $by)

Your finished learning.clipasm should be:

clipasm 1

config {
    video {
        width = 320
        height = 180
        fps = 24
    }
    output = "generated/learning.mp4"
}

import "programs/scene_motion.clipasm" as scene_motion

clip {
    image("assets/morning.png", 1500ms, contain)
} as morning

clip {
    image("assets/meadow.png", 1500ms, contain)
    scene_motion
} as meadow

clip {
    image("assets/evening.png", 1500ms, contain)
} as evening

clip {
    $morning
    $meadow
    flash_cut(200ms)
    $evening
} as edit

$edit
during($edit::evening) {
    scene_motion(2%)
}

You have now developed one project through stack composition, named clips, transforms, and a transition. You also used placement-based editing and an imported source program.

Continue with the How-to guides when you have a specific task, or use the Language reference for exact rules.