Animations
Shotstack provides a comprehensive system for creating smooth transitions (known as tweening) between keyframes in your video clips.
Tweening with Shotstack
Shotstack's tweening framework allows developers to create animations by specifying how properties change over time. The core of this system is the use of arrays to define animation keyframes.
Instead of using a single start and end point, developers can create complex animations by defining multiple keyframe
segments for a given property. Each segment specifies a start value (the initial state), end value (the final state),
start time (when the animation starts), duration (how long the animation lasts), and interpolation method (how the values
transition from start to end).
This approach enables the creation of nuanced, multi-stage animations for properties such as position and scale, all within a straightforward, array-based structure.
We currently support tweening for the following properties:
- Opacity: Animate the transparency of a clip.
- Offset: Control the x and y position of a clip.
- Rotation: Animate the rotation of a clip
- Skew: Control the horizontal and vertical shearing effect
- Volume: Animate the audio volume of a clip.
Animating a single property
You can animate movement by adding an array with tweening properties to the property you wish to animate.
Animate position
{
"timeline": {
"tracks": [
{
"clips": [
{
"asset": {
"type": "image",
"src": "https://shotstack-assets.s3.amazonaws.com/logos/shotstack/small/icon.png"
},
"start": 0,
"length": 5,
"fit": "none",
"offset": {
"x": [
{
"from": -1,
"to": 0,
"start": 0,
"length": 2.5
}
],
"y": [
{
"from": 0,
"to": 1,
"start": 2.5,
"length": 2.5
}
]
}
}
]
}
]
},
"output": {
"format": "mp4",
"size": {
"width": 1280,
"height": 720
}
}
}
Animate multiple properties
You can add multiple tweening combinations to create complex animations.
{
"timeline": {
"tracks": [
{
"clips": [
{
"asset": {
"type": "image",
"src": "https://shotstack-assets.s3.amazonaws.com/logos/shotstack/small/icon.png"
},
"start": 0,
"length": 5,
"fit": "none",
"opacity": [
{
"from": 0,
"to": 1,
"start": 0,
"length": 5
}
],
"offset": {
"x": [
{
"from": -1,
"to": 0,
"start": 0,
"length": 2.5
}
],
"y": [
{
"from": 0,
"to": 1,
"start": 2.5,
"length": 2.5
}
]
},
"transform": {
"rotate": {
"angle": [
{
"from": 0,
"to": 360,
"start": 0,
"length": 2.5
},
{
"from": 360,
"to": 0,
"start": 2.5,
"length": 2.5
}
]
}
}
}
]
}
]
},
"output": {
"format": "mp4",
"size": {
"width": 1280,
"height": 720
}
}
}
Interpolation methods
The default interpolation method is linear, producing a constant rate of change. For more complex effects, you can use a bezier curve with easings.
{
"output": {
"format": "mp4",
"fps": 60,
"size": {
"width": 1280,
"height": 720
}
},
"timeline": {
"tracks": [
{
"clips": [
{
"start": 0,
"length": 5,
"fit": "none",
"asset": {
"type": "image",
"src": "https://shotstack-assets.s3.amazonaws.com/logos/shotstack/small/icon.png"
},
"offset": {
"x": [
{
"start": 0,
"length": 2.5,
"from": -1,
"interpolation": "bezier",
"to": 0,
"easing": "easeInOutQuart"
}
],
"y": [
{
"start": 2.5,
"length": 2.5,
"from": 0,
"interpolation": "bezier",
"to": 1,
"easing": "easeInOutQuart"
}
]
}
}
]
}
]
}
}
Easings
The easings available are:
| Easing Type | Description |
|---|---|
ease | Smooth transition with a gradual acceleration and deceleration. |
easeIn | Starts slowly, then speeds up. |
easeOut | Starts quickly, then slows down. |
easeInOut | Starts and ends slowly, with a faster middle section. |
easeInQuad | Speeds up at a steady rate from the start. |
easeOutQuad | Slows down steadily towards the end. |
easeInOutQuad | Gradual speed up, then gradual slow down. |
easeInCubic | Accelerates faster than easeInQuad, for a stronger start. |
easeOutCubic | Decelerates faster than easeOutQuad, for a stronger finish. |
easeInOutCubic | Strong acceleration at the start, smooth middle, strong deceleration at the end. |
easeInQuart | Even stronger acceleration at the start, for a very quick takeoff. |
easeOutQuart | Even stronger deceleration at the end, for a very smooth stop. |
easeInOutQuart | Quick start, steady middle, smooth stop. |
easeInQuint | Extremely fast start, used for dramatic effects. |
easeOutQuint | Extremely smooth stop, used for dramatic effects. |
easeInOutQuint | Very fast start and very smooth stop. |
easeInSine | Gentle acceleration, like easing into a swing. |
easeOutSine | Gentle deceleration, like easing out of a swing. |
easeInOutSine | Gentle start and end, like a smooth pendulum swing. |
easeInExpo | Starts slowly but speeds up dramatically, like an explosion. |
easeOutExpo | Starts fast then slows down dramatically, like something settling. |
easeInOutExpo | Starts and ends dramatically, for a very dynamic effect. |
easeInCirc | Starts slow and curves quickly into motion, like rolling a ball. |
easeOutCirc | Starts quickly and slows down in a circular motion, like a ball stopping. |
easeInOutCirc | Curves into motion, speeds up, then curves to a stop. |
easeInBack | Starts by pulling back slightly before speeding up. |
easeOutBack | Overshoots the end slightly, then settles back. |
easeInOutBack | Pulls back at the start, speeds up, overshoots the end, then settles back. |