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A clip’s asset sets what it plays. Four asset types read a file from a URL. Timing, placement and effects work the same for all four. src is an https URL, or the URL of a file you uploaded to Rendobar. Text, timers, subtitles, shapes and nested timelines are clips without a file, each on its own page.

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Video

volume is linear gain: 1 keeps the source level and 0 mutes it. Keyframe it to duck music under a voice. See Audio and mixing.

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Images

An image shows one frame for the clip’s length. A still with no motion looks like a mistake, so add a slow push-in: keyframe transform.scale from 1 to about 1.15 across the clip. See Keyframes and easing.

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Audio

An audio clip has no picture. Put music on its own track under the footage and set its level with volume. fadeIn and fadeOut fade it in from silence and out to silence, in seconds. See Audio and mixing for levels, ducking and sound effects.

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Lottie animations

An animation plays a Lottie .json file, as exported by After Effects, Figma or LottieFiles, with a transparent background. It plays once, for its own length. Place and size it with transform, like an image.
Export the file self-contained. The API refuses a file that loads images or fonts from elsewhere, because the render only gets files through a checked download.

a Lottie lower third sweeping in, its words a compose text clip

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Using part of a source

trim picks which seconds of the source fill the clip. { "from": 4, "to": 9 } plays seconds 4 to 9 of the file. length sets how long the clip lasts on the timeline. Without trim, the clip plays from the start of the source.

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Speed

speed plays a clip faster or slower. 2 is double speed and 0.5 is slow motion. At double speed a clip lasts half as long, and its sound changes pitch.

before

speed 2

Shapes, nested timelines and Lottie animations do not accept speed. The first two have no file to speed up, and a Lottie plays at its own frame rate. Avoid slow motion on the outgoing clip of a transition, as it can run out of frames before the transition ends.

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Opacity

opacity runs from 0 (invisible) to 1 (solid). Keyframe it to fade a clip in or out.

before

opacity 0.45

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Blend modes

blendMode sets how a clip mixes with the layers below, for example a light leak or texture over footage. It only works on a clip above another track.
The video, image, audio and animation references list every asset field. Clip fields are in the timeline reference.
Last modified on October 20, 2026