[ankit-v2-3]

Summary

Stacked on #108 (LUT). Base will move to main automatically when #108 merges. Server side: Spext/streaming_service#76 (videodb-server needs no change, the timeline dict passes through).

• Motion(enter=None, exit=None, keyframes=None) → Clip(motion=...). Emitted only when set.
• MotionPreset(preset, duration=0.4, amount=0.08, easing=ease_out) with MotionPresetName: fade, slide_up/down/left/right, pop, wipe_left/right. Slides and pop include a fade; an exit runs the entrance backwards.
• Keyframe(time, value, easing=linear) on KeyframeProperty: offset.x, offset.y, scale, rotation (degrees, clockwise), opacity. Clip-relative times, easing on the destination keyframe, values replace the base and hold outside their range. Easing: linear, ease_in, ease_out, ease_in_out, back_out.
• Effect enum for the server's defined set: zoom_in, shake, zoom_out, ken_burns, pulse. Clip.effect still accepts a plain string.
• Light client-side validation (ranges, unknown property, non-increasing times); the full rules (not on audio/caption, exclusive with effect, exclusive with a transition side, fits the clip, 32 keyframes max) are enforced by the service with a public error.

from videodb.editor import Motion, MotionPreset, Keyframe, KeyframeProperty, Easing, Effect

clip = Clip(asset=TextAsset(text="Hello"), duration=4,
            motion=Motion(enter=MotionPreset("slide_up", duration=0.5),
                          exit=MotionPreset("fade", duration=0.3)))

logo = Clip(asset=ImageAsset(id=image.id), duration=6, fit=None, position=Position.top_right,
            motion=Motion(keyframes={KeyframeProperty.scale: [Keyframe(0, 0.6), Keyframe(0.6, 1, Easing.back_out)],
                                     KeyframeProperty.opacity: [Keyframe(0, 0), Keyframe(0.4, 1)]}))

broll = Clip(asset=VideoAsset(id=video.id), duration=8, effect=Effect.ken_burns)

Docstring notes the text-layer caveat: text is drawn on a canvas-sized layer, so scale/rotation act about the canvas centre unless TextAsset.width/height is set.

Test plan

• pytest — 22 passed (11 new in tests/test_editor_motion.py)
• Against a dev deployment of Spext/streaming_service#76: generate_stream() with a slide_up/fade text clip, a keyframed logo and a ken_burns clip

🤖 Generated with Claude Code

[ankit-v2-3]

Folded into #110 (single SDK PR for LUT + motion, base main).