Fragment matching

This skill is a stage of the recreate-video use case. Before you act on a recreation, new or carried on at any stage, load recreate-video if it is not loaded: its flow says which stage you are at, what the user has agreed, and what to ask next. Then come back here for the stage's work.

Two laws:

1. Measure, don't guess. Every invented motion or timing has been wrong on its first render. Numbers come from the reference's pixels, through the tools, never from imagination.
2. One fragment at a time. Split the timeline into fragments and match each one against the reference until it holds, then move on. Never tune the whole clip at once.

What it can rebuild today: flat-background motion graphics (app and product promos: cards, bars, chips, chat, grids) and illustrated templates (photo or clip slots dressed with stickers, doodles and cut-out shapes). Live action, kinetic typography, particles, 3D and character animation are out of reach. Say so before building, rather than deliver a plausible-looking wrong recreation.

The tools here read only a hosted reference. Frames you grabbed yourself carry no reliable times, so nothing is timed from them.

Read this before you need it:

The loop

1. Split the reference. picsart_media_segment_shots with the source and the window t0/t1 returns fragments, each a hold (one arrangement holds still) or a transition (it changes), with a suggestedStep: how densely to look at it. Look at a still either side of every boundary with picsart_media_video_stills: merge a boundary where nothing visibly changes, split a slow change it missed. A transition is real content and needs the densest work, never a gap to skip. Name each fragment by what happens in it ("the hero card shrinks and docks onto the input bar", never "fragment 3"), and work them in timeline order.
2. Take the census. Stills of the fragment at its suggestedStep. List everything that is there, not only what moves: each element's box, its fill or accent colour, its text, its corner radius. Motion checks cannot see a missing icon, a wrong accent or absent text, and those are the differences people notice first. Per element, also record:
   • how it changes: a rigid move, video inside its box, a mask reveal, a fade or twinkle, a flap or bend, a small idle motion, or none;
   • its first and last visible time, read on stills either side, not guessed from the motion;
   • what it is tied to: the container it moves with, or the element that drives its reveal;
   • the sound it lands on, when one lands with it.
3. Measure every beat on its route (below) with the motion-tracking-from-video skill, and write the measured beat table before you build any motion: per beat, its start and end time, its start and end extent (position, scale, rotation), and the tracking result each number came from. A beat with no row is a beat you are about to guess. One agent measured a card's geometry on stills and invented its time: it built a 0.225 s, 15% shrink where the reference measures 1.40 s and 67%. The beat it tracked over time was the one it got right.
4. Choose what carries each motion before you write it. Elements that move because their container moves are one composition with the motion on it, never the same keyframes copied onto each member, which drift apart. A treatment that appears around an element in place is a look's fade, not a second layer. A reveal tied to a moving element takes its edge from that element's measured track, never from keyframes of its own.
5. Build the fragment as the scene-building-basics skill says, and check it as the quality-review skill says.
6. Check it against the reference (below). Fix, and check again, within the fix rounds picsart-video-rules allows. Then go on, and say what is still off.

One route per kind of change

Checking against the reference

Export your render of the fragment's window and compare it with the reference over the same window. Each check answers one question, and none of them alone says the fragment matches:

• Check every fragment as you build it, not the clip at the end: a fragment that is wrong is cheaper to fix before the next one is built on it.
• Look at the fragment's density, not a flat rate. On one clip a hold asked for a still every 0.42 s and the transition right after it for one every 0.045 s. A flat 8 per second oversamples the first 3.4 times and undersamples the second 2.8 times, and the transition is where recreations differ. fps: "auto" on picsart_media_flow_diff scores each fragment at its own density.
• Every inventory run reports one plate finding per side, scored 0. It is the census saying which background it measured and what it left out, not a defect: read it, never chase it.
• Numbers first, pictures second. A still reads to within dozens of pixels; a tracking result, a layout query or a diff is exact. Spend stills on choosing targets, on what a number cannot say, and on the final look.
• A mismatch is usually a beat measured too sparsely (track it again, denser), the wrong carrier (a fade covering a jump in pose that should be one continuous move), or something the scene format cannot do. Say the last plainly; never bury a workaround in the scene.

Rules that bite

• Never use the reference's own pixels as content. A crop of the reference's photo in a content slot, or a whole frame, makes the appearance check score near perfect while proving nothing: the check compares your render with that same reference. Fill content slots with the user's own assets, or plain stand-ins, and expect colour findings on their content. A recreation is a document that could be re-rendered with other photos. When an element is a masked view of a larger picture, build the picture and the mask. Decorations are the one exception: they may be cut from a template the user owns (below). Leave those out of the appearance score, since matching them proves nothing.
• Cutting a decoration out of the reference. A still one is a cropped still: picsart_media_video_stills at one time with crop set to its box, saved with picsart_drive_upload before it goes into a scene, since a still sheet is not kept. A still has no transparency, so over anything but a flat background it takes its background box with it, unless it goes through picsart_image_remove_bg, which charges. A moving one is the hosted reference on a media layer, cropped and masked to its box, and only over a flat background the recreation keeps: a mask cannot separate it from what is behind it, so over a content slot it would carry a moving patch of the original photo across the user's. There, redraw it as shape layers, or generate it.
• A layer's box is two fields. transform.position is a point in composition pixels, top-left origin, and the layer's anchor lands on it. The anchor is the box's centre for every content kind except text, so measure each reference element to its centre, not its corner. Its size is content.bounds ([w, h]) on media and nested scenes, and content.size on a colour. Media without bounds fills the whole frame.
• Text never reflows. A scene has no wrap and no maximum width, so a long line runs straight out of the box around it. Break lines yourself with \n.
• A frame at exactly the scene's duration renders black. Take stills strictly inside it.
• The same media URL may fill two boxes as it is. Never make it unique per use.
• Keep what you measured: the fragment plan, the beat tables, the tracking results and the checks, so the user can see what you saw.