seam-craft

Name: seam-craft
Author: heygen-com

9.0kinstalls3.5kforks

How to install seam-craft?

heygen-com/hyperframes/seam-craft

$npx -y skills add heygen-com/hyperframes --skill seam-craft

Installs into the current project.

Summary

Render-correctness doctrine for scene-to-scene seams in HyperFrames launch videos — the prerequisites that make transitions composite correctly on the master timeline. Load when assembling the master timeline / index.html, when a white flash appears at a cut or crossfade seam (es

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SKILL.md

1	# Seam Craft — render prerequisites for scene-to-scene transitions
2
3	This is the render-correctness doctrine for PLV scene-to-scene seams: the
4	prerequisites and master-timeline mechanics that make any transition composite
5	correctly, independent of which specific transition is chosen. The per-transition
6	catalog (crossfade, push-slide, zoom-through, cut-the-curve, …) lives in the
7	transition registry — this page is the doctrine that sits underneath all of them.
8
9	The transitions this doctrine governs are Tier-B-ready: pure transform / opacity /
10	filter on the two scene clip wrappers (`#el-<sid>`), no injected overlay DOM, no
11	per-scene cooperation. Overlay families (staggered blocks, blinds, light leak, grid
12	dissolve, page burn) and shader transitions are deferred to later phases.
13
14	## Stage ground prerequisite (white-flash guard)
15
16	Several templates open a window where the two wrappers' summed opacity < 1 (the
17	cut-the-curve mid-window cut, zoom-through's 0.15 floor, plain crossfade's
18	power-curve dip). Whatever is BEHIND the wrappers shows through during that
19	window. If the assembled `index.html` `#root` has no opaque background, the
20	renderer composites the dip over its default white page → a white flash at
21	every seam, glaring on dark films (observed on two Spotify runs before the fix).
22	The assembler must paint the stage: `#root { background:
23	var(--canvas-deep, var(--canvas, #000)) }` — `assemble-index.mjs` now emits this;
24	any other consumer of these templates owns the same guarantee.
25
26	## How the injector applies a transition
27
28	At a `break` boundary between scene _i_ (`from`) and scene _i+1_ (`to`), the
29	injector:
30
31	1. Extends `#el-<from>` wrapper `data-duration` by `duration_s` (holds its final
32	frame — verified: `core/src/runtime/init.ts:1393-1410` external-slot branch).
33	2. Pulls `#el-<to>` wrapper `data-start` earlier by `duration_s` (creates the
34	overlap window).
35	3. Reassigns all clip `data-track-index` as a 0/1 ping-pong so the two
36	overlapping wrappers never share a track (same-track overlap is illegal —
37	`core/src/lint/rules/composition.ts`). Higher track composites on top.
38	4. Stamps the `gsap_template` into `window.__timelines["main"]` at `T = overlap-start`.
39
40	Verified by prototype render (2026-05-31): the master-timeline wrapper tween is
41	seeked and rendered (no double-seek with the sub-comp's own paused timeline —
42	the runtime drives them independently), the extended wrapper holds scene _i_'s
43	final frame, and the higher-track incoming wrapper composites over + blends with
44	the outgoing one.
45
46	## Template placeholders
47
48	The injector substitutes these tokens in each `gsap_template` line:
49
50	\| Token \| Meaning \|
51	\| ---------------------------------- \| ------------------------------------------------------------------------ \|
52	\| `__OLD__` \| `"#el-<from>"` — outgoing clip wrapper selector (quoted) \|
53	\| `__NEW__` \| `"#el-<to>"` — incoming clip wrapper selector (quoted) \|
54	\| `__T__` \| overlap-start time in seconds (master clock) \|
55	\| `__DUR__` \| `duration_s` for this boundary \|
56	\| `__DX__` \| horizontal travel for directional types: `-1920` (LEFT) / `1920` (RIGHT) \|
57	\| `__DY__` \| vertical travel: `-1080` (UP) / `1080` (DOWN) \|
58	\| `__ORIGIN_OUT__` / `__ORIGIN_IN__` \| transformOrigin pair for `squeeze` \|
59
60	`filter` / `scaleX` / `transformOrigin` are lint-clean on the master timeline
61	(verified: `core/src/lint/rules/gsap.ts` has no per-property whitelist and scopes
62	its checks to `data-composition-id` ranges; the x/y/scale/rotation/opacity
63	whitelist is a _scene-worker_ prompt rule only — it does not bind index.html).

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Type

seam-craft

9.0kinstalls3.5kforks

View on GitHub

How to install seam-craft?

heygen-com/hyperframes/seam-craft

$npx -y skills add heygen-com/hyperframes --skill seam-craft

Installs into the current project.

Summary

Files · 1

View on GitHub

SKILL.md

1	# Seam Craft — render prerequisites for scene-to-scene transitions
2
3	This is the render-correctness doctrine for PLV scene-to-scene seams: the
4	prerequisites and master-timeline mechanics that make any transition composite
5	correctly, independent of which specific transition is chosen. The per-transition
6	catalog (crossfade, push-slide, zoom-through, cut-the-curve, …) lives in the
7	transition registry — this page is the doctrine that sits underneath all of them.
8
9	The transitions this doctrine governs are Tier-B-ready: pure transform / opacity /
10	filter on the two scene clip wrappers (`#el-<sid>`), no injected overlay DOM, no
11	per-scene cooperation. Overlay families (staggered blocks, blinds, light leak, grid
12	dissolve, page burn) and shader transitions are deferred to later phases.
13
14	## Stage ground prerequisite (white-flash guard)
15
16	Several templates open a window where the two wrappers' summed opacity < 1 (the
17	cut-the-curve mid-window cut, zoom-through's 0.15 floor, plain crossfade's
18	power-curve dip). Whatever is BEHIND the wrappers shows through during that
19	window. If the assembled `index.html` `#root` has no opaque background, the
20	renderer composites the dip over its default white page → a white flash at
21	every seam, glaring on dark films (observed on two Spotify runs before the fix).
22	The assembler must paint the stage: `#root { background:
23	var(--canvas-deep, var(--canvas, #000)) }` — `assemble-index.mjs` now emits this;
24	any other consumer of these templates owns the same guarantee.
25
26	## How the injector applies a transition
27
28	At a `break` boundary between scene _i_ (`from`) and scene _i+1_ (`to`), the
29	injector:
30
31	1. Extends `#el-<from>` wrapper `data-duration` by `duration_s` (holds its final
32	frame — verified: `core/src/runtime/init.ts:1393-1410` external-slot branch).
33	2. Pulls `#el-<to>` wrapper `data-start` earlier by `duration_s` (creates the
34	overlap window).
35	3. Reassigns all clip `data-track-index` as a 0/1 ping-pong so the two
36	overlapping wrappers never share a track (same-track overlap is illegal —
37	`core/src/lint/rules/composition.ts`). Higher track composites on top.
38	4. Stamps the `gsap_template` into `window.__timelines["main"]` at `T = overlap-start`.
39
40	Verified by prototype render (2026-05-31): the master-timeline wrapper tween is
41	seeked and rendered (no double-seek with the sub-comp's own paused timeline —
42	the runtime drives them independently), the extended wrapper holds scene _i_'s
43	final frame, and the higher-track incoming wrapper composites over + blends with
44	the outgoing one.
45
46	## Template placeholders
47
48	The injector substitutes these tokens in each `gsap_template` line:
49
50	\| Token \| Meaning \|
51	\| ---------------------------------- \| ------------------------------------------------------------------------ \|
52	\| `__OLD__` \| `"#el-<from>"` — outgoing clip wrapper selector (quoted) \|
53	\| `__NEW__` \| `"#el-<to>"` — incoming clip wrapper selector (quoted) \|
54	\| `__T__` \| overlap-start time in seconds (master clock) \|
55	\| `__DUR__` \| `duration_s` for this boundary \|
56	\| `__DX__` \| horizontal travel for directional types: `-1920` (LEFT) / `1920` (RIGHT) \|
57	\| `__DY__` \| vertical travel: `-1080` (UP) / `1080` (DOWN) \|
58	\| `__ORIGIN_OUT__` / `__ORIGIN_IN__` \| transformOrigin pair for `squeeze` \|
59
60	`filter` / `scaleX` / `transformOrigin` are lint-clean on the master timeline
61	(verified: `core/src/lint/rules/gsap.ts` has no per-property whitelist and scopes
62	its checks to `data-composition-id` ranges; the x/y/scale/rotation/opacity
63	whitelist is a _scene-worker_ prompt rule only — it does not bind index.html).

People who liked this also viewed

6 picks

Type