Sequencing translation: Sequence, Series, Composition root

How Remotion's nested Sequence tree maps to one sub-composition host per scene in the root, each with its own paused GSAP timeline in local time.

The core idea

Remotion's <Sequence from={F} durationInFrames={D}> is a coordinate transform: it shifts useCurrentFrame() by F and clips the child component to the window [F, F+D]. HF doesn't have a per-element "current frame" — there's a single composition seek time and the runtime hides/shows elements based on their data-start / data-duration.

Result: the nested tree flattens into a list of scene hosts on the same parent, each with its own time window; each scene's content lives in its own sub-composition file.

<Composition> → root #stage

<Composition
  id="MyVideo"
  component={MyVideo}
  durationInFrames={300}
  fps={30}
  width={1280}
  height={720}
/>

<div
  id="stage"
  data-composition-id="MyVideo"
  data-start="0"
  data-duration="10"      <!-- 300/30 -->
  data-fps="30"
  data-width="1280"
  data-height="720"
>
  <!-- composition content -->
</div>

data-start="0" is required on #stage (the runtime needs it to anchor playback; missing it triggers a lint warning).

<AbsoluteFill> → positioned div

<AbsoluteFill style={{ backgroundColor: "#0a0a0a" }}>...children...</AbsoluteFill>

<div style="position:absolute;inset:0;background-color:#0a0a0a;">...children...</div>

AbsoluteFill is just a styled div in Remotion. Translate to a div with position:absolute; inset:0 and copy through any other style props.

<Sequence> → sub-composition host

<Sequence from={0} durationInFrames={90}>
  <TitleCard />
</Sequence>

The root #stage only holds a host per scene; the scene's markup, styles and timeline live in their own sub-composition file, so the Studio timeline gets one readable row per scene and the lint has no nested structure to flag.

<!-- index.html -->
<div
  id="scene-1"
  class="clip"
  data-composition-id="scene-1"
  data-composition-src="compositions/scene-1.html"
  data-start="0"
  data-duration="3"
  data-track-index="0"
></div>

<!-- compositions/scene-1.html: TitleCard children inlined, timeline keyed "scene-1", local time starts at 0 -->
<template id="scene-1-template">
  <div data-composition-id="scene-1" data-width="1280" data-height="720" data-duration="3">
    <!-- TitleCard children -->
    <script>
      const tl = gsap.timeline({ paused: true });
      window.__timelines["scene-1"] = tl;
    </script>
  </div>
</template>

Convert frames to seconds: from/fps, durationInFrames/fps. Pick a data-track-index per parallel rendering layer (background = 0, overlays = 1, audio = 2, etc.). Sequential scenes can share an index. Inside the sub-composition, time is local: a tween that started at F/fps in the root starts at 0 here. Asset paths are relative to the sub-composition file (../assets/x.png).

Nested <Sequence> flattens

Remotion adds offsets when sequences nest:

<Sequence from={60} durationInFrames={120}>
  <Sequence from={30} durationInFrames={60}>
    <ImageScene />
  </Sequence>
</Sequence>

The inner sequence's effective window is [60+30, 60+30+60] = [90, 150].

Translate by computing the sum and emitting one host with the resolved window; the scene's children go in its sub-composition file:

<div
  data-composition-id="image-scene"
  data-composition-src="compositions/image-scene.html"
  data-start="3"
  data-duration="2"
  data-track-index="0"
></div>

<Series> → siblings with sequential offsets

<Series>
  <Series.Sequence durationInFrames={60}>
    <A />
  </Series.Sequence>
  <Series.Sequence durationInFrames={120}>
    <B />
  </Series.Sequence>
  <Series.Sequence durationInFrames={90}>
    <C />
  </Series.Sequence>
</Series>

Each Sequence.Sequence lives in the next time slot. Emit siblings with data-start accumulating (each host mounts its scene file):

<div
  data-composition-id="a"
  data-composition-src="compositions/a.html"
  data-start="0"
  data-duration="2"
  data-track-index="0"
></div>
<div
  data-composition-id="b"
  data-composition-src="compositions/b.html"
  data-start="2"
  data-duration="4"
  data-track-index="0"
></div>
<div
  data-composition-id="c"
  data-composition-src="compositions/c.html"
  data-start="6"
  data-duration="3"
  data-track-index="0"
></div>

Crossfading scene boundaries

Remotion <Sequence> shows/hides at hard boundaries by default. HF does the same — but if your composition needs a smooth fade between scenes, you have to drive opacity explicitly with GSAP at the boundary. A scene can hard-cut itself with gsap.set at its local end (the corpus fixtures do). A fade between two scenes goes on the scene hosts from the root timeline, since a scene's own timeline only sees its own file:

const tl = gsap.timeline({ paused: true });
tl.set(scene1, { opacity: 1 }, 0);
tl.set(scene1, { opacity: 0 }, 2); // hard cut at 2s
tl.set(scene2, { opacity: 1 }, 2);

For a 0.5 s crossfade:

tl.to(scene1, { opacity: 0, duration: 0.5 }, 1.5);
tl.to(scene2, { opacity: 1, duration: 0.5 }, 1.5);

For Remotion <TransitionSeries> translations see transitions.md.

<Loop>

<Loop durationInFrames={30}>
  <Spinner />
</Loop>

HF doesn't have a <Loop> primitive. Translate it to a bounded GSAP timeline using the time available at its insertion point:

const cycleDuration = 1;
const availableDuration = compositionDuration - 3;
const repeat = Math.max(0, Math.floor(availableDuration / cycleDuration) - 1);
const spinTl = gsap.timeline({ paused: true, repeat, repeatRefresh: false });
spinTl.to(spinner, { rotate: 360, duration: 1.0, ease: "none" });
// Embed in the main composition timeline at the right offset:
mainTl.add(spinTl, 3);

This is fragile — Remotion's <Loop> resets internal state every iteration, which GSAP repeat does too, but if the looped child has its own animation, you need to be careful that GSAP's repeatRefresh is on or off as needed. The finite count is required because HyperFrames seeks a bounded composition frame-by-frame.

<Freeze>

<Freeze frame={30}>
  <Animated />
</Freeze>

Drop the wrapper. <Freeze> pins useCurrentFrame() at a constant for the children — but in HF, the children's animation is already driven by explicit GSAP tweens, so freeze translates to "don't tween this element".

Multiple parallel tracks

When you have a background video + overlay text + audio playing simultaneously, use distinct data-track-index values:

<div data-track-index="0">background video</div>
<div data-track-index="1">overlay text</div>
<audio data-track-index="2" ...></audio>

The runtime picks track ordering from the index. See media.md for media-specific track conventions.