hyperframes-repros

Minimal public reproductions for HyperFrames issues.

patch/host-duration-bound

A nested composition slot authored with data-duration (no data-end) does not bound the audio nested inside it in render. Visibility does close with the slot; the mixed audio does not.

• index.html: root 4s. Slot scene-a is data-start="0" data-duration="2" over a scene whose content is 4s. Slot scene-b follows at 2–4s.
• compositions/scene-a.html: <audio data-start="0" data-duration="4"> (silent until 1.5s, then a 440 Hz tone), plus a data-start="2.5" element that must never paint.
• compositions/scene-b.html: a plain blue scene that should be silent.

Expected: scene B is silent (the slot ended at 2s), the way the runtime already hides scene A's timed elements at 2s.

Actual (0.8.40): the compiled media plan lists scene-a-sound as start 0, end 4, and the tone plays over scene B (about −21 dB mean volume in 2–4s). The frame at 3s is correctly scene B: pixels and audio disagree about where the slot ends.

Reproduce

git checkout patch/host-duration-bound
npx [email protected] check          # clean
npm run render -- --debug -o out/repro.mp4 --quality draft
ffmpeg -ss 2 -t 2 -i out/repro.mp4 -vn -af volumedetect -f null - 2>&1 | grep mean_volume   # ≈ -21 dB, expected silence (-91 dB)

With --debug, compiled/summary.json in the producer .debug directory shows the planned window end: 4 for scene-a-sound.