GearScope hyperframes functional-verification log (asserting on actual output)
Date: 2026-08-17 | Host: macOS 26.5.2 aarch64 | Node v24.13.1 | FFmpeg 8.0.1

ASSERT 1 — rendered artifact is a real 1080p30 H.264 MP4 of the right length
$ ffprobe -v error -show_entries format=duration,size:stream=codec_name,width,height,r_frame_rate -of default=noprint_wrappers=1 renders/demo-video_2026-08-17_12-04-47.mp4
codec_name=h264
width=1920
height=1080
r_frame_rate=30/1
duration=4.000000
size=170120
✅ PASS — input HTML declared 1920x1080, 4s; output matches exactly

ASSERT 2 — determinism claim: same input renders byte-identical video
$ npx -y hyperframes@0.7.109 render        # second run, same input
EXIT: 0
$ md5 -q renders/demo-video_2026-08-17_12-04-47.mp4 renders/demo-video_2026-08-17_12-04-*.mp4
b66813f0cdc07aff2c9d77e6584bb747  170120   (run 1)
b66813f0cdc07aff2c9d77e6584bb747  170120   (run 2)
cmp -s → BYTE-IDENTICAL
✅ PASS — two independent renders produce the same md5; the README's
  "same input, same frames, same output" claim held in this environment

ASSERT 3 — negative case: broken timeline registration is caught with a fix
$ python3 - <<EOF  # point window.__timelines at a nonexistent composition id
  html.replace('window.__timelines["main"]', 'window.__timelines["other"]')
EOF
$ npx -y hyperframes@latest check > check.log 2>&1; echo $?
1
✗ timeline_id_mismatch: Timeline registered as "other" but no element has
  data-composition-id="other". The runtime cannot auto-nest this timeline.
  Fix: Change window.__timelines["other"] to match the data-composition-id
  attribute, or vice versa.
✅ PASS — exit 1, error names the rule, the file, the element, and the fix

OBSERVATION (not counted) — a clip whose data-start/duration extend past the
composition end (sub clip ends at 4s in a 2s composition) passes check with
0 issues; the engine appears to tolerate/clamp overhanging clips silently.

Functional verdict: 3 of 3 asserts pass. The core claims (deterministic local
HTML-to-MP4 rendering, lint that catches real authoring errors) are verified
end to end without any paid service.