Smoothing does not literally delay anything - a centred moving average has zero
phase lag - but it blurs onsets, so the visually salient moment of a mouth
opening moves later even though the mean does not. Animators also draw mouth
shapes a frame or two ahead of the sound as standard practice, so this is the
normal control rather than a workaround.
Only the performance tracks shift; the head and audio stay put, since it is the
mouth that should anticipate. In photo-underlay modes the vector mouth will
therefore no longer match the frame behind it, which is expected.
The lead is baked into the exported take - key f carries the pose from source
frame f+lead - so the Animator Pro renderer never needs to know about it.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Lip sync cannot be judged silently. extract.sh now pulls the audio track and
writes manifest.json alongside the frames; the page reads the true extraction
rate from it rather than assuming one, since a guessed fps desynchronises
picture from sound - the one thing this view exists to show.
Audio is the clock: frame = floor(currentTime * fps). A slow render loop drops
frames instead of drifting, and half/quarter speed work via playbackRate with
the picture following for free. Scrubbing, stepping and clicking a thumbnail
all seek the audio too.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
