Review, render and ship

Your film is going to the feeds. Here is the 16:9 master turned into a 9:16 phone cut two ways. Tick the overlay to see what the app's own buttons cover.

The crop cuts the line in half and loses the product. The re-layout is a new composition on the same timeline. That is the last step of a film. Before it comes the review.

Review against its own register

Numbers first, taste second. A film is judged against the medians of its own register: a product-camera film next to a motion-graphics one always looks too still.

The skill reviews a film on eleven rows. Each row has an owner and a target.

Write each finding as one row: what you saw, what to change, why.

A film is a function of time

When a film is built from code, as with HeyGen's HyperFrames, every frame must be a pure function of the time t. No Math.random(), no clock, nothing carried from the last frame. Seeded randomness is fine.

That rule buys real motion blur. The renderer samples several moments inside each frame and averages them: a 180° shutter, four samples a frame by default, up to 24 on a whip pan. One unseeded Math.random makes those samples disagree and the blur turns to noise.

Place everything on a beat grid taken from the actual track, not from the brief. A generated track's tempo is a hope until measured: over 50 s, a 0.15 % tempo error puts the last hits about 70 ms late, past the 30 ms sync budget.

Delivery gates

Hand nothing over until every file passes.

1. Frame count matches

   A mux with -shortest silently drops the last frames when the audio ends early.

2. H.264 level fits

   Level ≤ 4.2 at 1080p, ≤ 5.2 at 4K. A slow preset without -level writes 6.0, which fails in Safari, QuickTime and on phones.

3. Under 1 GB at 4K

   CRF around 12 at a slower preset; higher quality nobody can see just doubles the file.

4. Decodes on the hardware decoder

   That is what phones use; a software decode passing proves nothing.

5. Loudness written, −1 dBTP

   For the register, chosen on purpose. −14 LUFS is an engine default, not a standard.

The formats around the film

A launch film rarely ships alone. Each companion breaks a different rule of the master.

• Feature loop for the landing page: a cycle, not enter-hold-exit. The last frame flows into the first with no visible seam; frame 0 is the poster and names the product. Ship MP4/WebM; GIF only at 25 or 50 fps (GIF delays are whole hundredths, so 30 fps plays 11 % fast).
• Logo sting: 3-8 s, the name plus three words at most. Assemble the mark from 2-4 pieces with one hit on contact; hold the lockup at least 1.5 s.
• Vertical and square: re-lay out, never crop. In 9:16 keep text inside top 270, right 120, bottom 420 and left 64 px of a 1080 × 1920 frame, type about 1.4× its 16:9 size, captions burned in because feeds autoplay muted. Those are the safe zones.

Who owns what

Three build tools appear next to the skill. The split is the same each time: the tool owns the build; the skill owns register, beats, type cadence and sound.

Review this render against its own register, at its native frame rate.
Recount cuts by eye from a contact sheet around each seam; don't trust a
detector count. Go through the 11 rows (register, hook, name, words, UI
demo, motion, seams and cuts, endcard, sound sync, level, source) and
write one Before | After | Why row per issue. Then check the delivery
gates: frame count, H.264 level, size, hardware decode, loudness and
-1 dBTP. Make the 9:16 cut as a re-layout inside the feed safe zones.