How to Make Stacked Caption Blocks in After Effects (With AI Stacking)
Stacked blocks are the caption look you see on a lot of social videos: a few words at a time, stacked on top of each other, with one word much bigger than the rest. Captyne 1.5.8 and later build this look for you, and AI Stacking can decide where every block breaks and which word goes big.
Step 1: Turn on Stacked blocks
- Transcribe your clip, or load a transcript (see How to import SRT or VTT captions).
- Open the Preview tab. Next to the Interactive Preview, open the Stacked Blocks card.
- Switch on Stacked blocks.
While stacking is on, blocks break at sentence ends, commas and pauses. Words / Phrase and Words / Line from Grouping & Layout are not used.
Step 2: Set the block size and spacing
| Setting | What it does |
|---|---|
| Words / Block min and max | How many words each block may hold |
| Line padding (px) | Space between the lines of a block |
| Jitter | Off, Alternating or Random sideways offset for each line, for a hand-placed look |
| Jitter (px) | How far lines move sideways |
| Block position | Where blocks sit in the frame |
| Put two short words side by side | Keeps very short words on one line instead of giving each its own |
Tip: the Cumulative Words reveal mode suits stacked blocks best: each word appears as it is spoken and the block builds up.
Step 3 (optional): Let AI Stacking choose
Click ✨ AI Stacking. The AI reads the whole transcript once and decides:
- where each block starts and ends,
- how each block splits into lines,
- which word goes big.
It follows your Words / Block settings and your preset's Emphasis and Style 3 tags. The result opens in the Interactive Preview, where you can still move words between lines and blocks or change any word's style. Click AI Stacking again for a different version. Running it again on the same transcript and settings reuses the last result, so no tokens are spent.
AI Stacking is included with Individual Pro, Studio and Enterprise. On long videos it works in parts; if the AI skips a part, only that part uses the normal stacking rules and the AI's blocks are kept everywhere else (Captyne 1.5.9 and later).
Step 4: Generate, then fine-tune live
Click Generate. Then select the ACP_MASTER null in your comp and use its Stack controls: Line Padding, Jitter, Jitter Mode, Jitter Seed, Position and Edge Margin. Every block updates live in After Effects.
Changing padding, jitter or position in the Captyne panel also updates the open comp, so you can work from whichever side you prefer.
Troubleshooting
- "AI Stacking is a Pro feature": your plan is Starter. See plans.
- AI Stacking returned very few blocks on a long video: update to Captyne 1.5.9 or later. See How to update Captyne.
- Lines overlap after you change the font: use Edit Generated Captions so the words re-space.