Synthesia Layouts (100+ designs) vs Sume compose: stack or overlay

Synthesia's Layouts are a library of 100+ ready-made scene designs in its Editor. Sume has no design library: compose takes one still and one video and returns one MP4 with both on screen, using operation set to stack or overlay. Anything beyond those two arrangements is yours to build.

Synthesia facts are from its updates page (entry dated 9/2/2026); Sume facts from Timeline compose, read 2026-10-01.

What did Synthesia ship?

The entry describes Layouts as a library of 100+ ready-made designs right in the Editor, with instant theme previews and one-click swaps in Storyboard. It is an editor feature, so there is no API claim to compare against.

What does Sume compose give me instead?

Compose takes one still plus one video and returns one MP4 with both on screen at once. Required fields are operation (stack or overlay), image.url and video.url. Optional layout and output fields exist for placement and size; the docs describe the full field list.

How do I build a full scene sequence?

Compose makes one shot. Sequencing, transitions and the audio spine stay on Timeline 1.0: render a compose, then drop its video_url into a video[] slot. For a presenter with graphics, see talking head video with graphics.

Which one should I use?

If you want to pick from a catalog of scene designs by eye, that is Synthesia's editor. If you want a repeatable API step that places one still against one video, use compose. Import both files first with POST /v1/media-imports; an Idempotency-Key is required.