Timeline invalid_segment_timing and segment_overlap: fix your starts
Sume timeline returns invalid_segment_timing or segment_overlap when video starts do not increase or slots overlap past the transition. Fix the start values.
invalid_segment_timing and segment_overlap from Sume Timeline 1.0 mean that your video[].start values do not increase, or two slots overlap by more than their crossfade. Fix the starts so each one is later than the one before, and keep video[0].start at exactly 0. Run the unbilled /plan call first to see the problem without a charge. Source: Timeline 1.0, read 2026-10-06.
What are the timing rules?
Declared starts are authoritative, and the compiler compensates for a crossfade without pre-shifting your numbers.
| Rule | Value | Code when broken |
|---|---|---|
| First slot start | video[0].start is 0 | timeline_must_start_at_zero |
| Later starts | Must increase | invalid_segment_timing |
| Overlap | Not past the xfade | segment_overlap |
| Transition on first slot | Not allowed | transition_on_first_segment |
| Slot length | At least 0.2 s | See the program table |
How do I fix it?
Compute each start as the previous start plus the previous on-screen duration. A transition is at most 1 second and at most 50% of the shorter neighbour, so keep slots long enough for the fade you ask for. Coverage may stop at most 0.5 seconds before the end of the spine.
- Use
POST /v1/timeline-1.0/planbefore the paid render; it is unbilled. - Slots go up to 200 per timeline; more than 12 chunk automatically on
render.strategy: auto. - Price is $0.10 per ceil output minute.
Sources
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