The symptoms you see in the field are consistent: the editor plays fine in short demos but users report OOM kills during heavy scrubbing, preview stalls when multiple filters are applied, exports that crash mid‑way, and background uploads that never finish. Those failures come from a single design anti-pattern — eagerly materializing full‑resolution frames for many layers and operations instead of evaluating the timeline as a stream and bounding the working set. Contents [Why a non-destructive timeline beats in-place edits on mobile] [Designing a memory-safe pixel pipeline for constrained devices] [Delivering smooth, low-memory scrubbing and real-time preview] [Building a pragmatic, low-memory transcoding pipeline for export] [Crash-proofing: profiling, fail-safes, and UX signals] [Implementation checklist: ship a memory-safe timeline editor] Why a non-destructive timeline beats in-place edits on mobile A non-destructive timeline stores edits as metadata — ranges, trims, transforms, effect descriptors,…