preResolveClip abstract method
Probes source and extracts every source frame in sourceFrames,
decoding each to a ui.Image cached by (source, frame) so paint can
read it synchronously.
Runs in the pre-resolve pass before the frame loop and is idempotent: a
frame already extracted is skipped. Throws a FluvieRenderException when
the source cannot be probed or a frame cannot be extracted.
Implementation
Future<void> preResolveClip(MediaSource source, Iterable<int> sourceFrames);