The lock clamped currentTime only during the seeking event. HLS defers the
forward seek until the fragment loads, so that clamp caught it; but for
progressive MP4 the forward seek takes effect immediately and the mid-seek
write is ignored, so playback leaked past the watched point (snackbar showed,
no snap-back).
Keep the immediate seeking-time clamp (HLS relies on it to avoid buffering
ahead) and add an authoritative re-clamp in seeked: if the playhead still
landed past the limit, snap back via a backward seek into buffered content,
which holds. Snackbar now fires once per blocked gesture and only when a
clamp actually happens.
Rotimi Best
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