Track discovery and single-track extraction.
track_ids/1 and find_trak/2 locate tracks by their tkhd track_id;
extract_track/2 (added later) produces a new single-track tree.
Summary
Functions
Return a new box tree containing only the track track_id, with mdat rebuilt as a
segment list of that track's chunks and stco/co64 recomputed. Memory-safe: with a
lazy source the segments are FileSlices streamed on write/2.
Find the trak box whose tkhd track_id matches, or nil.
List every track's track_id, in document order.
Functions
Return a new box tree containing only the track track_id, with mdat rebuilt as a
segment list of that track's chunks and stco/co64 recomputed. Memory-safe: with a
lazy source the segments are FileSlices streamed on write/2.
Find the trak box whose tkhd track_id matches, or nil.
List every track's track_id, in document order.