Closes the last open question on the voice regions: why one cue s byte span
decodes to ~2.6x the movie s length.
The port measured, with controls including a cross-movie negative, that a
region s leading chunk is the TAIL of the full-length chunk that follows it --
r = 0.998 at a lag that puts it flush against that chunk s end, residual 16.7 dB
down over 84.5 s. They withdrew their own earlier 0.768, which came from a
search that scored best on the boundary of its own lag range.
Checked it here by an independent route that needs no decoder. If the leading
chunk is the tail of a full-length first stream, the whole leading stream should
be one complete take of chunk 1 s duration. For ADV: 504464 + 808304 = 1312768 B
at chunk 0 s byte rate of 9559.7 B/s is 137.323 s, against chunk 1 s measured
137.324 s. One millisecond over 137 seconds, from byte rates rather than from
envelope correlation.
And the byte structure settles the shape disc-wide. Counting stream starts inside
every inter-descriptor span: 258 hold exactly 1 stream, 28 hold exactly 3, and
nothing holds 2 or any other number. All 20 spans over 1.5 MB are 3-stream. The
95 movie regions decompose 70 + 8 + 17, and the 8 are independently the same 8
the first census found as bank-header-with-3-chunks.
So 359 s = 84.55 + 137.32 + 137.32: three presentations of one take, the first
clipped by resolve_movie_voice_region s own 1.5 MB guard.
Consequences recorded for the port: dropping the leading chunk is removing a
duplicate rather than truncating, so the hedge is lifted; but summing chunk 1
and chunk 2 is wrong, because they are the same take at different gain, not two
stems. Take one stream.
Also flags a coincidence I nearly built on: the 504464 B constant is structural,
not proportional -- ADV s proportional prediction lands within 8 bytes of it and
S00A s is 4305 B out.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
My own leading hypothesis -- that the leading chunk is an in-mission VOICE_D_*
line -- is refuted, on the route the port suggested: widen the enumeration past
the 95 manifest-bound movies and the byte-span test settles it without anyone
listening.
Scanning the stream for every trailer descriptor (the (id, 0x11) pair whose id
repeats at +0x800) gives the complete cue partition, mission lines included:
287 descriptors in a 116.2 MB window, all 287 carrying an id the 4280-name
registry names. Every one of the 17 leading spans is bracketed by
desc(N-1)..desc(N) where desc(N) is that movie s OWN cue id. Zero mission lines.
The mechanism is a guard in our own resolver. resolve_movie_voice_region takes
the predecessor trailer as the region start, guards it with
end - start < 1_500_000, and falls back to the .slb TOC anchor when that fails.
Cues with a true span over the guard: 17, of which 17 are stream-opening. Cues
under it: 78, of which 0. Perfect discrimination both ways. The anchor sits a
constant 504464 B after the true predecessor trailer on all 17, which is
unexplained.
Not established, and stated as such: this does NOT mean the export truncates N
seconds. The port s decode already has ADV s region at 359 s against a 137 s
movie, so it over-covers and the byte-to-time mapping is not linear. No XMA1
decoder in this container to check.
Also withdraws a claim this page had adopted from the port -- that chunks 1 and
2 are two stems of one performance. The port refuted its own claim by decoding:
S00A chunk 2 is digital silence, ADV chunk 2 is 0.60x chunk 1 with the residual
26.8 dB down. Equal duration was a shape match and Q10 s music census should not
have been carried across to voice on it.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01QsEPXWVaEpyfudtR6re1Pd
