Verified against a second Thor corpus (9-10-26-csv-req: UM11402, UM12947,
UM20147) with per-sample CSV exports: 139/139 waveforms exact
(1,273,380/1,273,380 samples) and 877/877 histograms within 2% of Thor's
reported PPV -- up from 66.9% and 56.6%.
Some units run with the microphone disabled, which changes two structural
things that were both hardcoded to the 4-channel shape:
- Waveform body head sat below the scan floor. A 3-channel unit has a
shorter fixed header and puts its record chain head at 0x0dba, under the
old _BODY_SCAN_FLOOR of 0x0E00. The scan could not see it and fell
through to the Vert segment-0 record, decoding a body shifted one
position around the channel rotation -- Vert came up exactly 512 samples
short. Floor lowered to 0x0C00. The body-offset scoring also had to stop
requiring four channels, or `equal` is permanently False for these events
and the pick falls back to raw sample count.
- Histogram interval record is 56 bytes, not 72. It is
16 * n_channels + 8, and is not inferable from the segment length alone.
The interval count now comes from the segment's cumulative counter
(n = counter - prev_counter) and the stride is derived from it. Assuming
72 read 7 intervals out of every 10-interval segment, then walked off
alignment into garbage that decoded as ~10 in/s peaks -- inflating some
files' PPV by up to 191,000%. Also recovers 4 files that previously
decoded no intervals at all.
Combined across both corpora: 292/292 waveform files,
2,330,916/2,330,916 samples exact. Production IDFW truncations 41 -> 22.
Series-3 unaffected (no shared-codec change in this commit; last full run
14,338/14,338).
Known open, diagnosed but NOT verified: the remaining 22 unequal + 1 failing
production IDFW files (all UM12947, 2025-07-14..09-23) stop the block walker
on tag 40 0c. data_block_len() caps the 40 NN int16 block at NN > 0x08 while
those files use NN up to 196. Both verified corpora only ever use
NN in {1,2,3,4,8}, so the cap is untested there and lifting it leaves both at
100.000% -- which is not evidence it decodes these correctly. Deliberately
not shipped; needs Thor CSV exports for UM12947 in that date range.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Ru8Lg9HkkYvX9VWWo65SmL
serversdownandClaude Opus 5
c07aaa552c