histogram_codec + backfill: tighter peak ceiling, preserve bw_report

histogram_codec: drop _MAX_PEAK_COUNT 4096 → 2200. The old ceiling
let extension-byte blocks slip through at up to 20.48 in/s per
channel, producing 35× inflated PVS sums when first deployed to
prod. 2200 covers Normal-range full-scale (10 in/s = 2000 counts)
plus 10% headroom for quantization edge cases.

backfill_sidecars: also preserve the bw_report block alongside
review + extensions when regenerating sidecars. event_to_sidecar_dict
takes a BwAsciiReport dataclass not a dict, so for bw_report we
overlay the existing block after regen rather than passing as a kwarg.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
This commit is contained in:
2026-05-21 02:50:10 +00:00
parent bc5a2d3f19
commit e949232875
2 changed files with 31 additions and 13 deletions
+13 -6
View File
@@ -101,11 +101,13 @@ _BLOCK_SIZE = 32
# additional validation that we're looking at a real block.
_BLOCK_MARKER = 10
# Maximum plausible peak-count value. Normal-range geophone tops out
# at 10 in/s = 2000 counts at the 0.005 in/s per count scale; even
# Sensitive range (1.25 in/s FS) wouldn't exceed ~250. Mic counts run
# 0..~400 in observed data. 4096 leaves comfortable headroom for any
# legitimate value across all modes.
# Maximum plausible peak-count value. The geophone tops out at 10 in/s
# at Normal range = 2000 counts at the 0.005 in/s per count scale.
# Sensitive range (1.25 in/s FS) tops at ~250. Mic peak counts have
# been observed up to ~400 (≈ 100 dB(L)) and per the protocol doc can
# reach ~813 (140 dB(L)). 2200 covers Normal full-scale plus ~10%
# headroom for quantization edge cases while keeping every physically
# implausible value out of the PVS computation.
#
# Some prod blocks have been observed with peak-count fields whose
# HIGH byte is non-zero (block[7] != 0 etc.) — observed across BE9558
@@ -116,7 +118,12 @@ _BLOCK_MARKER = 10
# device writes in some sub-mode (possibly Histogram+Continuous).
# Until reverse-engineered, blocks exceeding this bound are skipped
# rather than propagating bogus values into PVS computations.
_MAX_PEAK_COUNT = 4096
#
# Earlier we tried 4096 — that allowed peak counts up to 4096 × 0.005
# = 20.48 in/s per channel, which produced 35× inflated PVS sums when
# the extension-byte blocks slipped through. See feat/wire-histogram-codec
# branch history for the rollback.
_MAX_PEAK_COUNT = 2200
# Geo peak scaling: stored as "count × 0.005 in/s" where 1 count = one
# 0.005 in/s display quantum. Equivalent to the waveform codec's