The segment-channel scoring analyzer (from scratch/next_experiment_skeleton.py)
ran and immediately confirmed the rotation hypothesis:
SP0 seg 0: best fit Vert 508/508 ✓
SP0 seg 1: best fit Long 508/508 ✓
SP0 seg 3: best fit Tran 508/508 ✓ (Tran continuation)
SP0 seg 5: best fit Long 508/508 ✓
SP0 seg 9: best fit Long 508/508 ✓
V70 seg 0: best fit Vert 508/508 ✓
V70 seg 1: best fit Long 508/508 ✓
Channels rotate Tran → Vert → Long → MicL per 40 02 segment header.
Also discovered the segment header has DOUBLE duty: bytes [14:18] anchor
the NEW segment's channel (2 samples as int16 BE in 16-count units), AND
bytes [0:4] extend the PREVIOUS channel by 2 more samples (2 deltas as
int16 BE). This is the same "2 anchors + delta stream" structure as the
body preamble for Tran.
decode_waveform_v2 now returns full per-channel sample dicts.
Byte-exact verified ranges:
V70: Tran 512, Vert 512, Long 512 (all first segments)
JQ0: Tran 512, Vert 258
SP0: Long 1536 (all 3 L segments)
Still open: the 30 NN block format (high-amplitude packed deltas) —
appears mid-segment when single-byte deltas can't carry the magnitude.
6 new tests bring the count to 46. All passing.
Claude