Claude
d3f77d1d96
Decoded the structural framing of the Blastware waveform body — the bytes between the 21-byte STRT record and the 26-byte file footer. The body is a sequence of tagged variable-length blocks, NOT raw int16 LE. Five tag types (10/20/00/30/40 NN) and their lengths are now confirmed against the 4-event May 2026 fixture bundle. Body splits cleanly into ~16 segments (for a 1280-sample event) separated by 40 02 segment headers carrying a monotonically incrementing uint32 LE counter at bytes [8:12]. What's done: - minimateplus/waveform_codec.py — block walker, segment splitter, segment header parser. decode_waveform_v2 is a stub returning None until the byte-to-sample mapping is solved; client.py is unchanged. - tests/test_waveform_codec.py — 31 tests covering block detection, lengths, contiguous-walk, segment splitting, segment-header parsing, and counter monotonicity. All pass. - tests/fixtures/decode-re-5-8-26/ — bundled fixtures (4 events, BW binary + Blastware ASCII export each). - docs/instantel_protocol_reference.md §7.6.1 — replaced retraction box with the verified structural decoding plus an explicit list of what's still open. What's still open: the per-byte mapping inside 10 NN / 20 NN blocks. 96 channel-permutation × nibble-order × sign-convention combinations were brute-force tested; none match BW's ASCII export to within ±1 ADC count. The codec is more elaborate than uniform 4-bit deltas — likely a hybrid variable-bit-width scheme with segment-anchor resync points. Next recommended step: capture an event with a known calibration tone to pin down magnitude scaling. Walker also bails out partway through event-b (open issue documented in both the module and the protocol reference).
69 lines
2.3 KiB
Python
69 lines
2.3 KiB
Python
"""
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Walker v6: handle 40 02 blocks correctly (length 20).
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Block formats:
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- [10 NN]: 4-bit nibble delta data, length = NN/2 + 2
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- [20 NN]: int8 literal data, length = NN + 2
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- [00 NN]: 2-byte marker
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- [30 NN]: trailer/summary block, length = NN*4
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- [40 02]: segment header, fixed length 20
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"""
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import sys
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sys.path.insert(0, ".")
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from analysis.load_bundle import load_bundle
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from collections import Counter
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def walk(body, start, max_blocks=10000):
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i = start
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blocks = []
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while i + 1 < len(body) and len(blocks) < max_blocks:
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t0 = body[i]
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t1 = body[i + 1]
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if t0 == 0x10 and t1 % 4 == 0 and 0 < t1 <= 0xFC:
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length = t1 // 2 + 2
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elif t0 == 0x20 and t1 % 4 == 0 and 0 < t1 <= 0xFC:
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length = t1 + 2
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elif t0 == 0x00 and t1 % 4 == 0:
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length = 2
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elif t0 == 0x30 and t1 % 4 == 0 and 0 < t1 <= 0x10:
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length = t1 * 4
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elif t0 == 0x40 and t1 == 0x02:
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length = 20
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else:
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blocks.append((i, "??", t0, bytes(body[i:i+8]), 0))
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break
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if i + length > len(body):
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break
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data = bytes(body[i + 2 : i + length])
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blocks.append((i, f"{t0:02x}", t1, data, length))
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i += length
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return blocks, i
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def main():
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for name in ("event-c", "event-d", "event-a", "event-b"):
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b = load_bundle(name)
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body = b.body
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for s in range(15):
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if body[s] == 0x10 and body[s+1] % 4 == 0 and 0 < body[s+1] <= 0xFC:
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start = s; break
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else:
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start = 7
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blocks, end = walk(body, start)
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types = Counter(bb[1] for bb in blocks)
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print(f"\n=== {name} === body={len(body)} N={len(b.samples['Tran'])} start={start}")
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print(f" total blocks: {len(blocks)}, walk ended at {end}/{len(body)}")
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print(f" type counts: {dict(types)}")
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if blocks and blocks[-1][1] == "??":
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print(f" stopped at byte: 0x{blocks[-1][2]:02x} at offset {blocks[-1][0]}")
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print(f" prev 5 blocks: {[(bb[0], bb[1], bb[2]) for bb in blocks[-6:-1]]}")
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print(f" bytes around stop: {body[end-4:end+24].hex(' ')}")
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# Sum
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payload_sizes = {t: sum(len(bb[3]) for bb in blocks if bb[1] == t) for t in types}
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print(f" payload bytes by type: {payload_sizes}")
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if __name__ == "__main__":
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main()
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