File size: 2,719 Bytes
a84fca7 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 | #!/usr/bin/env python3
"""Motion fingerprint of a binary FBX: the per-curve value ranges.
Two exports of the same motion that differ only by a trailing hold share every
curve's (min, max) pair, while genuinely different motions do not. Comparing the
whole multiset is far stricter than comparing a single peak-to-peak figure,
which can coincide by chance.
"""
import os, struct, sys, zlib
SCALAR = {"Y": 2, "C": 1, "I": 4, "F": 4, "D": 8, "L": 8}
ELEM = {"f": 4, "d": 8, "l": 8, "i": 4, "b": 1}
FMT = {"f": "f", "d": "d", "l": "q", "i": "i", "b": "b"}
def probe(path, nd=3):
d = open(path, "rb").read()
if d[:21] != b"Kaydara FBX Binary \x00":
raise ValueError("not a binary FBX")
u64 = struct.unpack("<I", d[23:27])[0] >= 7500
NREC = 25 if u64 else 13
curves = []
def rd_prop(p, want):
t = chr(d[p]); s = p; p += 1
if t in SCALAR: p += SCALAR[t]; return p, None
if t in ELEM:
n, enc, clen = struct.unpack("<III", d[p:p+12]); p += 12
body = clen if enc else n * ELEM[t]
raw = d[p:p+body]; p += body
if want and n:
try:
if enc: raw = zlib.decompress(raw)
return p, struct.unpack("<%d%s" % (n, FMT[t]), raw[:n*ELEM[t]])
except Exception: return p, None
return p, None
if t in "SR":
ln = struct.unpack("<I", d[p:p+4])[0]; p += 4 + ln; return p, None
raise ValueError("bad prop %r" % t)
def rd_node(p):
if u64: end, nprop, plen = struct.unpack("<QQQ", d[p:p+24]); q = p+24
else: end, nprop, plen = struct.unpack("<III", d[p:p+12]); q = p+12
if end == 0 and nprop == 0 and plen == 0: return p + NREC
nl = d[q]; q += 1; name = d[q:q+nl]; q += nl
p = q; want = name == b"KeyValueFloat"; vals = None
for _ in range(nprop):
p, v = rd_prop(p, want)
if v is not None: vals = v
if want and vals:
curves.append((round(min(vals), nd), round(max(vals), nd), len(vals)))
while p < end:
if d[p:p+NREC] == b"\x00"*NREC: p += NREC; break
p = rd_node(p)
return end
p = 27
while p < len(d) - 160:
if d[p:p+NREC] == b"\x00"*NREC: break
p = rd_node(p)
ranges = tuple(sorted((a, b) for a, b, _ in curves)) # ignores key counts
return {"num_curves": len(curves), "ranges": ranges,
"keys": tuple(sorted(c for _, _, c in curves))}
if __name__ == "__main__":
for f in sys.argv[1:]:
r = probe(f)
print("%-30s curves=%-5d fingerprint=%s" % (
os.path.basename(f), r["num_curves"], hash(r["ranges"])))
|