File size: 3,329 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 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 | #!/usr/bin/env python3
"""Decide whether a binary FBX actually contains motion.
Keyframe *count* says nothing: a clip can carry 91 keys that all hold the same
value. This decodes the `KeyValueFloat` arrays of every animation curve (FBX
stores them zlib-compressed) and reports the largest peak-to-peak range found.
A file whose every curve is flat is static.
"""
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, eps=1e-6):
d = open(path, "rb").read()
if d[:21] != b"Kaydara FBX Binary \x00":
raise ValueError("not a binary FBX")
version = struct.unpack("<I", d[23:27])[0]
u64 = version >= 7500
NREC = 25 if u64 else 13
curves = [] # (name, peak-to-peak range, n)
def rd_prop(p, want_values):
t = chr(d[p]); s = p; p += 1
if t in SCALAR:
p += SCALAR[t]; return p, (t, d[s + 1:p])
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
vals = None
if want_values and n:
try:
if enc: raw = zlib.decompress(raw)
vals = struct.unpack("<%d%s" % (n, FMT[t]), raw[:n * ELEM[t]])
except Exception:
vals = None
return p, (t, vals, n)
if t in "SR":
ln = struct.unpack("<I", d[p:p + 4])[0]; p += 4
v = d[p:p + ln]; p += ln
return p, (t, v)
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"
props = []
for _ in range(nprop):
p, pr = rd_prop(p, want); props.append(pr)
if want and props and len(props[0]) == 3 and props[0][1]:
v = props[0][1]
curves.append((max(v) - min(v), len(v)))
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 = [r for r, _ in curves]
return {
"num_curves": len(curves),
"max_range": max(ranges) if ranges else 0.0,
"moving_curves": sum(1 for r in ranges if r > eps),
"static": bool(ranges) and max(ranges) <= eps,
"no_curves": not ranges,
}
if __name__ == "__main__":
for f in sys.argv[1:]:
try:
r = probe(f)
print("%-40s curves=%-5d moving=%-5d max_range=%-12.6g %s" % (
os.path.basename(f), r["num_curves"], r["moving_curves"],
r["max_range"], "STATIC" if r["static"] else ("NO_CURVES" if r["no_curves"] else "")))
except Exception as e:
print("%-40s ERROR %s" % (os.path.basename(f), str(e)[:50]))
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