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2taud.py: fix: stereo samples not converting correctly

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minjaesong
2026-05-21 02:55:41 +09:00
parent 8e8374ba99
commit 5b9b96c8de
3 changed files with 50 additions and 22 deletions
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29
it2taud.py
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@@ -294,11 +294,11 @@ def _it214_decompress_block(payload: bytes, num_samples: int,
return out
def it214_decompress(blob: bytes, smp_offset: int, num_samples: int,
is_16bit: bool, is_it215: bool) -> bytes:
"""Decode IT2.14/IT2.15 compressed sample data. Returns raw PCM bytes (signed)."""
def _it214_decompress_channel(blob: bytes, pos: int, num_samples: int,
is_16bit: bool, is_it215: bool) -> tuple:
"""Decode one channel of IT2.14/IT2.15 compressed data. Returns
(raw PCM bytes, next position after consumed blocks)."""
block_size = 0x4000 if is_16bit else 0x8000
pos = smp_offset
out_samples = []
while len(out_samples) < num_samples:
@@ -318,9 +318,24 @@ def it214_decompress(blob: bytes, smp_offset: int, num_samples: int,
result = bytearray(len(out_samples) * 2)
for i, s in enumerate(out_samples):
struct.pack_into('<h', result, i * 2, max(-32768, min(32767, s)))
return bytes(result)
return bytes(result), pos
else:
return bytes(s & 0xFF for s in out_samples)
return bytes(s & 0xFF for s in out_samples), pos
def it214_decompress(blob: bytes, smp_offset: int, num_samples: int,
is_16bit: bool, is_it215: bool,
is_stereo: bool = False) -> bytes:
"""Decode IT2.14/IT2.15 compressed sample data. Returns raw PCM bytes
(signed). For stereo samples, returns the left channel block followed
by the right channel block (matching IT's on-disk SF_SS layout)."""
left, pos = _it214_decompress_channel(blob, smp_offset, num_samples,
is_16bit, is_it215)
if not is_stereo:
return left
right, _ = _it214_decompress_channel(blob, pos, num_samples,
is_16bit, is_it215)
return left + right
# ── IT sample parser ──────────────────────────────────────────────────────────
@@ -384,7 +399,7 @@ def parse_samples(data: bytes, h: ITHeader, decompress: bool) -> list:
try:
is_it215 = bool(s.cvt & 0x04)
raw = it214_decompress(data, s.smp_point, s.length,
s.is_16bit, is_it215)
s.is_16bit, is_it215, s.is_stereo)
s.sample_data = normalise_sample(raw, True,
s.is_16bit, s.is_stereo, s.name)
s.length = len(s.sample_data)