63 lines
1.9 KiB
Python
63 lines
1.9 KiB
Python
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#!/usr/bin/env python3
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"""对比 A/B 两版的双耳空间分离度。
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指标: 左右声道去均值后的相关系数。
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接近 1.0 = 两耳听到的几乎一样 -> 声音"钉在头中间"(普通耳机听 5.1 的听感)
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明显偏低 = 两耳有差异 -> 携带了方位信息(HRTF 起了作用)
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"""
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import os
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import struct
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import wave
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def read_stereo(path: str) -> tuple[list[float], list[float]]:
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"""读 wav 的前两个声道。"""
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with wave.open(path) as w:
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channels = w.getnchannels()
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raw = w.readframes(w.getnframes())
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frames = struct.unpack("<%dh" % (len(raw) // 2), raw)
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left: list[float] = []
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right: list[float] = []
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for i in range(0, len(frames) - channels + 1, channels):
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left.append(float(frames[i]))
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right.append(float(frames[i + 1]) if channels > 1 else float(frames[i]))
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return left, right
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def centered(xs: list[float]) -> list[float]:
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"""去均值。"""
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if not xs:
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return []
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mean = sum(xs) / len(xs)
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return [x - mean for x in xs]
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def correlation(a: list[float], b: list[float]) -> float:
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"""皮尔逊相关系数。"""
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num = sum(x * y for x, y in zip(a, b))
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da = sum(x * x for x in a) ** 0.5
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db = sum(y * y for y in b) ** 0.5
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return num / (da * db) if da and db else 0.0
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def rms(xs: list[float]) -> float:
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"""均方根。"""
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return (sum(x * x for x in xs) / len(xs)) ** 0.5 if xs else 0.0
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def main() -> int:
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os.chdir(os.path.dirname(os.path.abspath(__file__)))
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print("%-22s %10s %10s %10s" % ("文件", "相关性", "L 均方根", "R 均方根"))
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print("-" * 58)
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for name in ("A-普通下混.wav", "B-HRTF环绕.wav"):
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if not os.path.isfile(name):
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continue
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left, right = read_stereo(name)
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print("%-22s %10.3f %10.1f %10.1f"
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% (name, correlation(centered(left), centered(right)), rms(left), rms(right)))
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return 0
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if __name__ == "__main__":
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raise SystemExit(main())
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