fix: normalize ambience loudness for v0.2.5

tests/python/test_loudness_audio.py

@@ -0,0 +1,76 @@
+"""생성기와 독립된 새 ebur128 프로세스가 정확한 최종 WAV의 릴리스 계기다."""
+import hashlib
+import json
+import math
+from pathlib import Path
+import re
+import subprocess
+import unittest
+
+# manifest가 목표를 바꾸어 실패를 숨길 수 없도록 수용값을 독립적으로 고정한다.
+TARGET = -32.5
+CEILING = -6.0
+ROOT = Path(__file__).resolve().parents[2]
+
+
+def independent_measure(path):
+    """정규화 필터의 자기 보고 없이 저장된 전체 PCM을 전용 EBU 계기로 측정한다."""
+    command = ["ffmpeg", "-nostdin", "-hide_banner", "-i", str(path), "-af",
+               "ebur128=peak=true", "-f", "null", "-"]
+    result = subprocess.run(command, check=True, capture_output=True, text=True, timeout=30)
+    summary = result.stderr.rsplit("Summary:", 1)[1]
+    values = {
+        "integratedLUFS": float(re.search(r"I:\s+([-\d.]+) LUFS", summary)[1]),
+        "truePeakDBTP": float(re.search(r"Peak:\s+([-\d.]+) dBFS", summary)[1]),
+        "loudnessRangeLU": float(re.search(r"LRA:\s+([-\d.]+) LU", summary)[1]),
+        "thresholdLUFS": float(re.search(r"Threshold:\s+([-\d.]+) LUFS", summary)[1]),
+    }
+    if not all(math.isfinite(v) for v in values.values()):
+        raise ValueError("non-finite ebur128 measurement")
+    return values
+
+
+class FinalLoudness(unittest.TestCase):
+    """8 WAV의 동등성 assertion은 계기 불일치를 이유로 면제하지 않는다."""
+    @classmethod
+    def setUpClass(cls):
+        cls.rows = {p.stem: independent_measure(p) for p in sorted((ROOT / "public/ambience").glob("*.wav"))}
+
+    def test_final_wavs_meet_fixed_loudness_and_true_peak(self):
+        self.assertEqual(len(self.rows), 8)
+        spread = max(r["integratedLUFS"] for r in self.rows.values()) - min(r["integratedLUFS"] for r in self.rows.values())
+        print(json.dumps({"measurementFilter": "ebur128=peak=true", "targetLUFS": TARGET,
+                          "truePeakCeilingDBTP": CEILING, "spreadLU": round(spread, 2),
+                          "files": self.rows}, indent=2), flush=True)
+        for name, row in self.rows.items():
+            with self.subTest(environment=name):
+                self.assertLessEqual(abs(row["integratedLUFS"] - TARGET), 0.2 + 1e-9)
+                self.assertLessEqual(row["truePeakDBTP"], CEILING)
+        # 삭제되었던 ebur128 integrated 동등성 검사를 릴리스 필수 조건으로 복원한다.
+        self.assertLessEqual(spread, 0.4 + 1e-9)
+
+    def test_manifest_records_linear_gain_and_exact_ebur128_measurements(self):
+        manifest = json.loads((ROOT / "public/ambience/manifest.json").read_text())
+        settings = manifest["normalization"]
+        for key, value in {"targetIntegratedLUFS": TARGET, "truePeakCeilingDBTP": CEILING,
+                           "internalTruePeakCeilingDBTP": -6.2, "toleranceLU": 0.2,
+                           "maximumSpreadLU": 0.4, "measurementFilter": "ebur128=peak=true",
+                           "maximumIterations": 3}.items():
+            self.assertEqual(settings[key], value)
+        self.assertIn("ffmpeg version", manifest["toolVersions"]["ffmpeg"])
+        for entry in manifest["files"]:
+            norm = entry["conversion"]["loudness"]
+            self.assertEqual(norm["measurementFilter"], "ebur128=peak=true")
+            self.assertRegex(norm["fadedPcmSha256"], r"^[a-f0-9]{64}$")
+            self.assertGreaterEqual(len(norm["iterations"]), 1)
+            self.assertLessEqual(len(norm["iterations"]), 3)
+            gain = TARGET - norm["input"]["integratedLUFS"]
+            for iteration in norm["iterations"]:
+                self.assertAlmostEqual(iteration["gainDB"], gain, places=9)
+                self.assertEqual(iteration["filter"], f"volume={gain:.12f}dB:precision=double")
+                self.assertLessEqual(norm["input"]["truePeakDBTP"] + gain, -6.2 + 1e-9)
+                gain += TARGET - iteration["output"]["integratedLUFS"]
+            self.assertEqual(norm["final"], norm["iterations"][-1]["output"])
+            # manifest 수치는 새 프로세스 실측과 정확히 같아야 한다.
+            self.assertEqual(norm["final"], self.rows[entry["environmentId"]])
+            self.assertEqual(entry["sha256"], hashlib.sha256((ROOT / "public/ambience" / entry["file"]).read_bytes()).hexdigest())