D2: LimiterFx brickwall — lookahead 1-5ms + oversample 4x + hard clip, UI toggle SOFT/BRICKWALL + LOOKAHEAD ms

tests/test_daw_phase5.py

@@ -481,3 +481,50 @@ def test_57_master_chain_imager_maximizer_vst3(monkeypatch, tmp_path, fx_bridge,
     assert base > 0.001, "pan tạo side content"
     assert s0 < 0.05 * base, f"imager w=0 không giết side: {s0:.5f} vs {base:.5f}"
     assert s2 > 1.5 * base, f"imager w=200 không tăng side: {s2:.5f} vs {base:.5f}"
+
+def test_59_limiter_brickwall_oversample(fx_bridge):
+    """D2: LimiterFx mode brickwall — lookahead + oversample 4x + hard clip.
+    Impulse 0dB qua ceiling -1dB: peak <= ceiling + 0.005, length giu nguyen;
+    soft mode giu tanh (peak ~1.0); low-level qua brickwall ~ unity."""
+    n = 4096
+    imp = np.zeros(n, dtype=np.float32)
+    imp[512] = 1.0
+    audio = np.stack([imp, imp * 0.8]).astype(np.float32)
+    ceil_lin = 10.0 ** (-1.0 / 20.0)
+
+    brick = [{"type": "builtin", "id": "limiter",
+              "params": {"ceiling": -1.0, "mode": 1, "lookahead_ms": 2.0}}]
+    brick_str = [{"type": "builtin", "id": "limiter",
+                  "params": {"ceiling": -1.0, "mode": "brickwall", "lookahead_ms": 3.0}}]
+    soft = [{"type": "builtin", "id": "limiter",
+             "params": {"ceiling": -1.0}}]
+
+    with tempfile.TemporaryDirectory() as td:
+        wav_in = os.path.join(td, "in.wav")
+        _write_wav(wav_in, audio, SR)
+        out_brick = _render_bridge(fx_bridge, wav_in, SR, brick, block=512)
+        out_brick_str = _render_bridge(fx_bridge, wav_in, SR, brick_str, block=512)
+        out_soft = _render_bridge(fx_bridge, wav_in, SR, soft, block=512)
+
+    assert out_brick.shape == audio.shape, "brickwall length giu nguyen"
+    pk = float(np.max(np.abs(out_brick)))
+    assert pk <= ceil_lin + 0.005, f"brickwall peak {pk:.4f} > ceiling {ceil_lin:.4f}"
+    assert pk >= 0.70, f"brickwall khong giam dinh? peak {pk:.4f}"
+
+    pk_str = float(np.max(np.abs(out_brick_str)))
+    assert pk_str <= ceil_lin + 0.005, f"mode string peak {pk_str:.4f}"
+
+    pk_soft = float(np.max(np.abs(out_soft)))
+    assert pk_soft > 0.95, f"soft peak {pk_soft:.4f} (tanh normalized ~1.0)"
+    assert pk_soft <= 1.0005, f"soft peak {pk_soft:.4f} vuot 1.0"
+
+    imp2 = np.zeros(n, dtype=np.float32)
+    imp2[2048] = 0.1
+    audio2 = np.stack([imp2, imp2]).astype(np.float32)
+    with tempfile.TemporaryDirectory() as td:
+        wav_in2 = os.path.join(td, "in2.wav")
+        _write_wav(wav_in2, audio2, SR)
+        out_low = _render_bridge(fx_bridge, wav_in2, SR, brick, block=512)
+    pk_low = float(np.max(np.abs(out_low)))
+    assert 0.05 <= pk_low <= 0.15, f"low-level peak {pk_low:.4f} lech unity"
+