Add pedal threshholding

.gitignore

@@ -160,3 +160,6 @@ cython_debug/
 #  and can be added to the global gitignore or merged into this file.  For a more nuclear
 #  option (not recommended) you can uncomment the following to ignore the entire idea folder.
 #.idea/
+
+tests/assets/results/
+uv.lock

ariautils/midi.py

@@ -382,14 +382,38 @@ def _tempo_at_tick(tick: int) -> int:
 
         return self
 
-    def apply_pedal_threshold(self, threshold: int = 64) -> "MidiDict":
-        """Apply a threshold to raw sustain pedal values in place."""
+    def apply_pedal_threshold(
+        self,
+        threshold: int = 64,
+        buffer: int = 0,
+        transitions_only: bool = False,
+    ) -> "MidiDict":
+        """Apply threshold hysteresis to raw sustain pedal values in place."""
 
         if threshold < 0 or threshold > 127:
             raise ValueError("threshold must be between 0 and 127")
+        if buffer < 0 or threshold - buffer < 0 or threshold + buffer > 127:
+            raise ValueError("buffer must keep thresholds between 0 and 127")
 
-        for pedal_msg in self.pedal_msgs:
-            pedal_msg["data"] = 1 if pedal_msg["value"] >= threshold else 0
+        pedal_state: dict[int, Literal[0, 1]] = {}
+        pedal_msgs = []
+        for pedal_msg in sorted(self.pedal_msgs, key=lambda msg: msg["tick"]):
+            channel = pedal_msg["channel"]
+            prev_data: Literal[0, 1] = pedal_state.get(channel, 0)
+
+            if pedal_msg["value"] >= threshold + buffer:
+                data: Literal[0, 1] = 1
+            elif pedal_msg["value"] <= threshold - buffer:
+                data = 0
+            else:
+                data = prev_data
+
+            pedal_msg["data"] = data
+            pedal_state[channel] = data
+            if not transitions_only or data != prev_data:
+                pedal_msgs.append(pedal_msg)
+
+        self.pedal_msgs = pedal_msgs
 
         return self
 

tests/test_midi.py

@@ -163,6 +163,54 @@ def test_apply_pedal_threshold(self) -> None:
         )
         self.assertEqual(midi_dict.note_msgs[0]["data"]["end"], 50)
 
+    def test_apply_pedal_threshold_buffer(self) -> None:
+        midi_dict = MidiDict.from_msg_dict(
+            {
+                "meta_msgs": [],
+                "tempo_msgs": [],
+                "pedal_msgs": [
+                    {
+                        "type": "pedal",
+                        "data": 0,
+                        "value": value,
+                        "tick": tick,
+                        "channel": 0,
+                    }
+                    for tick, value in enumerate(
+                        [0, 63, 72, 70, 57, 56, 65, 73, 60, 55]
+                    )
+                ],
+                "instrument_msgs": [],
+                "note_msgs": [
+                    {
+                        "type": "note",
+                        "data": {
+                            "pitch": 60,
+                            "start": 0,
+                            "end": 50,
+                            "velocity": 64,
+                        },
+                        "tick": 0,
+                        "channel": 0,
+                    }
+                ],
+                "ticks_per_beat": 480,
+                "metadata": {},
+            }
+        )
+
+        result = midi_dict.apply_pedal_threshold(
+            threshold=64, buffer=8, transitions_only=True
+        )
+
+        self.assertIs(result, midi_dict)
+        self.assertEqual(
+            [msg["tick"] for msg in midi_dict.pedal_msgs], [2, 5, 7, 9]
+        )
+        self.assertEqual(
+            [msg["data"] for msg in midi_dict.pedal_msgs], [1, 0, 1, 0]
+        )
+
     def test_resolve_pedal(self) -> None:
         load_path = TEST_DATA_DIRECTORY.joinpath("arabesque.mid")
         save_path = RESULTS_DATA_DIRECTORY.joinpath(