adjust formula for vocaloid portamento

libresvip/model/pitch_simulator.py

@@ -24,15 +24,15 @@ def __post_init__(self, note_list: list[Note]) -> None:  # type: ignore[override
             return
         current_note = note_list[0]
         max_portamento_percent = self.portamento.max_inter_time_percent
-        if self.portamento.vocaloid_mode:  # reference: https://github.com/scskarsper/VocalUtau.Formats/blob/master/VocalUtau.Formats/Model.VocalObject/ParamTranslater/PitchCompiler.cs
+        if self.portamento.vocaloid_mode:
             max_portamento_ticks = max_portamento_percent * current_note.length
             if max_portamento_ticks >= 60:
                 max_portamento_ticks = 60
             elif current_note.length <= 120:
                 max_portamento_ticks = current_note.length / 2
             max_portamento_time = self.synchronizer.get_duration_secs_from_ticks(
-                int(current_note.end_pos - max_portamento_ticks * 1.5),
-                int(current_note.end_pos - max_portamento_ticks * 0.5),
+                int(current_note.end_pos - max_portamento_ticks * 1.4),
+                int(current_note.end_pos - max_portamento_ticks * 0.4),
             )
         else:
             max_portamento_time = self.portamento.max_inter_time_in_secs
@@ -49,6 +49,10 @@ def __post_init__(self, note_list: list[Note]) -> None:  # type: ignore[override
             if current_note.end_pos > next_note.start_pos:
                 msg = _("Notes Overlapped")
                 raise NotesOverlappedError(msg)
+            elif (
+                self.portamento.vocaloid_mode and next_note.start_pos - current_note.end_pos >= 480
+            ):
+                max_portamento_time = 0
             next_head = self.synchronizer.get_actual_secs_from_ticks(next_note.start_pos)
             next_dur = self.synchronizer.get_duration_secs_from_ticks(
                 next_note.start_pos, next_note.end_pos
@@ -59,7 +63,7 @@ def __post_init__(self, note_list: list[Note]) -> None:  # type: ignore[override
                     current_note.end_pos
                     if next_note.lyric == "-"
                     else (next_note.start_pos + current_note.end_pos) / 2
-                ) - max_portamento_ticks / 2
+                ) - max_portamento_ticks * 0.4
                 interval = self.synchronizer.get_duration_secs_from_ticks(
                     int(middle_pos - max_portamento_ticks), int(middle_pos)
                 )
@@ -100,8 +104,8 @@ def __post_init__(self, note_list: list[Note]) -> None:  # type: ignore[override
                 elif current_note.length <= 120:
                     max_portamento_ticks = current_note.length / 2
                 max_portamento_time = self.synchronizer.get_duration_secs_from_ticks(
-                    int(middle_pos - max_portamento_ticks * 1.5),
-                    int(middle_pos - max_portamento_ticks * 0.5),
+                    int(middle_pos - max_portamento_ticks * 1.4),
+                    int(middle_pos - max_portamento_ticks * 0.4),
                 )
         self.interval_dict[portion.closedopen(prev_portamento_end, portion.inf)] = (
             current_note.key_number

libresvip/model/portamento.py

@@ -9,6 +9,7 @@
     cubic_interpolation,
     linear_interpolation,
     sigmoid_interpolation,
+    vocaloid_interpolation,
 )
 
 if TYPE_CHECKING:
@@ -40,4 +41,4 @@ def sigmoid_portamento(cls) -> PortamentoPitch:
 
     @classmethod
     def vocaloid_portamento(cls) -> PortamentoPitch:
-        return cls(0.05, 0.15, cosine_easing_in_out_interpolation, True)
+        return cls(0.05, 0.15, vocaloid_interpolation, True)

libresvip/utils/music_math.py

@@ -118,6 +118,15 @@ def cubic_interpolation(r: float) -> float:
     return (3 - 2 * r) * r**2
 
 
+@_transform_interpolation_args
+def vocaloid_interpolation(r: float) -> float:
+    if r <= 0.5:
+        return math.sin(r * math.pi) / 2
+    else:
+        return r
+    # math.sin((r - 1) * math.pi) / 2 + 1
+
+
 @_transform_interpolation_args  # type: ignore[arg-type]
 def sigmoid_interpolation(r: float, k: float) -> float:
     return 1 / (1 + math.exp(k * (-2 * r + 1)))