feat: add heal cut ffmpeg command

core/ffmpeg.py

@@ -314,6 +314,41 @@ def build_audio_delete_command(input_path: str, start: float, end: float,
             "-filter_complex", fc, "-map", "[out]", *codec, out_path]
 
 
+def _auto_heal_crossfade(start: float, end: float,
+                         requested: float | None = None) -> float:
+    if end <= start:
+        raise ValueError("heal delete end must be greater than start")
+    if requested is not None:
+        fade = max(0.0, float(requested))
+    else:
+        fade = min(0.25, max(0.04, (end - start) * 0.25))
+    # Without knowing total duration, clamp only to available pre-roll.
+    fade = min(fade, max(0.0, float(start)))
+    return round(fade, 3)
+
+
+def build_audio_heal_delete_command(input_path: str, start: float, end: float,
+                                    out_path: str,
+                                    crossfade: float | None = None) -> list[str]:
+    """Remove [start, end] and heal the join with a short equal-power crossfade."""
+    if end <= start:
+        raise ValueError("heal delete end must be greater than start")
+    s, e = round(start, 3), round(end, 3)
+    xf = _auto_heal_crossfade(s, e, crossfade)
+    ext = os.path.splitext(out_path)[1].lower()
+    codec = _AUDIO_CODEC_BY_EXT.get(ext, [])
+    if xf <= 0:
+        fc = (f"[0]atrim=end={s},asetpts=PTS-STARTPTS[a];"
+              f"[0]atrim=start={e},asetpts=PTS-STARTPTS[b];"
+              f"[a][b]concat=n=2:v=0:a=1[out]")
+    else:
+        fc = (f"[0]atrim=end={s},asetpts=PTS-STARTPTS[a];"
+              f"[0]atrim=start={e},asetpts=PTS-STARTPTS[b];"
+              f"[a][b]acrossfade=d={xf}:c1=qsin:c2=qsin[out]")
+    return [_bin("ffmpeg"), "-y", "-i", input_path,
+            "-filter_complex", fc, "-map", "[out]", *codec, out_path]
+
+
 def build_audio_silence_command(input_path: str, start: float, end: float,
                                 out_path: str) -> list[str]:
     """Silence the [start, end] region (volume=0 gated by an enable expr)."""

tests/test_utils.py

@@ -231,6 +231,42 @@ def test_audio_delete_empty_head():
     assert "atrim=end=0.0" in fc and "atrim=start=2.0" in fc
 
 
+def test_audio_heal_delete_command_crossfades_join():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 2.0, 4.0, "/o/o.wav", crossfade=0.1)
+    assert cmd[0] == "ffmpeg"
+    assert cmd.count("-i") == 1
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "atrim=end=2.0" in fc
+    assert "atrim=start=4.0" in fc
+    assert "acrossfade=d=0.1:c1=qsin:c2=qsin[out]" in fc
+    assert cmd[cmd.index("-map") + 1] == "[out]"
+    assert "pcm_s16le" in cmd
+    assert cmd[-1] == "/o/o.wav"
+
+
+def test_audio_heal_delete_command_auto_crossfade_clamped():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 10.0, 12.0, "/o/o.mp3")
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "acrossfade=d=0.25:c1=qsin:c2=qsin[out]" in fc
+    assert "libmp3lame" in cmd
+
+
+def test_audio_heal_delete_command_near_start_shortens_crossfade():
+    from core.ffmpeg import build_audio_heal_delete_command
+    cmd = build_audio_heal_delete_command("/in.wav", 0.03, 1.0, "/o/o.wav")
+    fc = cmd[cmd.index("-filter_complex") + 1]
+    assert "acrossfade=d=0.03:c1=qsin:c2=qsin[out]" in fc
+
+
+def test_audio_heal_delete_command_rejects_invalid_region():
+    import pytest
+    from core.ffmpeg import build_audio_heal_delete_command
+    with pytest.raises(ValueError):
+        build_audio_heal_delete_command("/in.wav", 3.0, 3.0, "/o/o.wav")
+
+
 # --- ProcessedDB ---
 
 def test_db_add_and_get_markers():