add test file for fades

archive/play.py

@@ -0,0 +1,42 @@
+#!/usr/bin/env python
+
+from pydub import AudioSegment
+
+
+def fade_point(audio_segment, fade_threshold=-12, chunk_size=10):
+    """
+    Returns the millisecond/index of the point where the fade is down to
+    fade_threshold and doesn't get louder again.
+    audio_segment - the sdlg_search_database_uiegment to find silence in
+    fade_threshold - the upper bound for how quiet is silent in dFBS
+    chunk_size - chunk size for interating over the segment in ms
+    """
+
+    assert chunk_size > 0  # to avoid infinite loop
+
+    segment_length = audio_segment.duration_seconds * 1000  # ms
+    print(f"segment_length={int(segment_length/1000)}")
+    trim_ms = segment_length - chunk_size
+
+    max_vol = audio_segment.dBFS
+    print(f"{max_vol=}")
+    fade_threshold = max_vol
+    while (
+        audio_segment[trim_ms:trim_ms + chunk_size].dBFS < fade_threshold
+            and trim_ms > 0):       # noqa W503
+        trim_ms -= chunk_size
+
+    # if there is no trailing silence, return lenght of track (it's less
+    # the chunk_size, but for chunk_size = 10ms, this may be ignored)
+    print(f"Fade last {int(segment_length - trim_ms)/1000} seconds")
+
+
+print("Shout:")
+segment = AudioSegment.from_mp3("../archive/shout.mp3")
+fade_point(segment)
+print("Champagne:")
+segment = AudioSegment.from_mp3("../archive/champ.mp3")
+fade_point(segment)
+print("Be good:")
+segment = AudioSegment.from_mp3("../archive/wibg.mp3")
+fade_point(segment)