audio-key: truncate at 5min + mojibake support

bin/mtag/audio-key-slicing.py

@@ -0,0 +1,123 @@
+#!/usr/bin/env python
+
+import re
+import os
+import sys
+import tempfile
+import subprocess as sp
+
+import keyfinder
+
+from copyparty.util import fsenc
+
+"""
+dep: github/mixxxdj/libkeyfinder
+dep: pypi/keyfinder
+dep: ffmpeg
+
+note: this is a janky edition of the regular audio-key.py,
+  slicing the files at 20sec intervals and keeping 5sec from each,
+  surprisingly accurate but still garbage (446 ok, 69 bad, 13% miss)
+
+  it is fast tho
+"""
+
+
+def get_duration():
+    # TODO provide ffprobe tags to mtp as json
+
+    # fmt: off
+    dur = sp.check_output([
+        "ffprobe",
+        "-hide_banner",
+        "-v", "fatal",
+        "-show_streams",
+        "-show_format",
+        fsenc(sys.argv[1])
+    ])
+    # fmt: on
+
+    dur = dur.decode("ascii", "replace").split("\n")
+    dur = [x.split("=")[1] for x in dur if x.startswith("duration=")]
+    dur = [float(x) for x in dur if re.match(r"^[0-9\.,]+$", x)]
+    return list(sorted(dur))[-1] if dur else None
+
+
+def get_segs(dur):
+    # keep first 5s of each 20s,
+    # keep entire last segment
+    ofs = 0
+    segs = []
+    while True:
+        seg = [ofs, 5]
+        segs.append(seg)
+        if dur - ofs < 20:
+            seg[-1] = int(dur - seg[0])
+            break
+
+        ofs += 20
+
+    return segs
+
+
+def slice(tf):
+    dur = get_duration()
+    dur = min(dur, 600)  # max 10min
+    segs = get_segs(dur)
+
+    # fmt: off
+    cmd = [
+        "ffmpeg",
+        "-nostdin",
+        "-hide_banner",
+        "-v", "fatal",
+        "-y"
+    ]
+
+    for seg in segs:
+        cmd.extend([
+            "-ss", str(seg[0]),
+            "-i", fsenc(sys.argv[1])
+        ])
+    
+    filt = ""
+    for n, seg in enumerate(segs):
+        filt += "[{}:a:0]atrim=duration={}[a{}]; ".format(n, seg[1], n)
+    
+    prev = "a0"
+    for n in range(1, len(segs)):
+        nxt = "b{}".format(n)
+        filt += "[{}][a{}]acrossfade=d=0.5[{}]; ".format(prev, n, nxt)
+        prev = nxt
+
+    cmd.extend([
+        "-filter_complex", filt[:-2],
+        "-map", "[{}]".format(nxt),
+        "-sample_fmt", "s16",
+        tf
+    ])
+    # fmt: on
+
+    # print(cmd)
+    sp.check_call(cmd)
+
+
+def det(tf):
+    slice(tf)
+    print(keyfinder.key(tf).camelot())
+
+
+def main():
+    with tempfile.NamedTemporaryFile(suffix=".flac", delete=False) as f:
+        f.write(b"h")
+        tf = f.name
+
+    try:
+        det(tf)
+    finally:
+        os.unlink(tf)
+        pass
+
+
+if __name__ == "__main__":
+    main()