feat: add lyrics plugin

lyrics/krc_decode.py

@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+# Decode NetEase KRC ("klyric") dynamic lyrics into per-character timings.
+# Reads the klyric field (base64 of "krc1" + zlib stream) from argv[1],
+# writes JSON: {"type":"krc","lines":[{"time":ms,"text":"...","chars":[ms,...]}]}
+import sys, json, base64, zlib, re
+
+def find_zlib(buf):
+    for i in range(len(buf) - 1):
+        if buf[i] == 0x78 and buf[i + 1] in (0x01, 0x9c, 0xda):
+            try:
+                return zlib.decompress(buf[i:])
+            except Exception:
+                continue
+    return None
+
+def decode_krc(raw):
+    if isinstance(raw, str) and re.search(r"^\[\d+,\d+\]", raw, re.MULTILINE):
+        return raw
+    data = None
+    if isinstance(raw, str):
+        try:
+            data = base64.b64decode(raw)
+        except Exception:
+            data = raw.encode("latin-1")
+    else:
+        data = raw
+    if data[:4] == b"krc1":
+        data = data[4:]
+    dec = find_zlib(data)
+    if dec is None:
+        return None
+    try:
+        return dec.decode("utf-8")
+    except Exception:
+        return dec.decode("utf-8", "ignore")
+
+LINE_RE = re.compile(r"^\[(\d+),(\d+)\](.*)$")
+PREFIX_SYL_RE = re.compile(r"(?:<|\()(\d+),(\d+)(?:,\d+)?(?:>|\))([^<(]*)")
+SUFFIX_SYL_RE = re.compile(r"(.*?)<(\d+),(\d+)(?:,\d+)?>")
+
+def parse_krc(text):
+    out = []
+    for line in text.splitlines():
+        m = LINE_RE.match(line)
+        if not m:
+            continue
+        start = int(m.group(1))
+        dur = int(m.group(2))
+        body = m.group(3)
+        # NetEase has shipped both `(offset,duration,0)word` and
+        # `word<offset,duration>` variants of its word-synced format.
+        prefixed = PREFIX_SYL_RE.findall(body) if re.match(r"^[<(]\d+,", body) else []
+        if prefixed:
+            syl = [(word, int(offset), int(duration))
+                   for offset, duration, word in prefixed]
+        else:
+            syl = [(word, int(offset), int(duration))
+                   for word, offset, duration in SUFFIX_SYL_RE.findall(body)]
+        if not syl and body.strip() != "":
+            syl = [(body, 0, dur)]
+        chars = []
+        full = ""
+        for (word, so, sd) in syl:
+            n = len(word)
+            if n == 0:
+                continue
+            for j in range(n):
+                chars.append(start + so + (j * sd) // n)
+                full += word[j]
+        if full.strip() != "":
+            out.append({"time": start, "duration": dur, "text": full, "chars": chars})
+    return out
+
+def main():
+    if len(sys.argv) < 2:
+        print(json.dumps({"type": "none"}))
+        return
+    try:
+        with open(sys.argv[1], "r", encoding="utf-8") as f:
+            raw = f.read()
+    except Exception:
+        print(json.dumps({"type": "none"}))
+        return
+    text = decode_krc(raw)
+    if text is None:
+        print(json.dumps({"type": "none"}))
+        return
+    print(json.dumps({"type": "krc", "lines": parse_krc(text)}, ensure_ascii=False))
+
+if __name__ == "__main__":
+    main()