diff --git a/alembic/versions/backfill_song_metadata.py b/alembic/versions/backfill_song_metadata.py
new file mode 100644
index 0000000..e53fdb1
--- /dev/null
+++ b/alembic/versions/backfill_song_metadata.py
@@ -0,0 +1,51 @@
+"""Backfill song metadata
+
+Revision ID: backfill_song_metadata
+Revises: 03e6e9292a46
+Create Date: 2024-12-01 12:00:00.000000
+
+"""
+from typing import Sequence, Union
+
+from alembic import op
+import sqlalchemy as sa
+from sqlalchemy.orm import Session
+from rainfall.models.file import File
+from rainfall.db import db
+import os
+import mutagen
+from rainfall.site import release_path, secure_filename
+
+# revision identifiers, used by Alembic.
+revision: str = 'backfill_song_metadata'
+down_revision: Union[str, None] = '03e6e9292a46'
+branch_labels: Union[str, Sequence[str], None] = None
+depends_on: Union[str, Sequence[str], None] = None
+
+
+def upgrade() -> None:
+  bind = op.get_context().bind
+  session = Session(bind)
+  data_dir = os.environ.get('DATA_DIR', 'data')
+
+  for f in session.query(File).all():
+    try:
+      release = f.release
+      if not release or not release.site:
+        continue
+      file_path = os.path.join(release_path(data_dir, release.site), secure_filename(f.filename))
+      audio = mutagen.File(file_path, easy=False)
+      if audio is None:
+        continue
+      f.duration = float(audio.info.length)
+      f.bitrate = audio.info.bitrate or 0
+      f.sample_rate = audio.info.sample_rate or 0
+      f.channels = audio.info.channels or 0
+      session.commit()
+    except Exception as e:
+      session.rollback()
+      print(f'Failed to backfill metadata for {f.filename}: {e}')
+
+
+def downgrade() -> None:
+  pass