diff --git a/cista/preview.py b/cista/preview.py
index bf9eb2d..2b20a97 100644
--- a/cista/preview.py
+++ b/cista/preview.py
@@ -10,7 +10,6 @@ from wsgiref.handlers import format_date_time
 import av
 import av.datasets
 import fitz  # PyMuPDF
-from av.streams import SideData
 from PIL import Image
 from sanic import Blueprint, empty, raw
 from sanic.exceptions import NotFound
@@ -19,6 +18,8 @@ from sanic.log import logger
 from cista import config
 from cista.util.filename import sanitize
 
+DISPLAYMATRIX = av.streams.SideData.DISPLAYMATRIX
+
 bp = Blueprint("preview", url_prefix="/preview")
 
 
@@ -100,7 +101,7 @@ def process_video(path, *, maxsize, quality):
         stream = container.streams.video[0]
         stream.codec_context.skip_frame = "NONKEY"
         stream.codec_context.threads = 1
-        rot = stream.side_data and stream.side_data.get(SideData.DISPLAYMATRIX) or 0
+        rot = stream.side_data and stream.side_data.get(DISPLAYMATRIX) or 0
         container.seek(container.duration // 8)
         img = next(container.decode(stream)).to_image()
         del stream