Fix running with today's Python tooling and av module.

cista/preview.py

@@ -18,8 +18,6 @@ from sanic.log import logger
 from cista import config
 from cista.util.filename import sanitize
 
-DISPLAYMATRIX = av.stream.SideData.DISPLAYMATRIX
-
 bp = Blueprint("preview", url_prefix="/preview")
 
 
@@ -100,15 +98,39 @@ def process_video(path, *, maxsize, quality):
     with av.open(str(path)) as container:
         stream = container.streams.video[0]
         stream.codec_context.skip_frame = "NONKEY"
-        rot = stream.side_data and stream.side_data.get(DISPLAYMATRIX) or 0
+
+        # Updated side data access for newer av versions
+        rot = 0
+        try:
+            # Try newer API first
+            if hasattr(stream, "side_data") and stream.side_data:
+                display_matrix = stream.side_data.get("DISPLAYMATRIX")
+                if display_matrix:
+                    rot = (
+                        display_matrix.rotation
+                        if hasattr(display_matrix, "rotation")
+                        else 0
+                    )
+        except (AttributeError, KeyError):
+            # Fallback for older API or missing side data
+            rot = 0
+
         container.seek(container.duration // 8)
-        img = next(container.decode(stream)).to_image()
+        try:
+            frame = next(container.decode(stream))
+            img = frame.to_image()
+        except StopIteration:
+            # If no frame found, try from beginning
+            container.seek(0)
+            frame = next(container.decode(stream))
+            img = frame.to_image()
+
         del stream
 
     img.thumbnail((maxsize, maxsize))
     imgdata = io.BytesIO()
-    if rot:
-        img = img.rotate(rot, expand=True)
+    if rot and rot != 0:
+        img = img.rotate(-rot, expand=True)  # Negative rotation for correct orientation
     img.save(imgdata, format="webp", quality=quality, method=4)
     del img
     ret = imgdata.getvalue()