Improved corrupt frame handling

camdetect.py

@@ -376,26 +376,28 @@ async def download(resp, queue):
                 blob = buf + data[:marker+2]
 
                 # Parse DCT coefficients
-                dct = loads(blob)
-
-                now = datetime.utcnow()
-                gauge_last_frame.labels("download").set(now.timestamp())
                 try:
-                    # Convert Y component to 16 bit for easier handling
-                    queue.put_nowait((
-                        now,
-                        blob,
-                        dct,
-                        generate_thumbnail(dct)))
-                except asyncio.QueueFull:
-                    counter_dropped_frames.labels("download").inc()
-                gauge_queue_frames.labels("download").set(queue.qsize())
+                    dct = loads(blob)
+                except RuntimeError:
+                    counter_frames.labels("corrupted").inc()
+                else:
+                    now = datetime.utcnow()
+                    gauge_last_frame.labels("download").set(now.timestamp())
+                    try:
+                        queue.put_nowait((
+                            now,
+                            blob,
+                            dct,
+                            generate_thumbnail(dct)))
+                    except asyncio.QueueFull:
+                        counter_dropped_frames.labels("download").inc()
+                    gauge_queue_frames.labels("download").set(queue.qsize())
                 data = data[marker+2:]
                 buf = b""
                 counter_receive_frames.inc()
 
         # seek begin
-        marker = data.find(b"\xff\xd8")
+        marker = data.rfind(b"\xff\xd8")
         if marker >= 0:
             buf = data[marker:]
         else: