Add set_image for updating the image content of an existing frame

Author: daveisfera

av/video/frame.py

@@ -610,16 +610,22 @@ def to_ndarray(self, channel_last=False, **kwargs):
             f"Conversion to numpy array with format `{frame.format.name}` is not yet supported"
         )
 
-    @staticmethod
-    def from_image(img):
+    def set_image(self, img):
         """
-        Construct a frame from a ``PIL.Image``.
+        Update content from a ``PIL.Image``.
         """
         if img.mode != "RGB":
             img = img.convert("RGB")
 
+        copy_array_to_plane(img, self.planes[0], 3)
+
+    @staticmethod
+    def from_image(img):
+        """
+        Construct a frame from a ``PIL.Image``.
+        """
         frame: VideoFrame = VideoFrame(img.size[0], img.size[1], "rgb24")
-        copy_array_to_plane(img, frame.planes[0], 3)
+        frame.set_image(img)
 
         return frame