Add a VideoSlice node (#12107)

* Base TrimVideo implementation

* Raise error if as_trimmed call fails

* Bigger max start_time, tooltips, and formatting

* Count packets unless codec has subframes

* Remove incorrect nested decode

* Add null check for audio streams

* Support non-strict duration

* Added strict_duration bool to node definition

* Empty commit for approval

* Fix duration

* Support 5.1 audio layout on save

---------

Co-authored-by: Jedrzej Kosinski <kosinkadink1@gmail.com>

comfy_api/latest/_input/video_types.py

@@ -34,6 +34,21 @@ class VideoInput(ABC):
         """
         pass
 
+    @abstractmethod
+    def as_trimmed(
+        self,
+        start_time: float | None = None,
+        duration: float | None = None,
+        strict_duration: bool = False,
+    ) -> VideoInput | None:
+        """
+        Create a new VideoInput which is trimmed to have the corresponding start_time and duration
+
+        Returns:
+            A new VideoInput, or None if the result would have negative duration
+        """
+        pass
+
     def get_stream_source(self) -> Union[str, io.BytesIO]:
         """
         Get a streamable source for the video. This allows processing without