Merge pull request #151 from mhashim6/live_callback

live callbacks for live-streams.

Resolves #5.

Author: Breakthrough

docs/changelog.md

@@ -17,6 +17,7 @@ PySceneDetect Releases
  * [enhancement] Removed first row from statsfile to comply with RFC 4180, includes backwards compatibility so existing statsfiles can still be loaded (resolves [#136](https://github.com/Breakthrough/PySceneDetect/issues/136))
  * [api] Removed unused argument base_timecode from `StatsManager.load_from_csv()` method
  * [api] Make the `base_timecode` argument optional on the `SceneManager` methods `get_scene_list()`, `get_cut_list()`, and `get_event_list()` (resolves [#173](https://github.com/Breakthrough/PySceneDetect/issues/173))
+ * [api] Support for live video stream callbacks by adding new `callback` argument to the `detect_scenes()` method of `SceneManager` (resolves [#5](https://github.com/Breakthrough/PySceneDetect/issues/5))
  * [bugfix] Fix unhandled exception causing improper error message when a video fails to load on non-Windows platforms (resolves [#192](https://github.com/Breakthrough/PySceneDetect/issues/192))
  * [enhancement] Enabled dynamic resizing for progress bar (resolves [#193](https://github.com/Breakthrough/PySceneDetect/issues/193))
  * [enhancement] Always ouptut version number via logger to assist with debugging (resolves [#171](https://github.com/Breakthrough/PySceneDetect/issues/171))

scenedetect/scene_manager.py

@@ -505,13 +505,19 @@ def get_event_list(self, base_timecode=None):
                 for start, end in self._event_list]
 
 
-    def _process_frame(self, frame_num, frame_im):
+    def _process_frame(self, frame_num, frame_im, callback=None):
         # type(int, numpy.ndarray) -> None
         """ Adds any cuts detected with the current frame to the cutting list. """
         for detector in self._detector_list:
-            self._cutting_list += detector.process_frame(frame_num, frame_im)
+            cuts = detector.process_frame(frame_num, frame_im)
+            if cuts and callback:
+                callback(frame_im, frame_num)
+            self._cutting_list += cuts
         for detector in self._sparse_detector_list:
-            self._event_list += detector.process_frame(frame_num, frame_im)
+            events = detector.process_frame(frame_num, frame_im)
+            if events and callback:
+                callback(frame_im, frame_num)
+            self._event_list += events
 
 
     def _is_processing_required(self, frame_num):
@@ -530,9 +536,9 @@ def _post_process(self, frame_num):
 
 
     def detect_scenes(self, frame_source, end_time=None, frame_skip=0,
-                      show_progress=True):
+                      show_progress=True, callback=None):
         # type: (VideoManager, Union[int, FrameTimecode],
-        #        Optional[Union[int, FrameTimecode]], Optional[bool]) -> int
+        #        Optional[Union[int, FrameTimecode]], Optional[bool], optional[callable[numpy.ndarray]) -> int
         """ Perform scene detection on the given frame_source using the added SceneDetectors.
 
         Blocks until all frames in the frame_source have been processed. Results can
@@ -554,6 +560,8 @@ def detect_scenes(self, frame_source, end_time=None, frame_skip=0,
             show_progress (bool): If True, and the ``tqdm`` module is available, displays
                 a progress bar with the progress, framerate, and expected time to
                 complete processing the video frame source.
+            callback ((image_ndarray, frame_num: int) -> None): If not None, called after
+                each scene/event detected.
         Returns:
             int: Number of frames read and processed from the frame source.
         Raises:
@@ -618,7 +626,7 @@ def detect_scenes(self, frame_source, end_time=None, frame_skip=0,
 
                 if not ret_val:
                     break
-                self._process_frame(self._num_frames + start_frame, frame_im)
+                self._process_frame(self._num_frames + start_frame, frame_im, callback)
 
                 curr_frame += 1
                 self._num_frames += 1