Refacto of the scene cut detection, make it generic and add another algorythm as an option

scene_cut_detection.py

@@ -0,0 +1,148 @@
+import os
+import re
+import subprocess
+
+import bpy
+
+from vse_toolbox import bl_utils
+
+
+def detect_scene_change(strip, movie_type="ANIMATED", threshold=0.5, frame_start=None, frame_end=None, crop=None):
+    """Launch ffmpeg command to detect changing frames from a movie strip.
+
+    Args:
+        movie_strip (bpy.types.Sequence): blender sequence strip to detect changes.
+        threshold (float): value of the detection factor (from 0 to 1).
+        frame_start (int, optional): first frame to detect.
+            Defaults to None.
+        frame_end (int, optional): last frame to detect.
+            Defaults to None.
+
+    Returns:
+        str: ffmpeg command log.
+    """
+
+    path = bl_utils.abspath(strip.filepath)
+    fps = bpy.context.scene.render.fps
+
+    if frame_start is None:
+        frame_start = 0
+    if frame_end is None:
+        frame_end = strip.frame_duration
+
+    frame_start = frame_start - strip.frame_start
+
+    start_time = frame_start/fps
+    end_time = frame_end/fps
+
+    #frame_start += strip.frame_offset_start
+    #frame_end -= strip.frame_offset_end
+    
+    if movie_type == 'ANIMATED':
+        return select_generator(path, start_time=start_time, end_time=end_time, threshold=threshold, crop=crop)
+    
+    elif movie_type == 'STILL':
+        return freeze_detect_generator(path, start_time=start_time, end_time=end_time, threshold=threshold, crop=crop)
+    
+    else:
+        raise Exception(f'movie_type: {movie_type} not implemented')
+
+
+def freeze_detect_generator(path, start_time, end_time, threshold=0.005, crop=None):
+    """Generate the ffmpeg command which detect change from a movie. 
+
+    Args:
+        path (_type_): path to detect changes.
+        threshold (_type_): value of the detection factor (from 0 to 1).
+        frame_start (_type_): first frame to detect.
+        frame_end (_type_): last frame to detect.
+        fps (_type_): framerate of the movie.
+
+    Returns:
+        list: ffmpeg command as list for subprocess module.
+    """
+
+    if crop is None:
+        crop = [0, 0, 0, 0]
+
+    crop_expr = f"crop=iw-{crop[0]}-{crop[1]}:ih-{crop[2]}-{crop[3]}:{crop[0]}:{crop[-1]}"
+
+    command = [
+            'ffmpeg',
+            '-nostats',
+            '-i',
+            str(path),
+            '-ss', str(start_time),
+            '-t', str(end_time),
+            '-vf',
+            f"{crop_expr}, freezedetect=n={threshold}:d=0.01,metadata=print", #,
+            '-f',
+            'null',
+            '-'
+            ]
+    
+    print(command)
+
+    process = subprocess.Popen(
+        command,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        universal_newlines=True)
+    
+    def parse_split_time(log):
+        print(log)
+        timecodes = re.findall(r'freeze_end: ([\d.]+)', log)
+        if timecodes:
+            return round(float(timecodes[0]) * bpy.context.scene.render.fps)
+
+    return filter(None, (parse_split_time(x) for x in process.stdout))
+
+def select_generator(path, start_time, end_time, threshold, crop=None):
+    """Generate the ffmpeg command which detect change from a movie. 
+
+    Args:
+        path (_type_): path to detect changes.
+        threshold (_type_): value of the detection factor (from 0 to 1).
+        frame_start (_type_): first frame to detect.
+        frame_end (_type_): last frame to detect.
+        fps (_type_): framerate of the movie.
+
+    Returns:
+        list: ffmpeg command as list for subprocess module.
+    """
+
+    if crop is None:
+        crop = [0, 0, 0, 0]
+
+    crop_expr = f"crop=iw-{crop[0]}-{crop[1]}:ih-{crop[2]}-{crop[3]}:{crop[0]}:{crop[-1]}"
+
+    command = [
+            'ffmpeg',
+            '-nostats',
+            '-i',
+            str(path),
+            '-ss', str(start_time),
+            '-t', str(end_time),
+            '-vf',
+            f"{crop_expr}, select='gt(scene, {threshold})', showinfo",
+            '-f',
+            'null',
+            '-'
+            ]
+
+    print(command)
+
+    process = subprocess.Popen(
+        command,
+        stdout=subprocess.PIPE,
+        stderr=subprocess.STDOUT,
+        universal_newlines=True)
+        
+    def parse_split_time(log):
+        print(log)
+        timecodes = re.findall(r'pts_time:([\d.]+)', log)
+        if timecodes:
+            return round(float(timecodes[0]) * bpy.context.scene.render.fps)
+
+    return filter(None, (parse_split_time(x) for x in process.stdout))
+