From e119f264354e8272067036574bd2222f34b07d2e Mon Sep 17 00:00:00 2001
From: ryan <rmmanseau@gmail.com>
Date: Wed, 6 Dec 2023 15:45:16 -0800
Subject: [PATCH] initial commit

---
 trim.py | 104 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 104 insertions(+)
 create mode 100755 trim.py

diff --git a/trim.py b/trim.py
new file mode 100755
index 0000000..ad71e77
--- /dev/null
+++ b/trim.py
@@ -0,0 +1,104 @@
+#!/usr/bin/env python3
+
+import argparse
+import cv2
+import moviepy.editor as mp
+
+MIN_INTERESTING_FRAMES = 20
+MOVEMENT_THRESHOLD = 1000
+
+def main():
+    # argparse
+    parser = argparse.ArgumentParser()
+    parser.add_argument('filename')
+    args = parser.parse_args()
+
+    # get video info
+    vid = cv2.VideoCapture(args.filename)
+    ret, colorFrame = vid.read()
+    frame = cv2.cvtColor(colorFrame, cv2.COLOR_BGR2GRAY)
+    fps = vid.get(cv2.CAP_PROP_FPS)
+    fnum = int(vid.get(cv2.CAP_PROP_FRAME_COUNT))
+    dur = fnum // fps
+    print("video stats: \n"
+          f"fps:    {fps}\n"
+          f"frames: {fnum}\n"
+          f"length: {int(dur//60):02}:{int(dur%60):02}\n")
+
+    # prepare to find interesting segments
+    print("finding interesting segments ...")
+    i = 0
+    clips = []
+    startFrame = 0
+    inSegment = False
+
+    # start a segment if we aren't already in one.
+    def maybeStartSegment(i):
+        nonlocal inSegment, startFrame
+        if inSegment == False:
+            inSegment = True
+            startFrame = i
+            print( f"found one! frame {i:8} to ... ", end="", flush=True)
+
+    # end a segment if we are in one, and then save the
+    # start and end frames if it was a long enough segment
+    def maybeEndSegment(i):
+        nonlocal inSegment
+        if inSegment == True:
+            inSegment = False
+            if i - startFrame > MIN_INTERESTING_FRAMES:
+                print( f"{i:6} ! ")
+                clips.append((startFrame, i))
+            else:
+                print( f"nvm, too short.")
+
+    # loop through each frame
+    while(True):
+        i += 1;
+        ret, colorFrame = vid.read()
+
+        # if theres no more frames, break the loop &
+        # maybe end the current segment
+        if not ret:
+            maybeEndSegment(i)
+            break;
+
+        # calculate the difference between the current & last frame
+        # then run the Canny algorithm to find edges within the
+        # diff. edges in the diff indicate that something is moving
+        # in the frame.
+        prev = frame
+        frame = cv2.cvtColor(colorFrame, cv2.COLOR_BGR2GRAY)
+        diff = cv2.subtract(frame, prev)
+        edges = cv2.Canny(diff, 100, 200)
+
+        # number of non zero (not true block) pixels in the edge frame.
+        # large number indicates edges which indicates movment.
+        nz = cv2.countNonZero(edges)
+
+        if nz > MOVEMENT_THRESHOLD:
+            maybeStartSegment(i)
+        else:
+            maybeEndSegment(i)
+
+    # finished looping
+    vid.release()
+    print("done! time to chop up the video :) ")
+
+    # convert the segment indicators from frame number to seconds
+    def frame2second(f):
+        return round(f / fps, 2)
+    clipsSeconds = [ (frame2second(x),frame2second(y)) for (x,y) in clips ]
+    print( clipsSeconds )
+
+    # slice that bitch up & export it!
+    movie = mp.VideoFileClip(args.filename)
+    clips = [ movie.subclip(s, e) for (s,e) in clipsSeconds ]
+    trimmed = mp.concatenate_videoclips(clips)
+    out_filename = args.filename.replace('.mp4', '') + '_trimmed.mp4'
+    trimmed.write_videofile(out_filename)
+
+    print("enjoy!")
+
+if __name__ == "__main__":
+    main();