Implement simple frame cache

croppa/main.py

@@ -12,6 +12,7 @@ import json
 import subprocess
 import queue
 import ctypes
+from collections import OrderedDict
 from PIL import Image
 
 def load_image_utf8(image_path):
@@ -279,7 +280,7 @@ class FeatureTracker:
 class Cv2BufferedCap:
     """Buffered wrapper around cv2.VideoCapture that handles frame loading, seeking, and caching correctly"""
     
-    def __init__(self, video_path, backend=None):
+    def __init__(self, video_path, backend=None, cache_size=10000):
         self.video_path = video_path
         self.cap = cv2.VideoCapture(str(video_path), backend)
         if not self.cap.isOpened():
@@ -294,6 +295,10 @@ class Cv2BufferedCap:
         # Current position tracking
         self.current_frame = 0
         
+        # Frame cache (LRU)
+        self.cache_size = cache_size
+        self.frame_cache = OrderedDict()
+        
     
     
     def get_frame(self, frame_number):
@@ -301,6 +306,11 @@ class Cv2BufferedCap:
         # Clamp frame number to valid range
         frame_number = max(0, min(frame_number, self.total_frames - 1))
         
+        # Check cache first
+        if frame_number in self.frame_cache:
+            self.frame_cache.move_to_end(frame_number)
+            return self.frame_cache[frame_number]
+        
         # Optimize for sequential reading (next frame)
         if frame_number == self.current_frame + 1:
             ret, frame = self.cap.read()
@@ -311,6 +321,11 @@ class Cv2BufferedCap:
         
         if ret:
             self.current_frame = frame_number
+            # Store in cache, evict least recently used if cache is full
+            if len(self.frame_cache) >= self.cache_size:
+                self.frame_cache.popitem(last=False)
+            self.frame_cache[frame_number] = frame
+            self.frame_cache.move_to_end(frame_number)
             return frame
         else:
             raise ValueError(f"Failed to read frame {frame_number}")