From c7c092d3f303838d62e24bf8b54c3c1f83529019 Mon Sep 17 00:00:00 2001
From: PhatPhuckDave <david.majdandzic@hotmail.com>
Date: Tue, 16 Sep 2025 13:29:09 +0200
Subject: [PATCH] Implement frame caching in VideoEditor: add methods for
 managing frame cache with LRU eviction, improving playback performance by
 reducing frame retrieval time. Clear cache when switching videos to optimize
 memory usage.

---
 croppa/main.py | 65 ++++++++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 60 insertions(+), 5 deletions(-)

diff --git a/croppa/main.py b/croppa/main.py
index c83abb5..4fa3222 100644
--- a/croppa/main.py
+++ b/croppa/main.py
@@ -12,7 +12,6 @@ import threading
 import queue
 import subprocess
 import ctypes
-from ctypes import wintypes
 
 def get_active_window_title():
     """Get the title of the currently active window"""
@@ -39,7 +38,6 @@ class ProjectView:
     THUMBNAIL_MARGIN = 20
     PROGRESS_BAR_HEIGHT = 8
     TEXT_HEIGHT = 30
-    ITEM_HEIGHT = THUMBNAIL_SIZE[1] + PROGRESS_BAR_HEIGHT + TEXT_HEIGHT + THUMBNAIL_MARGIN
     
     # Colors
     BG_COLOR = (40, 40, 40)
@@ -392,6 +390,9 @@ class VideoEditor:
 
     # Auto-repeat seeking configuration
     AUTO_REPEAT_DISPLAY_RATE = 1.0
+    
+    # Frame cache configuration
+    MAX_CACHE_FRAMES = 3000
 
     # Timeline configuration
     TIMELINE_HEIGHT = 60
@@ -519,6 +520,10 @@ class VideoEditor:
         self.cached_transformed_frame = None
         self.cached_frame_number = None
         self.cached_transform_hash = None
+        
+        # Frame cache for video playback
+        self.frame_cache = {}  # frame_number -> frame_data
+        self.cache_access_order = []  # Track access order for LRU eviction
 
         # Project view mode
         self.project_view_mode = False
@@ -772,6 +777,10 @@ class VideoEditor:
         if hasattr(self, "cap") and self.cap:
             self.cap.release()
 
+        # Clear frame cache when switching videos
+        self.frame_cache.clear()
+        self.cache_access_order.clear()
+
         self.video_path = media_path
         self.is_image_mode = self._is_image_file(media_path)
 
@@ -879,11 +888,19 @@ class VideoEditor:
             self.current_display_frame = self.static_image.copy()
             return True
         else:
-            # For videos, use OpenCV for reliable seeking
+            # Check cache first
+            cached_frame = self._get_frame_from_cache(self.current_frame)
+            if cached_frame is not None:
+                self.current_display_frame = cached_frame
+                return True
+            
+            # Not in cache, read from capture
             self.cap.set(cv2.CAP_PROP_POS_FRAMES, self.current_frame)
             ret, frame = self.cap.read()
             if ret:
                 self.current_display_frame = frame
+                # Add to cache
+                self._add_frame_to_cache(self.current_frame, frame)
                 return True
             return False
 
@@ -1102,6 +1119,36 @@ class VideoEditor:
         self.cached_frame_number = None
         self.cached_transform_hash = None
 
+    def _manage_frame_cache(self):
+        """Manage frame cache size using LRU eviction"""
+        while len(self.frame_cache) > self.MAX_CACHE_FRAMES:
+            # Remove least recently used frame
+            oldest_frame = self.cache_access_order.pop(0)
+            if oldest_frame in self.frame_cache:
+                del self.frame_cache[oldest_frame]
+
+    def _add_frame_to_cache(self, frame_number: int, frame_data):
+        """Add frame to cache with LRU management"""
+        self.frame_cache[frame_number] = frame_data.copy()
+        
+        # Update access order
+        if frame_number in self.cache_access_order:
+            self.cache_access_order.remove(frame_number)
+        self.cache_access_order.append(frame_number)
+        
+        # Manage cache size
+        self._manage_frame_cache()
+
+    def _get_frame_from_cache(self, frame_number: int):
+        """Get frame from cache and update access order"""
+        if frame_number in self.frame_cache:
+            # Update access order for LRU
+            if frame_number in self.cache_access_order:
+                self.cache_access_order.remove(frame_number)
+            self.cache_access_order.append(frame_number)
+            return self.frame_cache[frame_number].copy()
+        return None
+
     def apply_rotation(self, frame):
         """Apply rotation to frame"""
         if self.rotation_angle == 0:
@@ -2537,8 +2584,16 @@ class VideoEditor:
                 project_canvas = self.project_view.draw()
                 cv2.imshow("Project View", project_canvas)
 
-            # Key capture with NO DELAY - keys should be instant
-            key = cv2.waitKey(1) & 0xFF
+            # Calculate appropriate delay based on playback state
+            if self.is_playing and not self.is_image_mode:
+                # Use calculated frame delay for proper playback speed
+                delay_ms = self.calculate_frame_delay()
+            else:
+                # Use minimal delay when not playing for responsive UI
+                delay_ms = 1
+            
+            # Key capture with appropriate delay
+            key = cv2.waitKey(delay_ms) & 0xFF
 
             # Route keys based on window focus
             if key != 255:  # Key was pressed