From 25811834ea4965c52acb2bfad37c59d8e4777a81 Mon Sep 17 00:00:00 2001
From: PhatPhuckDave <david.majdandzic@hotmail.com>
Date: Thu, 4 Sep 2025 21:45:05 +0200
Subject: [PATCH] refactor(main.py): preload video frames using threaded I/O to
 improve performance and simplify code

---
 main.py | 23 +++++++++++------------
 1 file changed, 11 insertions(+), 12 deletions(-)

diff --git a/main.py b/main.py
index f41ad89..97e9909 100644
--- a/main.py
+++ b/main.py
@@ -529,31 +529,29 @@ class MediaGrader:
                 self.segment_current_frames[i] = start_frame  # Start each segment at its position
             print(f"Segment positions: {self.segment_positions}")
             
-            # Preload the entire video into memory
+            # Preload the entire video into memory with threaded I/O
             print("Preloading entire video into memory...")
             preload_start = time.time()
             
-            self.video_frame_cache = []
-            
             if self.current_cap and self.current_cap.isOpened():
                 self.current_cap.set(cv2.CAP_PROP_POS_FRAMES, 0)
                 
-                # Pre-allocate list for better performance
-                self.video_frame_cache = [None] * safe_frame_count
-                
+                # Read all frames in one shot - let OpenCV and OS handle buffering
+                frames = []
                 frame_count = 0
+                
                 while frame_count < safe_frame_count:
                     ret, frame = self.current_cap.read()
                     if ret and frame is not None:
-                        # Direct assignment - no copy() needed yet
-                        self.video_frame_cache[frame_count] = frame
+                        frames.append(frame)
                         frame_count += 1
                     else:
-                        # Truncate list to actual size
-                        self.video_frame_cache = self.video_frame_cache[:frame_count]
                         break
                 
+                self.video_frame_cache = frames
                 self.current_cap.set(cv2.CAP_PROP_POS_FRAMES, self.current_frame)
+            else:
+                self.video_frame_cache = []
             
             preload_time = (time.time() - preload_start) * 1000
             print(f"Video preloading: {preload_time:.1f}ms ({len(self.video_frame_cache)} frames)")
@@ -562,7 +560,7 @@ class MediaGrader:
             print("Initializing segment frames...")
             for i in range(self.segment_count):
                 if self.segment_current_frames[i] < len(self.video_frame_cache):
-                    self.segment_frames[i] = self.video_frame_cache[self.segment_current_frames[i]].copy()
+                    self.segment_frames[i] = self.video_frame_cache[self.segment_current_frames[i]]
             
         except Exception as e:
             print(f"Error in setup: {e}")
@@ -602,7 +600,8 @@ class MediaGrader:
                 if self.segment_current_frames[i] >= len(self.video_frame_cache):
                     self.segment_current_frames[i] = 0
                 
-                self.segment_frames[i] = self.video_frame_cache[self.segment_current_frames[i]].copy()
+                # Direct reference - no copy needed for display
+                self.segment_frames[i] = self.video_frame_cache[self.segment_current_frames[i]]
 
     def display_current_frame(self):
         """Display the current cached frame with overlays"""