refactor(main.py): simplify memory usage calculation and streamline video safety checks

main.py

@@ -7,6 +7,8 @@ import argparse
 import shutil
 import time
 import threading
+import subprocess
+import json
 from concurrent.futures import ThreadPoolExecutor
 from pathlib import Path
 from typing import List
@@ -58,6 +60,7 @@ class MediaGrader:
         self.segment_caps = []
         self.segment_frames = []
         self.segment_positions = []
+        self.segment_end_positions = []  # Track where each segment should loop back to
         
         self.timeline_visible = True
         
@@ -486,34 +489,27 @@ class MediaGrader:
         if not self.is_video(self.media_files[self.current_index]):
             return
             
-        # Safety check for huge videos
-        safe_frame_count = max(1, int(self.total_frames * 0.6))
         
         # Calculate actual memory usage based on frame dimensions
         frame_width = int(self.current_cap.get(cv2.CAP_PROP_FRAME_WIDTH))
         frame_height = int(self.current_cap.get(cv2.CAP_PROP_FRAME_HEIGHT))
-        bytes_per_frame = frame_width * frame_height * 3  # RGB (3 bytes per pixel)
-        total_bytes = safe_frame_count * bytes_per_frame
-        total_mb = total_bytes / (1024 * 1024)
-        total_gb = total_mb / 1024
-        
+        total_mb = frame_width * frame_height * 3 / (1024 * 1024)
         # Memory-based limits (not frame count)
-        if total_gb > 8:  # 8GB limit
+        if total_mb > 8000:  # 8GB limit
             print(f"Video too large for preloading!")
             print(f"  Resolution: {frame_width}x{frame_height}")
-            print(f"  Frames: {safe_frame_count} frames would use {total_gb:.1f}GB RAM")
+            print(f"  Frames: {self.total_frames} frames would use {total_mb:.1f}GB RAM")
             print(f"Multi-segment mode not available for videos requiring >8GB RAM")
             return
         elif total_mb > 500:  # 500MB warning
             print(f"Large video detected:")
             print(f"  Resolution: {frame_width}x{frame_height}")
-            print(f"  Memory: {safe_frame_count} frames will use {total_mb:.0f}MB RAM")
+            print(f"  Memory: {self.total_frames} frames will use {total_mb:.0f}GB RAM")
             print("Press any key to continue or 'q' to cancel...")
             # Note: In a real implementation, you'd want proper input handling here
             
         start_time = time.time()
         print(f"Setting up {self.segment_count} segments with video preloading...")
-        print(f"Will preload {safe_frame_count} frames ({frame_width}x{frame_height}) = {total_mb:.0f}MB RAM")
         
         try:
             print("Cleaning up existing captures...")
@@ -527,6 +523,7 @@ class MediaGrader:
             self.segment_caps = [None] * self.segment_count  # Keep for compatibility
             self.segment_frames = [None] * self.segment_count
             self.segment_positions = []
+            self.segment_end_positions = []
             self.segment_current_frames = [0] * self.segment_count  # Track current frame for each segment
             
             # Calculate target positions
@@ -538,13 +535,23 @@ class MediaGrader:
             for i in range(self.segment_count):
                 if self.segment_count <= 1:
                     position_ratio = 0
+                    end_ratio = 1.0
                 else:
                     position_ratio = i / (self.segment_count - 1)
-                start_frame = int(position_ratio * (safe_frame_count - 1))
-                start_frame = max(0, min(start_frame, safe_frame_count - 1))
+                    end_ratio = (i + 1) / (self.segment_count - 1) if i < self.segment_count - 1 else 1.0
+                
+                start_frame = int(position_ratio * (self.total_frames - 1))
+                end_frame = int(end_ratio * (self.total_frames - 1))
+                
+                start_frame = max(0, min(start_frame, self.total_frames - 1))
+                end_frame = max(start_frame + 1, min(end_frame, self.total_frames - 1))  # Ensure at least 1 frame per segment
+                
                 self.segment_positions.append(start_frame)
+                self.segment_end_positions.append(end_frame)
                 self.segment_current_frames[i] = start_frame  # Start each segment at its position
+                
             print(f"Segment positions: {self.segment_positions}")
+            print(f"Segment end positions: {self.segment_end_positions}")
             
             # Preload the entire video into memory - simple and fast
             print("Preloading entire video into memory...")
@@ -557,7 +564,7 @@ class MediaGrader:
                 frames = []
                 frame_count = 0
                 
-                while frame_count < safe_frame_count:
+                while frame_count < self.total_frames:
                     ret, frame = self.current_cap.read()
                     if ret and frame is not None:
                         frames.append(frame)
@@ -600,25 +607,35 @@ class MediaGrader:
         self.segment_caps = []
         self.segment_frames = []
         self.segment_positions = []
+        self.segment_end_positions = []
         if hasattr(self, 'video_frame_cache'):
             self.video_frame_cache = []
         if hasattr(self, 'segment_current_frames'):
             self.segment_current_frames = []
 
     def update_segment_frames(self):
-        """Update frames for segments using the preloaded video array - smooth playback!"""
+        """Update frames for segments - each segment loops within its own range"""
         if not self.multi_segment_mode or not self.segment_frames or not hasattr(self, 'video_frame_cache'):
             return
         
         for i in range(len(self.segment_frames)):
             if self.segment_frames[i] is not None and self.video_frame_cache:
+                # Advance to next frame in this segment
                 self.segment_current_frames[i] += 1
                 
-                if self.segment_current_frames[i] >= len(self.video_frame_cache):
-                    self.segment_current_frames[i] = 0
+                # Get the segment boundaries
+                start_frame = self.segment_positions[i]
+                end_frame = self.segment_end_positions[i]
                 
-                # Direct reference - no copy needed for display
-                self.segment_frames[i] = self.video_frame_cache[self.segment_current_frames[i]]
+                # Loop within the segment bounds
+                if self.segment_current_frames[i] > end_frame:
+                    # Loop back to start of segment
+                    self.segment_current_frames[i] = start_frame
+                
+                # Ensure we don't go beyond the video cache
+                if self.segment_current_frames[i] < len(self.video_frame_cache):
+                    # 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"""