Add memory optimization: low quality rendering + automatic cleanup

backend/runner.py

@@ -1,40 +1,103 @@
 import os
 import subprocess
 import uuid
+import shutil
+import glob
+from pathlib import Path
 
 # Get the directory of the current script (backend/)
 BASE_DIR = os.path.dirname(os.path.abspath(__file__))
 MEDIA_DIR = os.path.join(BASE_DIR, "media")
 
+def cleanup_old_files():
+    """Clean up old scene files and media to free memory"""
+    try:
+        # Remove old scene files (keep only last 2)
+        scene_files = sorted(glob.glob(os.path.join(BASE_DIR, "scene_*.py")), key=os.path.getmtime)
+        for old_file in scene_files[:-2]:
+            try:
+                os.remove(old_file)
+                print(f"🗑️ Cleaned up old scene file: {old_file}")
+            except Exception as e:
+                print(f"⚠️ Could not remove {old_file}: {e}")
+        
+        # Remove old video folders (keep only last 3)
+        videos_dir = os.path.join(MEDIA_DIR, "videos")
+        if os.path.exists(videos_dir):
+            video_folders = sorted(
+                [f for f in Path(videos_dir).iterdir() if f.is_dir()],
+                key=os.path.getmtime
+            )
+            for old_folder in video_folders[:-3]:
+                try:
+                    shutil.rmtree(old_folder)
+                    print(f"🗑️ Cleaned up old video folder: {old_folder}")
+                except Exception as e:
+                    print(f"⚠️ Could not remove {old_folder}: {e}")
+        
+        # Remove old audio files (keep only last 5)
+        audio_files = sorted(glob.glob(os.path.join(BASE_DIR, "step_*_narration.mp3")), key=os.path.getmtime)
+        for old_audio in audio_files[:-5]:
+            try:
+                os.remove(old_audio)
+                print(f"🗑️ Cleaned up old audio file: {old_audio}")
+            except Exception as e:
+                print(f"⚠️ Could not remove {old_audio}: {e}")
+                
+    except Exception as e:
+        print(f"⚠️ Cleanup error: {e}")
+
 async def render_scene(code: str):
+    # Clean up old files before rendering
+    cleanup_old_files()
+    
     # Create a unique ID for this run
     run_id = str(uuid.uuid4())
     filename = f"scene_{run_id}.py"
     
     # Save code to file in the backend directory
     filepath = os.path.join(BASE_DIR, filename)
-    with open(filepath, "w") as f:
+    with open(filepath, "w", encoding='utf-8') as f:
         f.write(code)
         
-    # Run Manim
-    # manim -qm --media_dir MEDIA_DIR filename.py GenScene
+    # Run Manim with LOW quality (-ql) for better memory usage
+    # -ql = 480p15, much lighter than -qm (720p30)
     
-    cmd = ["manim", "-qm", "--media_dir", MEDIA_DIR, filepath, "GenScene"]
+    cmd = ["manim", "-ql", "--media_dir", MEDIA_DIR, filepath, "GenScene"]
     
     try:
         result = subprocess.run(cmd, capture_output=True, text=True, check=True)
-        print("Manim Output:", result.stdout)
+        print("✓ Manim render completed")
     except subprocess.CalledProcessError as e:
-        print("Manim Error:", e.stderr)
+        print("❌ Manim Error:", e.stderr)
+        # Clean up failed scene file
+        try:
+            os.remove(filepath)
+        except:
+            pass
         raise Exception(f"Manim failed: {e.stderr}")
         
     # Construct expected output path
-    # Manim structure with --media_dir: {MEDIA_DIR}/videos/{filename_without_extension}/720p30/GenScene.mp4
+    # Low quality: {MEDIA_DIR}/videos/{filename_without_extension}/480p15/GenScene.mp4
     
     video_folder = filename.replace(".py", "")
-    video_path = os.path.join(MEDIA_DIR, "videos", video_folder, "720p30", "GenScene.mp4")
+    video_path = os.path.join(MEDIA_DIR, "videos", video_folder, "480p15", "GenScene.mp4")
     
     if not os.path.exists(video_path):
+        # Clean up scene file
+        try:
+            os.remove(filepath)
+        except:
+            pass
         raise Exception(f"Video file not found at {video_path}")
+    
+    print(f"✓ Video created: {video_path}")
+    
+    # Clean up the scene file immediately after successful render
+    try:
+        os.remove(filepath)
+        print(f"🗑️ Cleaned up scene file: {filepath}")
+    except Exception as e:
+        print(f"⚠️ Could not remove scene file: {e}")
         
     return video_path