Update app.py

app.py

@@ -464,6 +464,7 @@ def wrap_text_for_ass(text: str, max_width: int, font_family: str, font_size: in
     
     return "\\N".join(lines)
 
+
 def create_caption_ass(captions: List[CaptionSegment], style: CaptionStyle, work_dir: str, font_path: str) -> str:
     """Create ASS subtitle file for captions with enhanced colors"""
     
@@ -487,7 +488,7 @@ def create_caption_ass(captions: List[CaptionSegment], style: CaptionStyle, work
     bg_color_rgb = COLOR_MAP.get(bg_color_name, "000000")
     # Convert RGB to BGR for background
     bg_color_bgr = bg_color_rgb[4:6] + bg_color_rgb[2:4] + bg_color_rgb[0:2]
-    # FIX: Alpha should be (1 - opacity) * 255, where alpha=0 is fully opaque
+    # Alpha: 0 = opaque, 255 = transparent
     bg_alpha = int((1 - bg_opacity) * 255)
     print(f"🎨 BG color: {bg_color_name} -> RGB={bg_color_rgb} -> BGR={bg_color_bgr}, Opacity={bg_opacity}, Alpha={bg_alpha}")
     
@@ -549,8 +550,11 @@ Format: Layer, Start, End, Style, Name, MarginL, MarginR, MarginV, Effect, Text
     
     print(f"📝 Created caption ASS file with {len(captions)} captions")
     print(f"📝 Style line: BorderStyle=3, Outline={style.padding}, BackColor=&H{bg_alpha:02X}{bg_color_bgr}")
+    
+    # For captions, we need to use the ASS method (can't use drawtext for multiple timed captions)
+    # But we've improved the ASS formatting for better background rendering
     return ass_file
-
+    
 # =============================================
 # SRT PARSING FUNCTIONS
 # =============================================