Update main.py

main.py

@@ -99,9 +99,9 @@ async def create_slideshow(image_paths, audio_path, output_path, duration, zoom=
         filter_complex = ""
         for i in range(len(image_paths)):
             # Each input's video stream is processed with zoompan.
-            # The zoom increases by zoom_ratio per frame (starting at 1.0).
+            # The zoom increases by zoom_ratio per frame (starting at 1.0) and centers the image.
             filter_complex += (
-                f"[{i}:v]zoompan=z='if(eq(on,0),1,zoom+{zoom_ratio})':"
+                f"[{i}:v]zoompan=z='if(eq(on,0),1,zoom+{zoom_ratio})':x='iw/2-(iw/zoom)/2':y='ih/2-(ih/zoom)/2':"
                 f"d={duration*fps}:s=hd720, setpts=PTS-STARTPTS[v{i}];"
             )
         # Concatenate all processed video segments.
@@ -127,7 +127,7 @@ async def create_slideshow(image_paths, audio_path, output_path, duration, zoom=
             stdout=asyncio.subprocess.PIPE,
             stderr=asyncio.subprocess.PIPE
         )
-        stdout, stderr = await process.communicate()
+        _, stderr = await process.communicate()
         
         # Remove temporary concat file if it exists
         if not zoom and os.path.exists("temp_concat.txt"):