fix!: resolve problem of m4a

app.py

@@ -10,6 +10,7 @@ import logging
 from inference import proc_folder_direct
 from pathlib import Path
 import spaces
+from pydub.exceptions import CouldntEncodeError
 
 OUTPUT_FOLDER = "separation_results/"
 INPUT_FOLDER = "input"
@@ -119,10 +120,18 @@ def combine_stems_for_all(input_dir, output_format):
         # Trim silence from the end of the combined audio
         trimmed_combined = trim_silence_at_end(combined)
 
-        # Determine the output file format
+        # Determine the output file format and codec
         output_file = os.path.join(subdir, f"{song_name}.{output_format}")
-        trimmed_combined.export(output_file, format=output_format)
-        print(f"Exported combined stems to {output_file}")
+
+        try:
+            if output_format == "m4a":
+                trimmed_combined.export(output_file, format="ipod", codec="aac")
+            else:
+                trimmed_combined.export(output_file, format=output_format)
+            print(f"Exported combined stems to {output_file}")
+        except CouldntEncodeError as e:
+            print(f"Encoding failed: {e}")
+            raise
 
         return output_file