add stderr

hls_download.py

@@ -37,6 +37,7 @@ def download_clips(stream_url, out_dir, start_time, end_time, resize=True, use_6
         except subprocess.CalledProcessError as e:
             print(f"Error occurred: {e}")
             print(f"ffmpeg output: {e.output}")
+            print(f"ffmpeg stderr: {e.stderr}")
             return output_file
     # else:
     #     os.rename(tmp_file, output_file)