fix demo service && copy license for cv/language_guided_video_summarization

Link: https://code.alibaba-inc.com/Ali-MaaS/MaaS-lib/codereview/10985657

    * fix demo service && copy license

modelscope/msdatasets/task_datasets/language_guided_video_summarization_dataset.py

@@ -2,6 +2,21 @@
 # publicly available at https://github.com/e-apostolidis/PGL-SUM, follow the
 # license https://github.com/e-apostolidis/PGL-SUM/blob/master/LICENSE.md.
 
+# Copyright (c) 2021, Evlampios Apostolidis, Georgios Balaouras, Vasileios Mezaris,
+# Ioannis Patras / CERTH-ITI. All rights reserved. This code is provided for academic,
+# non-commercial use only. Redistribution and use in source and binary forms, with or without modification,
+# are permitted for academic non-commercial use provided that the following conditions are met:
+
+# Redistributions of source code must retain the above copyright notice, this list of conditions and the following
+# disclaimer. Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the
+# following disclaimer in the documentation provided with the distribution.
+# This software is provided by the authors "as is" and any express or implied warranties, including, but not limited to,
+# the implied warranties of merchantability and fitness for a particular purpose are disclaimed. In no event shall the
+# authors be liable for any direct, indirect, incidental, special, exemplary, or consequential damages (including, but
+# not limited to, procurement of substitute goods or services; loss of use, data, or profits; or business interruption)
+# however caused and on any theory of liability, whether in contract, strict liability, or tort (including negligence or
+# otherwise) arising in any way out of the use of this software, even if advised of the possibility of such damage.
+
 import os
 
 import h5py

modelscope/pipelines/cv/language_guided_video_summarization_pipeline.py

@@ -91,7 +91,7 @@ class LanguageGuidedVideoSummarizationPipeline(Pipeline):
             frame_idx += 1
         n_frame = frame_idx
 
-        if sentences is None:
+        if sentences is None or len(sentences) == 0:
             logger.info('input sentences is none, using sentences from video!')
 
             tmp_path = os.path.join(self.tmp_dir, 'tmp')