fix oov bug for sond inference (#555)

funasr/bin/diar_infer.py

@@ -235,8 +235,11 @@ class Speech2DiarizationSOND:
                 new_seq.append(x)
             else:
                 idx_list = np.where(seq < 2 ** vec_dim)[0]
-                idx = np.abs(idx_list - i).argmin()
-                new_seq.append(seq[idx_list[idx]])
+                if len(idx_list) > 0:
+                    idx = np.abs(idx_list - i).argmin()
+                    new_seq.append(seq[idx_list[idx]])
+                else:
+                    new_seq.append(0)
         return np.row_stack([int2vec(x, vec_dim) for x in new_seq])
 
     def post_processing(self, raw_logits: torch.Tensor, spk_num: int, output_format: str = "speaker_turn"):