Fix two bugs for blank voice (empty speech): (#1403)

jianganghan

2024-02-29 f272eb4ef78e12a1ef4ae451b114f980a2682d51

1
{"unk_token": "<|endoftext|>", "bos_token": "<|endoftext|>", "eos_token": "<|endoftext|>", "add_prefix_space": false, "model_max_length": 1024, "special_tokens_map_file": null, "name_or_path": "gpt2", "tokenizer_class": "GPT2Tokenizer"}