small fixes

model.py

@@ -200,6 +200,11 @@ def _get_librispeech_pre_trained_model(
     )
     tokens = _get_token_filename(repo_id=repo_id, subfolder="data/lang_bpe_500")
 
+    feat_config = sherpa.FeatureConfig()
+    feat_config.fbank_opts.frame_opts.samp_freq = sample_rate
+    feat_config.fbank_opts.mel_opts.num_bins = 80
+    feat_config.fbank_opts.frame_opts.dither = 0
+
     config = sherpa.OfflineRecognizerConfig(
         nn_model=nn_model,
         tokens=tokens,