[demo] support English

app.py

@@ -19,8 +19,8 @@ import wenetruntime as wenet
 import librosa
 
 wenet.set_log_level(2)
-decoder_cn = wenet.Decoder(lang='chs')
-decoder_en = wenet.Decoder(lang='en')
+# decoder_cn = wenet.Decoder(lang='chs')
+# decoder_en = wenet.Decoder(lang='en')
 
 
 def recognition(audio, lang='CN'):
@@ -30,8 +30,10 @@ def recognition(audio, lang='CN'):
     # NOTE: model supports 16k sample_rate
     y = (y * (1 << 15)).astype("int16")
     if lang == 'CN':
+        decoder_cn = wenet.Decoder(lang='chs')
         ans = decoder_cn.decode(y.tobytes(), True)
     elif lang == 'EN':
+        decoder_en = wenet.Decoder(lang='en')
         ans = decoder_en.decode(y.tobytes(), True)
     else:
         return "ERROR! Please select a language!"