copy-feats ark:train.ark   ark,t:/train.txt           ark转化为txt

 copy-feats ark,t:train.txt  ark:train.ark              txt转化为ark

copu-feats ark:mfcc.ark ark,scp:feat.ark,feat.scp 生成scp文件

nnet3-copy-egs 查看egs.1.ark