Create cmvn_converter.py

egs/aishell/transformer/utils/cmvn_converter.py

@@ -0,0 +1,53 @@
+import argparse
+import json
+import numpy as np
+
+
+def get_parser():
+    parser = argparse.ArgumentParser(
+        description="cmvn converter",
+        formatter_class=argparse.ArgumentDefaultsHelpFormatter,
+    )
+    parser.add_argument(
+        "--cmvn-json",
+        "-c",
+        default=False,
+        required=True,
+        type=str,
+        help="cmvn json file",
+    )
+    parser.add_argument(
+        "--am-mvn",
+        "-a",
+        default=False,
+        required=True,
+        type=str,
+        help="am mvn file",
+    )
+    return parser
+
+def main():
+    parser = get_parser()
+    args = parser.parse_args()
+
+    with open(args.cmvn_json, "r") as fin:
+        cmvn_dict = json.load(fin)
+
+    mean_stats = np.array(cmvn_dict["mean_stats"])
+    var_stats = np.array(cmvn_dict["var_stats"])
+    total_frame = np.array(cmvn_dict["total_frames"])
+
+    mean = -1.0 * mean_stats / total_frame
+    var = 1.0 / np.sqrt(var_stats / total_frame - mean * mean)
+    dims = mean.shape[0]
+    with open(args.am_mvn, 'w') as fout:
+        fout.write("<Nnet>" + "\n" + "<Splice> " + str(dims) + " " + str(dims) + '\n' + "[ 0 ]" + "\n" + "<AddShift> " + str(dims) + " " + str(dims) + "\n")
+        mean_str = str(list(mean)).replace(',', '').replace('[', '[ ').replace(']', ' ]')
+        fout.write("<LearnRateCoef> 0 " + mean_str + '\n')
+        fout.write("<Rescale> " + str(dims) + " " + str(dims) + '\n')
+        var_str = str(list(var)).replace(',', '').replace('[', '[ ').replace(']', ' ]')
+        fout.write("<LearnRateCoef> 0 " + var_str + '\n')
+        fout.write("</Nnet>" + '\n')
+
+if __name__ == '__main__':
+    main()