Kaldi PLDA reading method

kaldi_io.py

+# -*- coding: utf-8 -*-
+#
+# This file is part of SIDEKIT.
+#
+# SIDEKIT is a python package for speaker verification.
+# Home page: http://www-lium.univ-lemans.fr/sidekit/
+#
+# SIDEKIT is a python package for speaker verification.
+# Home page: http://www-lium.univ-lemans.fr/sidekit/
+#
+# SIDEKIT is free software: you can redistribute it and/or modify
+# it under the terms of the GNU LLesser General Public License as
+# published by the Free Software Foundation, either version 3 of the License,
+# or (at your option) any later version.
+#
+# SIDEKIT is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with SIDEKIT.  If not, see <http://www.gnu.org/licenses/>.
+
+"""
+Copyright 2014-2019 Anthony Larcher
+
+:mod:`kaldi_io` provides utilities to import Kaldi PLDA/LDA binaries.
+"""
+
+__author__ = "Gaël Le Lan"
+__email__ = "gael.lelan@orange.com"
+
+import sys
+
+import numpy as np
+
+BYTES_PER_DOUBLE = 8
+BYTES_PER_FLOAT = 4
+
+def read_plda(plda_file):
+    """
+    Import PLDA from Kaldi format
+    output PLDA parameters
+    :param plda_file: Kaldi format PLDA file
+    """
+    with open(plda_file, 'rb') as ins:
+        ins.read(2)
+        assert ins.read(7) == b'<Plda> '
+        fv_dv_value = ins.read(2)
+        assert ins.read(1) == b' '
+        next_bytes_to_read = ins.read(1)[0]
+        vec_dim = int.from_bytes(ins.read(next_bytes_to_read), byteorder='little')
+        if fv_dv_value == b'DV':
+            mean = np.fromstring(ins.read(vec_dim*BYTES_PER_DOUBLE), np.float64)
+        elif fv_dv_value == b'FV':
+            mean = np.fromstring(ins.read(vec_dim*BYTES_PER_FLOAT), np.float64)
+        else:
+            sys.exit('error reading mean')
+        fm_dm_value = ins.read(2)
+        assert ins.read(1) == b' '
+        next_bytes_to_read = ins.read(1)[0]
+        n_rows = int.from_bytes(ins.read(next_bytes_to_read), byteorder='little')
+        next_bytes_to_read = ins.read(1)[0]
+        n_cols = int.from_bytes(ins.read(next_bytes_to_read), byteorder='little')
+        if fm_dm_value == b'DM':
+            transform = np.fromstring(ins.read(n_rows*n_cols*BYTES_PER_DOUBLE),
+                                      np.float64).reshape(n_rows, n_cols)
+        elif fm_dm_value == b'FM':
+            transform = np.fromstring(ins.read(n_rows*n_cols*BYTES_PER_FLOAT),
+                                      np.float64).reshape(n_rows, n_cols)
+        else:
+            sys.exit('error reading transform')
+        fv_dv_value = ins.read(2)
+        assert ins.read(1) == b' '
+        next_bytes_to_read = ins.read(1)[0]
+        vec_dim = int.from_bytes(ins.read(next_bytes_to_read), byteorder='little')
+        if fv_dv_value == b'DV':
+            psi = np.fromstring(ins.read(vec_dim*BYTES_PER_DOUBLE), np.float64)
+        elif fv_dv_value == b'FV':
+            psi = np.fromstring(ins.read(vec_dim*BYTES_PER_FLOAT), np.float64)
+        else:
+            sys.exit('error reading Psi')
+        assert ins.readline() == b'</Plda> '
+    return mean, transform, psi