From e0b3008c3156c6dd9fd69449be9f215d71a00af9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Eren=20G=C3=B6lge?= <egolge@coqui.ai>
Date: Mon, 5 Apr 2021 00:01:38 +0200
Subject: [PATCH] allow choosing the log function used for amptodb conversion

---
 TTS/utils/audio.py | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/TTS/utils/audio.py b/TTS/utils/audio.py
index 9a50d908..a4b6ef0a 100644
--- a/TTS/utils/audio.py
+++ b/TTS/utils/audio.py
@@ -47,6 +47,7 @@ class AudioProcessor(object):
                  sample_rate=None,
                  resample=False,
                  num_mels=None,
+                 log_func='np.log10',
                  min_level_db=None,
                  frame_shift_ms=None,
                  frame_length_ms=None,
@@ -96,6 +97,15 @@ class AudioProcessor(object):
         self.trim_db = trim_db
         self.do_sound_norm = do_sound_norm
         self.stats_path = stats_path
+        # setup exp_func for db to amp conversion
+        print(f'self.log_func = {log_func}')
+        exec(f'self.log_func = {log_func}')  #pylint: disable=exec-used
+        if self.log_func.__name__ == 'log':
+            self.exp_func = np.exp
+        elif self.log_func.__name__ == 'log10':
+            self.exp_func = lambda x: 10 ** x
+        else:
+            raise ValueError(' [!] unknown `log_func` value.')
         # setup stft parameters
         if hop_length is None:
             # compute stft parameters from given time values
@@ -227,11 +237,12 @@ class AudioProcessor(object):
     ### DB and AMP conversion ###
     # pylint: disable=no-self-use
     def _amp_to_db(self, x):
-        return self.spec_gain * np.log10(np.maximum(1e-5, x))
+        return self.spec_gain * self.log_func(np.maximum(1e-5, x))
 
     # pylint: disable=no-self-use
     def _db_to_amp(self, x):
-        return np.power(10.0, x / self.spec_gain)
+        return self.exp_func(x / self.spec_gain)
+
 
     ### Preemphasis ###
     def apply_preemphasis(self, x):