Avoid multiple checkpoint restauration and add a specific tf graph for each Separator which makes it possible to instanciate several ones

spleeter/separator.py

@@ -60,14 +60,20 @@ class Separator(object):
         self._params = load_configuration(params_descriptor)
         self._sample_rate = self._params['sample_rate']
         self._MWF = MWF
+        self._tf_graph = tf.Graph()
         self._predictor = None
         self._input_provider = None
         self._builder = None
         self._features = None
+        self._session = None
         self._pool = Pool() if multiprocess else None
         self._tasks = []
         self._params["stft_backend"] = get_backend(stft_backend)
 
+    def __del__(self):
+        if self._session:
+            self._session.close()
+
     def _get_predictor(self):
         """ Lazy loading access method for internal predictor instance.
 
@@ -147,30 +153,35 @@ class Separator(object):
             self._builder = EstimatorSpecBuilder(self._get_features(), self._params)
         return self._builder
 
+    def _get_session(self):
+        if self._session is None:
+            saver = tf.train.Saver()
+            latest_checkpoint = tf.train.latest_checkpoint(get_default_model_dir(self._params['model_dir']))
+            self._session = tf.Session()
+            saver.restore(self._session, latest_checkpoint)
+        return self._session
+
     def _separate_librosa(self, waveform, audio_id):
         """
         Performs separation with librosa backend for STFT.
         """
-        out = {}
-        features = self._get_features()
+        with self._tf_graph.as_default():
+            out = {}
+            features = self._get_features()
 
-        latest_checkpoint = tf.train.latest_checkpoint(get_default_model_dir(self._params['model_dir']))
+            # TODO: fix the logic, build sometimes return, sometimes set attribute
+            outputs = self._get_builder().outputs
+            stft = self._stft(waveform)
+            if stft.shape[-1] == 1:
+                stft = np.concatenate([stft, stft], axis=-1)
+            elif stft.shape[-1] > 2:
+                stft = stft[:, :2]
 
-        # TODO: fix the logic, build sometimes return, sometimes set attribute
-        outputs = self._get_builder().outputs
-        stft = self._stft(waveform)
-        if stft.shape[-1] == 1:
-            stft = np.concatenate([stft, stft], axis=-1)
-        elif stft.shape[-1] > 2:
-            stft = stft[:, :2]
-
-        saver = tf.train.Saver()
-        with tf.Session() as sess:
-            saver.restore(sess, latest_checkpoint)
+            sess = self._get_session()
             outputs = sess.run(outputs, feed_dict=self._get_input_provider().get_feed_dict(features, stft, audio_id))
             for inst in self._get_builder().instruments:
                 out[inst] = self._stft(outputs[inst], inverse=True, length=waveform.shape[0])
-        return out
+            return out
 
     def separate(self, waveform, audio_descriptor=""):
         """ Performs separation on a waveform.