APM QA refactoring: render stream support, echo path simulation, new export engine

webrtc/modules/audio_processing/test/py_quality_assessment/quality_assessment/echo_path_simulation.py

Index: webrtc/modules/audio_processing/test/py_quality_assessment/quality_assessment/echo_path_simulation.py
diff --git a/webrtc/modules/audio_processing/test/py_quality_assessment/quality_assessment/echo_path_simulation.py b/webrtc/modules/audio_processing/test/py_quality_assessment/quality_assessment/echo_path_simulation.py
new file mode 100644
index 0000000000000000000000000000000000000000..730facb799c9820d0c006116dc6483c3fbb1158a
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+++ b/webrtc/modules/audio_processing/test/py_quality_assessment/quality_assessment/echo_path_simulation.py
@@ -0,0 +1,101 @@
+# Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+#
+# Use of this source code is governed by a BSD-style license
+# that can be found in the LICENSE file in the root of the source
+# tree. An additional intellectual property rights grant can be found
+# in the file PATENTS.  All contributing project authors may
+# be found in the AUTHORS file in the root of the source tree.
+
+"""Echo path simulation module.
+"""
+
+import logging
+
+
+class EchoPathSimulator(object):
+  """Abstract class for the echo path simulators.
+
+  In general, an echo path simulator mixes the capture and the render signals

[peah-webrtc, 2017/05/03 08:10:08]

I would not characterize an echo path simulator as that. I think an echo path
simulator only simulates the echo path and I would not expect any mixing of the
capture signal to be part of the echo path simulation. Is it possible to
reformulate this accordingly? Or should we rather change the name of the class?

[AleBzk, 2017/05/15 08:22:57]

Thanks a lot for this comment.
I mixed two responsibilities in this class.
As we discussed offline, I decoupled them adding ApmInputMixer.

+  simulating what a microphone records due to the presence of echo paths (e.g.,
+  mechanical or electrical path).
+  """
+
+  NAME = None
+  REGISTERED_CLASSES = {}
+
+  def __init__(self):
+    pass
+
+  def Simulate(self, output_path):
+    """Simulates echo path (abstract method).
+
+    Args:
+      output_path: Path in which any output can be saved.
+
+    Returns:
+      Path to the generated audio track file.
+    """
+    # TODO(alessiob): Remove once ctor implemented.
+    raise NotImplementedError()
+
+  @classmethod
+  def RegisterClass(cls, class_to_register):
+    """Registers an EchoPathSimulator implementation.
+
+    Decorator to automatically register the classes that extend
+    EchoPathSimulator.
+    Example usage:
+
+    @EchoPathSimulator.RegisterClass
+    class LinearEchoPathSimulator(EchoPathSimulator):
+      pass
+    """
+    cls.REGISTERED_CLASSES[class_to_register.NAME] = class_to_register
+    return class_to_register
+
+
+@EchoPathSimulator.RegisterClass
+class LinearEchoPathSimulator(EchoPathSimulator):
+  """Simulates linear echo path.
+
+  It applies a given impulse response to the render input and then it sums the

[peah-webrtc, 2017/05/03 08:10:08]

This is not clear to me: then it sums the signal to the capture input signal.

[peah-webrtc, 2017/05/03 08:10:08]

Please replace "It" with something else, as it is a bit ambiguous. Suggestions:
It applies -> Applies
It applies  -> This class applies
It applies -> This simulator applies

[AleBzk, 2017/05/15 08:22:57]

Doesn't apply anymore.

+  signal to the capture input signal.
+  """
+
+  NAME = 'linear'
+
+  def __init__(self, capture_input_filepath, render_input_filepath,
+               impulse_response):
+    EchoPathSimulator.__init__(self)
+    # TODO(alessiob): Remove once ctor implemented.
+    logging.debug(capture_input_filepath)
+    logging.debug(render_input_filepath)
+    logging.debug(impulse_response)
+
+  def Simulate(self, output_path):
+    """Simulates linear echo path."""
+    # TODO(alessiob): Implement.
+    pass
+
+
+# TODO(alessiob): Remove comment when class implemented.
+# @EchoPathSimulator.RegisterClass

[peah-webrtc, 2017/05/03 08:10:08]

What makes RecordedEchoPathSimulator from LinearEchoPathSimulator? The latter is
registered, but not the former. And neither of them yet contain the simulation
code. it would make sense to treat those similarly in terms of
@EchoPathSimulator.RegisterClass

[AleBzk, 2017/05/15 08:22:57]

Fixed. I also added the implementation and a "no echo" simulator.

+class RecordedEchoPathSimulator(EchoPathSimulator):
+  """Uses recorded echo.
+
+  It uses the clean capture input file name to build the file name of the

[peah-webrtc, 2017/05/03 08:10:08]

This is an echopath simulator, and I think it would be better if the comment
mentioned more about how the simulation is done. As it is now, it mentions the
construction of file names which is a bit misleading I think.

[AleBzk, 2017/05/15 08:22:57]

Well, I could describe the setup to record echo.
But I don't think this class is the right place for doing that.
Let's discuss this point offline.

+  corresponding recording containing capture input and echo. Such file is

[peah-webrtc, 2017/05/03 08:10:08]

Such a file

[AleBzk, 2017/05/15 08:22:57]

Done.

+  expected to be already existing.
+  """
+
+  NAME = 'recorded'
+
+  def __init__(self, capture_input_filepath):
+    EchoPathSimulator.__init__(self)
+    # TODO(alessiob): Remove once ctor implemented.
+    logging.debug(capture_input_filepath)
+
+  def Simulate(self, output_path):
+    """Uses recorded echo path."""
+    # TODO(alessiob): Implement.
+    pass