Async audio processing API

API to injecting a heavy audio processing operation into WebRTC audio capture pipeline

Bug: webrtc:12003
Change-Id: I9f6f58f468bd84efd0a9d53d703db6229a03959e
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/165788
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Commit-Queue: Olga Sharonova <olka@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#32291}

modules/async_audio_processing/async_audio_processing.cc

@@ -0,0 +1,61 @@
+
+/*
+ *  Copyright (c) 2020 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.
+ */
+#include "modules/async_audio_processing/async_audio_processing.h"
+
+#include <utility>
+
+#include "api/audio/audio_frame.h"
+#include "api/task_queue/task_queue_factory.h"
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+AsyncAudioProcessing::Factory::~Factory() = default;
+AsyncAudioProcessing::Factory::Factory(AudioFrameProcessor& frame_processor,
+                                       TaskQueueFactory& task_queue_factory)
+    : frame_processor_(frame_processor),
+      task_queue_factory_(task_queue_factory) {}
+
+std::unique_ptr<AsyncAudioProcessing>
+AsyncAudioProcessing::Factory::CreateAsyncAudioProcessing(
+    AudioFrameProcessor::OnAudioFrameCallback on_frame_processed_callback) {
+  return std::make_unique<AsyncAudioProcessing>(
+      frame_processor_, task_queue_factory_,
+      std::move(on_frame_processed_callback));
+}
+
+AsyncAudioProcessing::~AsyncAudioProcessing() {
+  frame_processor_.SetSink(nullptr);
+}
+
+AsyncAudioProcessing::AsyncAudioProcessing(
+    AudioFrameProcessor& frame_processor,
+    TaskQueueFactory& task_queue_factory,
+    AudioFrameProcessor::OnAudioFrameCallback on_frame_processed_callback)
+    : on_frame_processed_callback_(std::move(on_frame_processed_callback)),
+      frame_processor_(frame_processor),
+      task_queue_(task_queue_factory.CreateTaskQueue(
+          "AsyncAudioProcessing",
+          TaskQueueFactory::Priority::NORMAL)) {
+  frame_processor_.SetSink([this](std::unique_ptr<AudioFrame> frame) {
+    task_queue_.PostTask([this, frame = std::move(frame)]() mutable {
+      on_frame_processed_callback_(std::move(frame));
+    });
+  });
+}
+
+void AsyncAudioProcessing::Process(std::unique_ptr<AudioFrame> frame) {
+  task_queue_.PostTask([this, frame = std::move(frame)]() mutable {
+    frame_processor_.Process(std::move(frame));
+  });
+}
+
+}  // namespace webrtc