Experimental: Unmute Audio During Tab Sourced Desktop Share

media/audio/virtual_audio_output_stream.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "media/audio/virtual_audio_output_stream.h"
 
 #include <stdint.h>
 
 #include "base/logging.h"
 #include "media/audio/virtual_audio_input_stream.h"
@@ skipping 73 matching lines @@
                                           buffer_delay /
                                           base::TimeDelta::FromSeconds(1);
   const int frames = callback_->OnMoreData(
       audio_bus, static_cast<uint32_t>(upstream_delay_in_bytes), 0);
   if (frames < audio_bus->frames())
     audio_bus->ZeroFramesPartial(frames, audio_bus->frames() - frames);
 
   return frames > 0 ? volume_ : 0;
 }
 
+static const base::TimeDelta kBufferSize = base::TimeDelta::FromSeconds(1);
+static const base::TimeDelta kClockAccuracy =
+    base::TimeDelta::FromMilliseconds(1);
+static const base::TimeDelta kAdjustTime = base::TimeDelta::FromSeconds(1);
+
+LoopbackSink::LoopbackSink(AudioParameters param,
+                           VirtualAudioInputStream* target,
+                           AfterCloseCallback callback)
+    : started_(false),
+      params_(param),
+      target_(target),
+      shifter_(new AudioShifter(kBufferSize,
+                                kClockAccuracy,
+                                kAdjustTime,
+                                param.sample_rate(),
+                                param.channels())),
+      after_close_callback_(callback) {}
+
+LoopbackSink::~LoopbackSink() {}
+
+void LoopbackSink::Start() {
+  started_ = true;
+  target_->AddOutputStream(this, params_);
+}
+
+void LoopbackSink::Stop() {
+  target_->RemoveOutputStream(this, params_);
+  started_ = false;
+}
+
+void LoopbackSink::Close() {
+  if (started_)
+    Stop();
+  AfterCloseCallback cb = after_close_callback_;
+  if (!cb.is_null())
+    cb.Run(this);
+}
+
+void LoopbackSink::OnData(AudioInputStream* stream,
+                          const AudioBus* source,
+                          uint32_t hardware_delay_bytes,
+                          double volume) {
+  printf("Sink: Input Data\n");
+  std::unique_ptr<AudioBus> source_copy = AudioBus::Create(params_);
+  source->CopyTo(source_copy.get());
+  shifter_->Push(std::move(source_copy), base::TimeTicks::Now());
+}
+
+void LoopbackSink::OnError(AudioInputStream* stream) {}
+
+double LoopbackSink::ProvideInput(AudioBus* audio_bus,
+                                  base::TimeDelta buffer_delay) {
+  printf("Sink: Output Data Start\n");
+  shifter_->Pull(audio_bus, base::TimeTicks::Now());
+  printf("Sink: Output Data Finish\n");
+  return 1;
+}
+
 }  // namespace media