add audio-buffer-size command line flag support to the input audio for all the platforms

media/audio/audio_input_proxy.cc

Index: media/audio/audio_input_proxy.cc
diff --git a/media/audio/audio_input_proxy.cc b/media/audio/audio_input_proxy.cc
new file mode 100644
index 0000000000000000000000000000000000000000..988a412db30f62c3415a0fbe39d7a0c1764b92c6
--- /dev/null
+++ b/media/audio/audio_input_proxy.cc
@@ -0,0 +1,182 @@
+// Copyright 2014 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/audio_input_proxy.h"
+
+#include "base/logging.h"
+#include "base/time/time.h"
+#include "media/audio/audio_manager_base.h"
+#include "media/base/audio_fifo.h"
+
+namespace media {
+
+AudioInputProxy::AudioInputProxy(AudioManagerBase* manager,
+                                 const AudioParameters& input_params,
+                                 const AudioParameters& output_params,
+                                 const std::string& device_id)
+    : audio_manager_(manager),
+      stream_(NULL),
+      input_params_(input_params),
+      output_params_(output_params),
+      device_id_(device_id),
+      callback_(NULL),
+      opened_(false),
+      agc_enabled_(false) {
+  DCHECK(input_params.IsValid());
+  DCHECK(output_params.IsValid());
+  DCHECK_EQ(output_params_.format(), AudioParameters::AUDIO_PCM_LOW_LATENCY);
+
+  Initialize(input_params);
+}
+
+AudioInputProxy::~AudioInputProxy() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  Close();
+}
+
+void AudioInputProxy::MaybeRestartStream(const AudioParameters& input_params) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  // Do nothing if the required input formats are the same.
+  if (input_params == input_params_)
+    return;
+
+  // Do nothing if |stream_| has already been closed, which means this proxy
+  // is idle.
+  if (!stream_)
+    return;
+
+  // Cache the |callback_| because Stop() will set it to NULL>
+  AudioInputStream::AudioInputCallback* callback = callback_;
+
+  // Stop and Close the old stream.
+  Stop();
+  Close();
+  DCHECK(!stream_);
+
+  // Initialize the new stream.
+  Initialize(input_params);
+
+  // Create and restore the previous state for the new stream.
+  if (opened_)
+    Open();
+
+  // AGC needs to be enabled before calling Start();
+  SetAutomaticGainControl(agc_enabled_);
+
+  if (callback)
+    Start(callback);
+  DCHECK_EQ(callback, callback_);
+}
+
+void AudioInputProxy::Initialize(const AudioParameters& input_params) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  // We do not support resampling and down/up-mixing yet.
+  // TODO(xians): Implement a push model AudioConverter and support resampling.
+  DCHECK_EQ(output_params_.sample_rate(), input_params.sample_rate());
+  DCHECK_EQ(output_params_.channels(), input_params.channels());
+  DCHECK(!stream_);
+
+  input_params_ = input_params;
+
+  // Create the required audio fifo and audio bus to deal with the
+  // mismatching between the input and output params.
+  // The size of the FIFO is input buffer size + output buffer size.
+  // When the input buffer size and the output buffer size are the same, FIFO
+  // is not needed.
+  if (input_params_.frames_per_buffer() != output_params_.frames_per_buffer()) {
+    int buffer_size =
+        input_params_.frames_per_buffer() + output_params_.frames_per_buffer();
+    fifo_.reset(new media::AudioFifo(input_params_.channels(), buffer_size));
+    audio_bus_ = media::AudioBus::Create(
+        output_params_.channels(), output_params_.frames_per_buffer());
+  }
+
+  // Create a new audio input stream.
+  stream_ = audio_manager_->MakeLowLatencyInputStream(input_params, device_id_);
+}
+
+bool AudioInputProxy::Open() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!stream_);
+
+  opened_ = true;
+  return stream_->Open();
+}
+
+void AudioInputProxy::Start(AudioInputStream::AudioInputCallback* callback) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  DCHECK(!callback_ || callback_ == callback);
+
+  stream_->Start(callback);
+  callback_ = callback;
+}
+
+void AudioInputProxy::Stop() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+
+  stream_->Stop();
+  callback_ = NULL;
+}
+
+void AudioInputProxy::Close() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  if (!stream_)
+    return;
+
+  // AudioManager owns the |stream_|.
+  stream_->Close();
+  stream_ = NULL;
+}
+
+double AudioInputProxy::GetMaxVolume() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return stream_->GetMaxVolume();
+}
+
+void AudioInputProxy::SetVolume(double volume) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  stream_->SetVolume(volume);
+}
+
+double AudioInputProxy::GetVolume() {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  return stream_->GetVolume();
+}
+
+void AudioInputProxy::SetAutomaticGainControl(bool enabled) {
+  DCHECK(thread_checker_.CalledOnValidThread());
+  stream_->SetAutomaticGainControl(enabled);
+  agc_enabled_ = enabled;
+}
+
+bool AudioInputProxy::GetAutomaticGainControl() {
+  return stream_->GetAutomaticGainControl();
+}
+
+void AudioInputProxy::OnData(AudioInputStream* stream,
+                             const media::AudioBus* src,
+                             uint32 hardware_delay_bytes,
+                             double volume) {
+  // TODO(xians) We need to handle the frames changing on the fly ??
+  DCHECK_EQ(src->frames(), input_params_.frames_per_buffer());
+  if (!fifo_.get())
+    callback_->OnData(stream, src, hardware_delay_bytes, volume);
+
+  DCHECK_LE(fifo_->frames() + src->frames(), fifo_->max_frames());
+  fifo_->Push(src);
+
+  // Consume the data if the FIFO has enough data.
+  while (fifo_->frames() >= output_params_.frames_per_buffer()) {
+    fifo_->Consume(audio_bus_.get(), 0, audio_bus_->frames());
+    callback_->OnData(stream, audio_bus_.get(), hardware_delay_bytes, volume);
+  }
+}
+
+void AudioInputProxy::OnError(AudioInputStream* stream) {
+  callback_->OnError(stream);
+}
+
+
+
+}  // namespace media