Merge AudioRendererImpl and AudioRendererBase; add NullAudioSink

media/filters/null_audio_renderer.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 <algorithm>
-#include <cmath>
-
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/threading/platform_thread.h"
-#include "media/base/filter_host.h"
-#include "media/filters/null_audio_renderer.h"
-
-namespace media {
-
-// How "long" our buffer should be in terms of milliseconds.  In OnInitialize
-// we calculate the size of one second of audio data and use this number to
-// allocate a buffer to pass to FillBuffer.
-static const size_t kBufferSizeInMilliseconds = 100;
-
-NullAudioRenderer::NullAudioRenderer()
-    : AudioRendererBase(),
-      bytes_per_millisecond_(0),
-      buffer_size_(0),
-      bytes_per_frame_(0),
-      thread_("AudioThread") {
-}
-
-NullAudioRenderer::~NullAudioRenderer() {
-  DCHECK(!thread_.IsRunning());
-}
-
-void NullAudioRenderer::SetVolume(float volume) {
-  // Do nothing.
-}
-
-bool NullAudioRenderer::OnInitialize(int bits_per_channel,
-                                     ChannelLayout channel_layout,
-                                     int sample_rate) {
-  // Calculate our bytes per millisecond value and allocate our buffer.
-  int channels = ChannelLayoutToChannelCount(channel_layout);
-  int bytes_per_channel = bits_per_channel / 8;
-  bytes_per_frame_ = channels * bytes_per_channel;
-
-  bytes_per_millisecond_ = (bytes_per_frame_ * sample_rate) /
-      base::Time::kMillisecondsPerSecond;
-
-  buffer_size_ =
-      bytes_per_millisecond_ * kBufferSizeInMilliseconds;
-
-  buffer_.reset(new uint8[buffer_size_]);
-  DCHECK(buffer_.get());
-
-  if (!thread_.Start())
-    return false;
-
-  thread_.message_loop()->PostTask(FROM_HERE, base::Bind(
-      &NullAudioRenderer::FillBufferTask, this));
-  return true;
-}
-
-void NullAudioRenderer::OnStop() {
-  thread_.Stop();
-}
-
-void NullAudioRenderer::FillBufferTask() {
-  base::TimeDelta delay;
-
-  // Only consume buffers when actually playing.
-  if (GetPlaybackRate() > 0.0f)  {
-    size_t requested_frames = buffer_size_ / bytes_per_frame_;
-    size_t frames = FillBuffer(
-        buffer_.get(), requested_frames, base::TimeDelta());
-    size_t bytes = frames * bytes_per_frame_;
-
-    // Calculate our sleep duration, taking playback rate into consideration.
-    delay = base::TimeDelta::FromMilliseconds(
-        bytes / (bytes_per_millisecond_ * GetPlaybackRate()));
-  } else {
-    // If paused, sleep for 10 milliseconds before polling again.
-    delay = base::TimeDelta::FromMilliseconds(10);
-  }
-
-  // Sleep for at least one millisecond so we don't spin the CPU.
-  MessageLoop::current()->PostDelayedTask(
-      FROM_HERE,
-      base::Bind(&NullAudioRenderer::FillBufferTask, this),
-      std::max(delay, base::TimeDelta::FromMilliseconds(1)));
-}
-
-void NullAudioRenderer::OnRenderEndOfStream() {
-  SignalEndOfStream();
-}
-
-}  // namespace media