content/renderer/media/renderer_webaudiodevice_impl.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "content/renderer/media/renderer_webaudiodevice_impl.h"
   6
   7 #include "base/command_line.h"
   8 #include "base/logging.h"
   9 #include "content/renderer/media/audio_device_factory.h"
  10 #include "content/renderer/render_frame_impl.h"
  11 #include "content/renderer/render_view_impl.h"
  12 #include "media/audio/audio_output_device.h"
  13 #include "media/base/media_switches.h"
  14 #include "third_party/WebKit/public/web/WebLocalFrame.h"
  15 #include "third_party/WebKit/public/web/WebView.h"
  16
  17 using blink::WebAudioDevice;
  18 using blink::WebLocalFrame;
  19 using blink::WebVector;
  20 using blink::WebView;
  21
  22 namespace content {
  23
  24 RendererWebAudioDeviceImpl::RendererWebAudioDeviceImpl(
  25     const media::AudioParameters& params,
  26     WebAudioDevice::RenderCallback* callback,
  27     int session_id)
  28     : params_(params),
  29       client_callback_(callback),
  30       session_id_(session_id) {
  31   DCHECK(client_callback_);
  32 }
  33
  34 RendererWebAudioDeviceImpl::~RendererWebAudioDeviceImpl() {
  35   DCHECK(!output_device_.get());
  36 }
  37
  38 void RendererWebAudioDeviceImpl::start() {
  39   DCHECK(thread_checker_.CalledOnValidThread());
  40
  41   if (output_device_.get())
  42     return;  // Already started.
  43
  44   // Assumption: This method is being invoked within a V8 call stack.  CHECKs
  45   // will fail in the call to frameForCurrentContext() otherwise.
  46   //
  47   // Therefore, we can perform look-ups to determine which RenderView is
  48   // starting the audio device.  The reason for all this is because the creator
  49   // of the WebAudio objects might not be the actual source of the audio (e.g.,
  50   // an extension creates a object that is passed and used within a page).
  51   WebLocalFrame* const web_frame = WebLocalFrame::frameForCurrentContext();
  52   WebView* const web_view = web_frame ? web_frame->view() : NULL;
  53   RenderFrame* const render_frame =
  54       web_frame ? RenderFrame::FromWebFrame(web_frame) : NULL;
  55   RenderViewImpl* const render_view =
  56       web_view ? RenderViewImpl::FromWebView(web_view) : NULL;
  57   output_device_ = AudioDeviceFactory::NewOutputDevice(
  58       render_view ? render_view->routing_id() : MSG_ROUTING_NONE,
  59       render_frame ? render_frame->GetRoutingID(): MSG_ROUTING_NONE);
  60   output_device_->InitializeWithSessionId(params_, this, session_id_);
  61   output_device_->Start();
  62   // Note: Default behavior is to auto-play on start.
  63 }
  64
  65 void RendererWebAudioDeviceImpl::stop() {
  66   DCHECK(thread_checker_.CalledOnValidThread());
  67
  68   if (output_device_.get()) {
  69     output_device_->Stop();
  70     output_device_ = NULL;
  71   }
  72 }
  73
  74 double RendererWebAudioDeviceImpl::sampleRate() {
  75   return params_.sample_rate();
  76 }
  77
  78 int RendererWebAudioDeviceImpl::Render(media::AudioBus* dest,
  79                                        int audio_delay_milliseconds) {
  80   if (client_callback_) {
  81     // Wrap the output pointers using WebVector.
  82     WebVector<float*> web_audio_dest_data(
  83         static_cast<size_t>(dest->channels()));
  84     for (int i = 0; i < dest->channels(); ++i)
  85       web_audio_dest_data[i] = dest->channel(i);
  86
  87     // TODO(xians): Remove the following |web_audio_source_data| after
  88     // changing the blink interface.
  89     WebVector<float*> web_audio_source_data(static_cast<size_t>(0));
  90     client_callback_->render(web_audio_source_data,
  91                              web_audio_dest_data,
  92                              dest->frames());
  93   }
  94
  95   return dest->frames();
  96 }
  97
  98 void RendererWebAudioDeviceImpl::OnRenderError() {
  99   // TODO(crogers): implement error handling.
 100 }
 101
 102 }  // namespace content