content/renderer/pepper/pepper_media_stream_audio_track_host.h

   1 // Copyright 2014 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 #ifndef CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_
   6 #define CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_
   7
   8 #include <deque>
   9
  10 #include "base/compiler_specific.h"
  11 #include "base/memory/scoped_ptr.h"
  12 #include "base/memory/weak_ptr.h"
  13 #include "base/synchronization/lock.h"
  14 #include "base/threading/thread_checker.h"
  15 #include "content/public/renderer/media_stream_audio_sink.h"
  16 #include "content/renderer/pepper/pepper_media_stream_track_host_base.h"
  17 #include "media/audio/audio_parameters.h"
  18 #include "ppapi/host/host_message_context.h"
  19 #include "ppapi/shared_impl/media_stream_audio_track_shared.h"
  20 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
  21
  22 namespace base {
  23 class MessageLoopProxy;
  24 }  // namespace base
  25
  26 namespace content {
  27
  28 class PepperMediaStreamAudioTrackHost : public PepperMediaStreamTrackHostBase {
  29  public:
  30   PepperMediaStreamAudioTrackHost(RendererPpapiHost* host,
  31                                   PP_Instance instance,
  32                                   PP_Resource resource,
  33                                   const blink::WebMediaStreamTrack& track);
  34
  35  private:
  36   // A helper class for receiving audio samples in the audio thread.
  37   // This class is created and destroyed on the renderer main thread.
  38   class AudioSink : public MediaStreamAudioSink {
  39    public:
  40     explicit AudioSink(PepperMediaStreamAudioTrackHost* host);
  41     ~AudioSink() override;
  42
  43     // Enqueues a free buffer index into |buffers_| which will be used for
  44     // sending audio samples to plugin.
  45     // This function is called on the main thread.
  46     void EnqueueBuffer(int32_t index);
  47
  48     // This function is called on the main thread.
  49     int32_t Configure(int32_t number_of_buffers, int32_t duration,
  50                       const ppapi::host::ReplyMessageContext& context);
  51
  52     // Send a reply to the currently pending |Configure()| request.
  53     void SendConfigureReply(int32_t result);
  54
  55     // MediaStreamAudioSink overrides:
  56     // These two functions should be called on the audio thread.
  57     // NOTE: For this specific instance, |OnSetFormat()| is also called on the
  58     // main thread. However, the call to |OnSetFormat()| happens before this
  59     // sink is added to an audio track, also on the main thread, which should
  60     // avoid any potential races.
  61     void OnData(const media::AudioBus& audio_bus,
  62                 base::TimeTicks estimated_capture_time) override;
  63     void OnSetFormat(const media::AudioParameters& params) override;
  64
  65    private:
  66     // Initializes buffers on the main thread.
  67     void SetFormatOnMainThread(int bytes_per_second, int bytes_per_frame);
  68
  69     void InitBuffers();
  70
  71     // Send enqueue buffer message on the main thread.
  72     void SendEnqueueBufferMessageOnMainThread(int32_t index,
  73                                               int32_t buffers_generation);
  74
  75     // Unowned host which is available during the AudioSink's lifespan.
  76     // It is mainly used in the main thread. But the audio thread will use
  77     // host_->buffer_manager() to read some buffer properties. It is safe
  78     // because the buffer_manager()'s properties will not be changed after
  79     // initialization.
  80     PepperMediaStreamAudioTrackHost* host_;
  81
  82     // The estimated capture time of the first sample frame of audio. This is
  83     // used as the timebase to compute the buffer timestamps.
  84     // Access only on the audio thread.
  85     base::TimeTicks first_frame_capture_time_;
  86
  87     // The current audio parameters.
  88     // Access only on the audio thread.
  89     media::AudioParameters audio_params_;
  90
  91     // Index of the currently active buffer.
  92     // Access only on the audio thread.
  93     int active_buffer_index_;
  94
  95     // Generation of buffers corresponding to the currently active
  96     // buffer. Used to make sure the active buffer is still valid.
  97     // Access only on the audio thread.
  98     int32_t active_buffers_generation_;
  99
 100     // Current offset, in sample frames, within the currently active buffer.
 101     // Access only on the audio thread.
 102     int active_buffer_frame_offset_;
 103
 104     // A lock to protect the index queue |buffers_|, |buffers_generation_|,
 105     // buffers in |host_->buffer_manager()|, and |output_buffer_size_|.
 106     base::Lock lock_;
 107
 108     // A queue for free buffer indices.
 109     std::deque<int32_t> buffers_;
 110
 111     // Generation of buffers. It is increased by every |InitBuffers()| call.
 112     int32_t buffers_generation_;
 113
 114     // Intended size of each output buffer.
 115     int32_t output_buffer_size_;
 116
 117     scoped_refptr<base::MessageLoopProxy> main_message_loop_proxy_;
 118
 119     base::ThreadChecker audio_thread_checker_;
 120
 121     // Number of buffers.
 122     int32_t number_of_buffers_;
 123
 124     // Number of bytes per second.
 125     int bytes_per_second_;
 126
 127     // Number of bytes per frame = channels * bytes per sample.
 128     int bytes_per_frame_;
 129
 130     // User-configured buffer duration, in milliseconds.
 131     int32_t user_buffer_duration_;
 132
 133     // Pending |Configure()| reply context.
 134     ppapi::host::ReplyMessageContext pending_configure_reply_;
 135
 136     base::WeakPtrFactory<AudioSink> weak_factory_;
 137
 138     DISALLOW_COPY_AND_ASSIGN(AudioSink);
 139   };
 140
 141   ~PepperMediaStreamAudioTrackHost() override;
 142
 143   // ResourceMessageHandler overrides:
 144   int32_t OnResourceMessageReceived(
 145       const IPC::Message& msg,
 146       ppapi::host::HostMessageContext* context) override;
 147
 148   // Message handlers:
 149   int32_t OnHostMsgConfigure(
 150       ppapi::host::HostMessageContext* context,
 151       const ppapi::MediaStreamAudioTrackShared::Attributes& attributes);
 152
 153   // PepperMediaStreamTrackHostBase overrides:
 154   void OnClose() override;
 155
 156   // MediaStreamBufferManager::Delegate overrides:
 157   void OnNewBufferEnqueued() override;
 158
 159   // ResourceHost overrides:
 160   void DidConnectPendingHostToResource() override;
 161
 162   blink::WebMediaStreamTrack track_;
 163
 164   // True if |audio_sink_| has been added to |blink::WebMediaStreamTrack|
 165   // as a sink.
 166   bool connected_;
 167
 168   AudioSink audio_sink_;
 169
 170   DISALLOW_COPY_AND_ASSIGN(PepperMediaStreamAudioTrackHost);
 171 };
 172
 173 }  // namespace content
 174
 175 #endif  // CONTENT_RENDERER_PEPPER_PEPPER_MEDIA_STREAM_AUDIO_TRACK_HOST_H_