ppapi/cpp/audio.h

   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 #ifndef PPAPI_CPP_AUDIO_H_
   6 #define PPAPI_CPP_AUDIO_H_
   7
   8 #include "ppapi/c/pp_stdint.h"
   9 #include "ppapi/c/ppb_audio.h"
  10 #include "ppapi/cpp/audio_config.h"
  11 #include "ppapi/cpp/resource.h"
  12
  13 /// @file
  14 /// This file defines the API to create realtime stereo audio streaming
  15 /// capabilities.
  16
  17 namespace pp {
  18
  19 class InstanceHandle;
  20
  21 /// An audio resource. Refer to the
  22 /// <a href="/native-client/devguide/coding/audio">Audio</a>
  23 /// chapter in the Developer's Guide for information on using this interface.
  24 class Audio : public Resource {
  25  public:
  26
  27   /// An empty constructor for an Audio resource.
  28   Audio() {}
  29
  30   /// A constructor that creates an Audio resource. No sound will be heard
  31   /// until StartPlayback() is called. The callback is called with the buffer
  32   /// address and given user data whenever the buffer needs to be filled.
  33   /// From within the callback, you should not call <code>PPB_Audio</code>
  34   /// functions. The callback will be called on a different thread than the one
  35   /// which created the interface. For performance-critical applications (such
  36   /// as low-latency audio), the callback should avoid blocking or calling
  37   /// functions that can obtain locks, such as malloc. The layout and the size
  38   /// of the buffer passed to the audio callback will be determined by
  39   /// the device configuration and is specified in the <code>AudioConfig</code>
  40   /// documentation.
  41   ///
  42   /// @param[in] instance The instance with which this resource will be
  43   /// associated.
  44   //
  45   /// @param[in] config An <code>AudioConfig</code> containing the audio config
  46   /// resource.
  47   //
  48   /// @param[in] callback A <code>PPB_Audio_Callback</code> callback function
  49   /// that the browser calls when it needs more samples to play.
  50   //
  51   /// @param[in] user_data A pointer to user data used in the callback function.
  52   Audio(const InstanceHandle& instance,
  53         const AudioConfig& config,
  54         PPB_Audio_Callback callback,
  55         void* user_data);
  56
  57   /// Getter function for returning the internal <code>PPB_AudioConfig</code>
  58   /// struct.
  59   ///
  60   /// @return A mutable reference to the PPB_AudioConfig struct.
  61   AudioConfig& config() { return config_; }
  62
  63   /// Getter function for returning the internal <code>PPB_AudioConfig</code>
  64   /// struct.
  65   ///
  66   /// @return A const reference to the internal <code>PPB_AudioConfig</code>
  67   /// struct.
  68   const AudioConfig& config() const { return config_; }
  69
  70   /// StartPlayback() starts playback of audio.
  71   ///
  72   /// @return true if successful, otherwise false.
  73   bool StartPlayback();
  74
  75   /// StopPlayback stops playback of audio.
  76   ///
  77   /// @return true if successful, otherwise false.
  78   bool StopPlayback();
  79
  80  private:
  81   AudioConfig config_;
  82 };
  83
  84 }  // namespace pp
  85
  86 #endif  // PPAPI_CPP_AUDIO_H_
  87