// 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. #ifndef PPAPI_CPP_MEDIA_STREAM_AUDIO_TRACK_H_ #define PPAPI_CPP_MEDIA_STREAM_AUDIO_TRACK_H_ #include <string> #include "ppapi/c/ppb_media_stream_audio_track.h" #include "ppapi/cpp/resource.h" #include "ppapi/cpp/var.h" /// @file /// This file defines the <code>MediaStreamAudioTrack</code> interface for an /// audio source resource, which receives audio buffers from a MediaStream audio /// track in the browser. namespace pp { class AudioBuffer; class CompletionCallback; template <typename T> class CompletionCallbackWithOutput; /// The <code>MediaStreamAudioTrack</code> class contains methods for /// receiving audio buffers from a MediaStream audio track in the browser. class MediaStreamAudioTrack : public Resource { public: /// Default constructor for creating an is_null() /// <code>MediaStreamAudioTrack</code> object. MediaStreamAudioTrack(); /// The copy constructor for <code>MediaStreamAudioTrack</code>. /// /// @param[in] other A reference to a <code>MediaStreamAudioTrack</code>. MediaStreamAudioTrack(const MediaStreamAudioTrack& other); /// Constructs a <code>MediaStreamAudioTrack</code> from /// a <code>Resource</code>. /// /// @param[in] resource A <code>PPB_MediaStreamAudioTrack</code> resource. explicit MediaStreamAudioTrack(const Resource& resource); /// A constructor used when you have received a <code>PP_Resource</code> as a /// return value that has had 1 ref added for you. /// /// @param[in] resource A <code>PPB_MediaStreamAudioTrack</code> resource. MediaStreamAudioTrack(PassRef, PP_Resource resource); ~MediaStreamAudioTrack(); /// Configures underlying buffer buffers for incoming audio samples. /// If the application doesn't want to drop samples, then the /// <code>PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS</code> should be /// chosen such that inter-buffer processing time variability won't overrun /// all input buffers. If all buffers are filled, then samples will be /// dropped. The application can detect this by examining the timestamp on /// returned buffers. If <code>Configure()</code> is not called, default /// settings will be used. /// Example usage from plugin code: /// @code /// int32_t attribs[] = { /// PP_MEDIASTREAMAUDIOTRACK_ATTRIB_BUFFERS, 4, /// PP_MEDIASTREAMAUDIOTRACK_ATTRIB_DURATION, 10, /// PP_MEDIASTREAMAUDIOTRACK_ATTRIB_NONE}; /// track.Configure(attribs, callback); /// @endcode /// /// @param[in] attrib_list A list of attribute name-value pairs in which each /// attribute is immediately followed by the corresponding desired value. /// The list is terminated by /// <code>PP_MEDIASTREAMAUDIOTRACK_AUDIO_NONE</code>. /// @param[in] callback A <code>CompletionCallback</code> to be called upon /// completion of <code>Configure()</code>. /// /// @return An int32_t containing a result code from <code>pp_errors.h</code>. int32_t Configure(const int32_t attributes[], const CompletionCallback& callback); /// Gets attribute value for a given attribute name. /// /// @param[in] attrib A <code>PP_MediaStreamAudioTrack_Attrib</code> for /// querying. /// @param[out] value A int32_t for storing the attribute value. /// /// @return An int32_t containing a result code from <code>pp_errors.h</code>. int32_t GetAttrib(PP_MediaStreamAudioTrack_Attrib attrib, int32_t* value); /// Returns the track ID of the underlying MediaStream audio track. std::string GetId() const; /// Checks whether the underlying MediaStream track has ended. /// Calls to GetBuffer while the track has ended are safe to make and will /// complete, but will fail. bool HasEnded() const; /// Gets the next audio buffer from the MediaStream track. /// If internal processing is slower than the incoming buffer rate, /// new buffers will be dropped from the incoming stream. Once all buffers /// are full, audio samples will be dropped until <code>RecycleBuffer()</code> /// is called to free a spot for another buffer. /// If there are no audio data in the input buffer, /// <code>PP_OK_COMPLETIONPENDING</code> will be returned immediately and the /// <code>callback</code> will be called when a new buffer of audio samples /// is received or some error happens. /// /// @param[in] callback A <code>CompletionCallbackWithOutput</code> to be /// called upon completion of <code>GetBuffer()</code>. If success, /// an AudioBuffer will be passed into the completion callback function. /// /// @return An int32_t containing a result code from <code>pp_errors.h</code>. int32_t GetBuffer( const CompletionCallbackWithOutput<AudioBuffer>& callback); /// Recycles a buffer returned by <code>GetBuffer()</code>, so the track can /// reuse the buffer. And the buffer will become invalid. The caller should /// release all references it holds to <code>buffer</code> and not use it /// anymore. /// /// @param[in] buffer A AudioBuffer returned by <code>GetBuffer()</code>. /// /// @return An int32_t containing a result code from <code>pp_errors.h</code>. int32_t RecycleBuffer(const AudioBuffer& buffer); /// Closes the MediaStream audio track, and disconnects it from the audio /// source. /// After calling <code>Close()</code>, no new buffers will be received. void Close(); /// Checks whether a <code>Resource</code> is a MediaStream audio track, /// to test whether it is appropriate for use with the /// <code>MediaStreamAudioTrack</code> constructor. /// /// @param[in] resource A <code>Resource</code> to test. /// /// @return True if <code>resource</code> is a MediaStream audio track. static bool IsMediaStreamAudioTrack(const Resource& resource); }; } // namespace pp #endif // PPAPI_CPP_MEDIA_STREAM_AUDIO_TRACK_H_