AMicrophone.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#ifndef META_OCEAN_MEDIA_ANDROID_A_MICROPHONE_H
#define META_OCEAN_MEDIA_ANDROID_A_MICROPHONE_H
 
#include "ocean/media/android/Android.h"
#include "ocean/media/android/AMedium.h"
 
#include "ocean/media/Microphone.h"
 
#include <SLES/OpenSLES_Android.h>
 
#include <queue>
 
namespace Ocean
{
 
namespace Media
{
 
namespace Android
{
 
/**
 * This class implements a microphone class for Android.
 * @ingroup mediaandroid
 */
class OCEAN_MEDIA_A_EXPORT AMicrophone final :
    virtual public AMedium,
    virtual public Microphone
{
    friend class ALibrary;
 
    protected:
 
        /// The number of buffers in the queue.
        static constexpr SLuint32 numberBuffers_ = 4u;
 
        /**
         * Definition of a vector holding sample elements.
         */
        typedef std::vector<int16_t> Buffer;
 
    public:
 
        /**
         * Starts the medium.
         * @see Medium::start().
         */
        bool start() override;
 
        /**
         * Pauses the medium.
         * @see Medium::pause():
         */
        bool pause() override;
 
        /**
         * Stops the medium.
         * @see Medium::stop().
         */
        bool stop() override;
 
        /**
         * Returns whether the medium is started currently.
         * @see Medium::isStarted().
         */
        bool isStarted() const override;
 
        /**
         * Returns the start timestamp.
         * @see FiniteMedium::startTimestamp().
         */
        Timestamp startTimestamp() const override;
 
        /**
         * Returns the pause timestamp.
         * @see FiniteMedium::pauseTimestamp().
         */
        Timestamp pauseTimestamp() const override;
 
        /**
         * Returns the stop timestamp.
         * @see FiniteMedium::stopTimestamp().
         */
        Timestamp stopTimestamp() const override;
 
        /**
         * Returns the size of one mono chunk in elements.
         * @return The size of one mono chunk, in elements
         */
        static constexpr size_t monoChunkElements();
 
    protected:
 
        /**
         * Creates a new medium by a given url.
         * @param slEngineInterface The interface of the SL engine, must be valid
         * @param url Url of the medium
         */
        AMicrophone(const SLEngineItf& slEngineInterface, const std::string& url);
 
        /**
         * Destructs the live video object.
         */
        ~AMicrophone() override;
 
        /**
         * Initializes the audio and all corresponding resources.
         * @param slEngineInterface The interface of the SL engine, must be valid
         * @param microphoneTypes The types of the microphone to create
         * @param microphoneConfigurations The configurations of the microphone to create
         * @return True, if succeeded
         */
        bool initialize(const SLEngineItf& slEngineInterface, const MicrophoneTypes microphoneTypes, const MicrophoneConfigurations microphoneConfigurations);
 
        /**
         * Releases the audio and all corresponding resources.
         * @return True, if succeeded
         */
        bool release();
 
        /**
         * Event callback function to fill the OpenSL buffer queue.
         * @param bufferQueue The buffer queue to fill with the next samples, must be valid
         */
        void onFillBufferQueueCallback(SLAndroidSimpleBufferQueueItf bufferQueue);
 
        /**
         * Static event callback function to fill the OpenSL buffer queue.
         * @param bufferQueue The buffer queue to fill with the next samples, must be valid
         * @param context The context of the event (the ALiveAudio object), must be valid
         */
        static void onFillBufferQueueCallback(SLAndroidSimpleBufferQueueItf bufferQueue, void* context);
 
    protected:
 
        /// Start timestamp.
        Timestamp startTimestamp_ = Timestamp(false);
 
        /// Pause timestamp.
        Timestamp pauseTimestamp_ = Timestamp(false);
 
        /// Stop timestamp.
        Timestamp stopTimestamp_ = Timestamp(false);
 
        /// The SL recorder object.
        SLObjectItf slRecorder_ = nullptr;
 
        /// The SL recorder interface.
        SLRecordItf slRecordInterface_ = nullptr;
 
        /// THe SL buffer queue interface.
        SLAndroidSimpleBufferQueueItf slBufferQueueInterface_ = nullptr;
 
        /// The buffer for the sample queue.
        std::queue<Buffer> bufferQueue_;
 
        /// The SL effect interface for the acoustic echo cancel effect.
        SLAndroidEffectItf slAcousticEchoCancelEffect_ = nullptr;
 
        /// The SL implementation id of the acoustic echo cancel effect.
        SLInterfaceID slAcousticEchoCancelerEffectImplementationId_ = nullptr;
};
 
constexpr size_t AMicrophone::monoChunkElements()
{
    constexpr size_t samplesPerSecondMono = 48000; // 48kHz
 
    return samplesPerSecondMono / 50; // 20ms
}
 
}
 
}
 
}
 
#endif // META_OCEAN_MEDIA_ANDROID_A_MICROPHONE_H