C++ setVolume函数代码示例

 void
 Movie::play() {
     AC_INFO << "playing movie: "<< getSrc() << " (volume: " << _volume <<")";
     masl::MovieEngineSingleton::get().getNative()->playMovie(this);
     setVolume(_volume);
 }

void MusicNode::unsetPanTrack() {
	_pantrack = false;
	setVolume(_volume);
}

static void
spk_setVolume (volatile SpeechSynthesizer *spk, unsigned char setting) {
  setVolume(getIntegerSpeechVolume(setting, 100));
}

status_t BnMediaPlayer::onTransact(
    uint32_t code, const Parcel& data, Parcel* reply, uint32_t flags)
{
    switch(code) {
        case DISCONNECT: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            disconnect();
            return NO_ERROR;
        } break;
        case SET_VIDEO_SURFACE: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            sp<ISurface> surface = interface_cast<ISurface>(data.readStrongBinder());
            reply->writeInt32(setVideoSurface(surface));
            return NO_ERROR;
        } break;
        case PREPARE_ASYNC: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(prepareAsync());
            return NO_ERROR;
        } break;
        case START: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(start());
            return NO_ERROR;
        } break;
        case STOP: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(stop());
            return NO_ERROR;
        } break;
        case IS_PLAYING: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            bool state;
            status_t ret = isPlaying(&state);
            reply->writeInt32(state);
            reply->writeInt32(ret);
            return NO_ERROR;
        } break;
        case PAUSE: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(pause());
            return NO_ERROR;
        } break;
        case SEEK_TO: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(seekTo(data.readInt32()));
            return NO_ERROR;
        } break;
        case GET_CURRENT_POSITION: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            int msec;
            status_t ret = getCurrentPosition(&msec);
            reply->writeInt32(msec);
            reply->writeInt32(ret);
            return NO_ERROR;
        } break;
        case GET_DURATION: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            int msec;
            status_t ret = getDuration(&msec);
            reply->writeInt32(msec);
            reply->writeInt32(ret);
            return NO_ERROR;
        } break;
        case RESET: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(reset());
            return NO_ERROR;
        } break;
        case SET_AUDIO_STREAM_TYPE: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(setAudioStreamType(data.readInt32()));
            return NO_ERROR;
        } break;
        case SET_LOOPING: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(setLooping(data.readInt32()));
            return NO_ERROR;
        } break;
        case SET_VOLUME: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(setVolume(data.readFloat(), data.readFloat()));
            return NO_ERROR;
        } break;
        case INVOKE: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            invoke(data, reply);
            return NO_ERROR;
        } break;
        case SET_METADATA_FILTER: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(setMetadataFilter(data));
            return NO_ERROR;
        } break;
        case SUSPEND: {
            CHECK_INTERFACE(IMediaPlayer, data, reply);
            reply->writeInt32(suspend());
            return NO_ERROR;
        } break;
        case RESUME: {
//.........这里部分代码省略.........

bool BaseSoundMgr::setVolumePercent(Audio::Mixer::SoundType type, byte percent) {
	return setVolume(type, percent * 255 / 100);
}

bool AudioDecoder::resample()
{
    if (_result.sampleRate == _sampleRate)
    {
        ALOGI("No need to resample since the sample rate (%d) of the decoded pcm data is the same as the device output sample rate",
              _sampleRate);
        return true;
    }

    ALOGV("Resample: %d --> %d", _result.sampleRate, _sampleRate);

    auto r = _result;
    PcmBufferProvider provider;
    provider.init(r.pcmBuffer->data(), r.numFrames, r.pcmBuffer->size() / r.numFrames);

    const int outFrameRate = _sampleRate;
    int outputChannels = 2;
    size_t outputFrameSize = outputChannels * sizeof(int32_t);
    size_t outputFrames = ((int64_t) r.numFrames * outFrameRate) / r.sampleRate;
    size_t outputSize = outputFrames * outputFrameSize;
    void *outputVAddr = malloc(outputSize);

    auto resampler = AudioResampler::create(AUDIO_FORMAT_PCM_16_BIT, r.numChannels, outFrameRate,
                                            AudioResampler::MED_QUALITY);
    resampler->setSampleRate(r.sampleRate);
    resampler->setVolume(AudioResampler::UNITY_GAIN_FLOAT, AudioResampler::UNITY_GAIN_FLOAT);

    memset(outputVAddr, 0, outputSize);

    ALOGV("resample() %zu output frames", outputFrames);

    std::vector<int> Ovalues;

    if (Ovalues.empty())
    {
        Ovalues.push_back(outputFrames);
    }
    for (size_t i = 0, j = 0; i < outputFrames;)
    {
        size_t thisFrames = Ovalues[j++];
        if (j >= Ovalues.size())
        {
            j = 0;
        }
        if (thisFrames == 0 || thisFrames > outputFrames - i)
        {
            thisFrames = outputFrames - i;
        }
        int outFrames = resampler->resample((int *) outputVAddr + outputChannels * i, thisFrames,
                                            &provider);
        ALOGV("outFrames: %d", outFrames);
        i += thisFrames;
    }

    ALOGV("resample() complete");

    resampler->reset();

    ALOGV("reset() complete");

    delete resampler;
    resampler = nullptr;

    // mono takes left channel only (out of stereo output pair)
    // stereo and multichannel preserve all channels.

    int channels = r.numChannels;
    int32_t *out = (int32_t *) outputVAddr;
    int16_t *convert = (int16_t *) malloc(outputFrames * channels * sizeof(int16_t));

    const int volumeShift = 12; // shift requirement for Q4.27 to Q.15
    // round to half towards zero and saturate at int16 (non-dithered)
    const int roundVal = (1 << (volumeShift - 1)) - 1; // volumePrecision > 0

    for (size_t i = 0; i < outputFrames; i++)
    {
        for (int j = 0; j < channels; j++)
        {
            int32_t s = out[i * outputChannels + j] + roundVal; // add offset here
            if (s < 0)
            {
                s = (s + 1) >> volumeShift; // round to 0
                if (s < -32768)
                {
                    s = -32768;
                }
            } else
            {
                s = s >> volumeShift;
                if (s > 32767)
                {
                    s = 32767;
                }
            }
            convert[i * channels + j] = int16_t(s);
        }

SinOsc::SinOsc(float freq, float volume) {
	phase 				= 0.0f;
	setFreq(freq);
	setVolume(volume);
}

void hammerMain() {

    uprint("\r\n ######################## BOOT UP (HAMMER) ######################## \r\n");

    initHammerState();
    HammerState *hs = getHammerStatePtr();

    configureAccelerometer();

    configureAudio();
    audioReset();

    int sta = configureRadio(0x0A00, 0x0000111111111111);
    uprint_int("Configured radio: ", sta);

    configureIRReceive();

    configureLightMCU_SPI();

    updateLightMCUAll(hs->health, hs->charge);

    char sendString[2] = "x";
    char rxbuf[50];
    char doneString[] = "DONE";

    DELAY_MS(400);

    playSound(HS_BOOT);
    DELAY_MS(HS_BOOT_LEN);
    
    while (1) {

        uprint("Beginning of main loop");
        hs->charge = 0;
        updateLightMCUAll(hs->health, hs->charge);

        uprint("Waiting for spin...");
        startTrackingSpin();
        while (!checkSpinComplete());

        uprint("Spin complete!");
        playSound(HS_SPINCOMPLETE);
        DELAY_MS(HS_SPINCOMPLETE_LEN);

        setVolume(5);
        // Charging is really damn loud

        // This sound is very long, we just start it playing
        playSound(HS_CHARGING);

        uprint("Charging ...");

        hs->charge = 0;
        hs->charging = 1;
        while (hs->charge < 100) {
            hs->charge ++;
            updateLightMCUCharge(hs->charge);
            DELAY_MS((0.9 * hs->health) + 10);
        }
        hs->charging = 0;

        setVolume(8);
        // Back to normal

        playSound(HS_CHARGECOMPLETE);
        DELAY_MS(HS_CHARGECOMPLETE_LEN);

        uprint("Finished charging!");

        uprint("Waiting for thrust...");
        startTrackingThrust();
        while (!checkThrustComplete());

        setLightMCUHitAnim();

        uprint("Thrust complete!");
        playSound(HS_FIRE);
        DELAY_MS(HS_FIRE_LEN);

        setLightMCURainbow();

        // Become invincible
        disableIRReceive();

        uprint("Sending radio message");
        sendString[0] = hs->health;
        radioSendMessage(sendString, 0x0A00);

        uprint("Waiting for cloud message");
        radioGetMessage(rxbuf, 50);

        if (memcmp(rxbuf, doneString, 4) != 0) {
            uprint("Invalid message from cloud!");
        }

        enableIRReceive();
        uprint("Got cloud message");


        setLightMCUOff();
//.........这里部分代码省略.........

bool UrlAudioPlayer::prepare(const std::string &url, SLuint32 locatorType, std::shared_ptr<AssetFd> assetFd, int start,
                             int length)
{
    _url = url;
    _assetFd = assetFd;

    const char* locatorTypeStr= "UNKNOWN";
    if (locatorType == SL_DATALOCATOR_ANDROIDFD)
        locatorTypeStr = "SL_DATALOCATOR_ANDROIDFD";
    else if (locatorType == SL_DATALOCATOR_URI)
        locatorTypeStr = "SL_DATALOCATOR_URI";
    else
    {
        ALOGE("Oops, invalid locatorType: %d", (int)locatorType);
        return false;
    }

    ALOGV("UrlAudioPlayer::prepare: %s, %s, %d, %d, %d", _url.c_str(), locatorTypeStr, _assetFd->getFd(), start,
         length);
    SLDataSource audioSrc;

    SLDataFormat_MIME formatMime = {SL_DATAFORMAT_MIME, nullptr, SL_CONTAINERTYPE_UNSPECIFIED};
    audioSrc.pFormat = &formatMime;

    //Note: locFd & locUri should be outside of the following if/else block
    // Although locFd & locUri are only used inside if/else block, its lifecycle
    // will be destroyed right after '}' block. And since we pass a pointer to
    // 'audioSrc.pLocator=&locFd/&locUri', pLocator will point to an invalid address
    // while invoking Engine::createAudioPlayer interface. So be care of change the position
    // of these two variables.
    SLDataLocator_AndroidFD locFd;
    SLDataLocator_URI locUri;

    if (locatorType == SL_DATALOCATOR_ANDROIDFD)
    {
        locFd = {locatorType, _assetFd->getFd(), start, length};
        audioSrc.pLocator = &locFd;
    }
    else if (locatorType == SL_DATALOCATOR_URI)
    {
        locUri = {locatorType, (SLchar *) _url.c_str()};
        audioSrc.pLocator = &locUri;
        ALOGV("locUri: locatorType: %d", (int)locUri.locatorType);
    }

    // configure audio sink
    SLDataLocator_OutputMix locOutmix = {SL_DATALOCATOR_OUTPUTMIX, _outputMixObj};
    SLDataSink audioSnk = {&locOutmix, nullptr};

    // create audio player
    const SLInterfaceID ids[3] = {SL_IID_SEEK, SL_IID_PREFETCHSTATUS, SL_IID_VOLUME};
    const SLboolean req[3] = {SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE, SL_BOOLEAN_TRUE};

    SLresult result = (*_engineItf)->CreateAudioPlayer(_engineItf, &_playObj, &audioSrc, &audioSnk,
                                                       3, ids, req);
    SL_RETURN_VAL_IF_FAILED(result, false, "CreateAudioPlayer failed");

    // realize the player
    result = (*_playObj)->Realize(_playObj, SL_BOOLEAN_FALSE);
    SL_RETURN_VAL_IF_FAILED(result, false, "Realize failed");

    // get the play interface
    result = (*_playObj)->GetInterface(_playObj, SL_IID_PLAY, &_playItf);
    SL_RETURN_VAL_IF_FAILED(result, false, "GetInterface SL_IID_PLAY failed");

    // get the seek interface
    result = (*_playObj)->GetInterface(_playObj, SL_IID_SEEK, &_seekItf);
    SL_RETURN_VAL_IF_FAILED(result, false, "GetInterface SL_IID_SEEK failed");

    // get the volume interface
    result = (*_playObj)->GetInterface(_playObj, SL_IID_VOLUME, &_volumeItf);
    SL_RETURN_VAL_IF_FAILED(result, false, "GetInterface SL_IID_VOLUME failed");

    result = (*_playItf)->RegisterCallback(_playItf,
                                           SLUrlAudioPlayerCallbackProxy::playEventCallback, this);
    SL_RETURN_VAL_IF_FAILED(result, false, "RegisterCallback failed");

    result = (*_playItf)->SetCallbackEventsMask(_playItf, SL_PLAYEVENT_HEADATEND);
    SL_RETURN_VAL_IF_FAILED(result, false, "SetCallbackEventsMask SL_PLAYEVENT_HEADATEND failed");

    setState(State::INITIALIZED);

    setVolume(1.0f);

    return true;
}

void EnginePhonon::volumeDec( )
{
    int percent = volume() > 0 ? volume() -1 : 0;
    setVolume(percent);
};

/*
********************************************************************************
*                                                                              *
*    Class EnginePhonon                                                        *
*                                                                              *
********************************************************************************
*/
EnginePhonon::EnginePhonon() : EngineBase("phonon")
{
    m_type = ENGINE::PHONON;
    
    m_mediaObject = new Phonon::MediaObject(this);
    m_audioOutput = new Phonon::AudioOutput(Phonon::MusicCategory, this);

    /* ----- by default tick every 1 second ----- */
    m_mediaObject->setTickInterval(100);
    Debug::debug() << "[EnginePhonon] -> tick Interval (actual): " << m_mediaObject->tickInterval();
    

    /* ----- get the next track when there is 2 seconds left on the current one ----- */
    /*       in case of playing track from track view */
    m_mediaObject->setPrefinishMark( 2000 );
    m_mediaObject->setTransitionTime(100);  /* GAPLESS/CROSSFADE */

    connect(m_mediaObject,SIGNAL(finished()),this,SLOT(slot_on_media_finished()));
    connect(m_mediaObject,SIGNAL(aboutToFinish()),this,SLOT(slot_on_media_about_to_finish()));

    connect(m_mediaObject,SIGNAL(stateChanged(Phonon::State,Phonon::State)),this,SLOT(slot_on_phonon_state_changed(Phonon::State,Phonon::State)),Qt::DirectConnection);

    connect(m_mediaObject,SIGNAL(tick(qint64)),this,SLOT(slot_on_time_change(qint64)));
    connect(m_mediaObject,SIGNAL(totalTimeChanged(qint64)),this,SLOT(slot_on_duration_change(qint64)));

    connect(m_mediaObject,SIGNAL(currentSourceChanged( const Phonon::MediaSource & )),this,SLOT(slot_on_media_change()));

    connect(m_mediaObject, SIGNAL(metaDataChanged()), this,SLOT(slot_on_metadata_change()));

    /* needed for Mplayer2 backend */
    connect( m_audioOutput, SIGNAL( volumeChanged( qreal ) ),this, SIGNAL( volumeChanged() ) );
    connect( m_audioOutput, SIGNAL( mutedChanged( bool ) ), this,  SIGNAL( muteStateChanged() ) );
    
    m_phononPath  = Phonon::createPath(m_mediaObject,m_audioOutput);


    /* ----- only create pre-amp if we have replaygain on, VolumeFaderEffect can cause phonon issues */
    m_preamp = 0;
    if( SETTINGS()->_replaygain != SETTING::ReplayGainOff )
    {
      m_preamp = new Phonon::VolumeFaderEffect( this );
      m_phononPath.insertEffect( m_preamp );
    }

    /* ----- add an equalizer effect if available */
    m_equalizer   = 0;
    QList<Phonon::EffectDescription> mEffectDescriptions = Phonon::BackendCapabilities::availableAudioEffects();
    foreach ( const Phonon::EffectDescription &mDescr, mEffectDescriptions )
    {
      if ( mDescr.name() == QLatin1String( "KEqualizer" ) )
      {
          m_equalizer = new Phonon::Effect( mDescr, this );

          if( SETTINGS()->_enableEq ) {
            addEqualizer();
            loadEqualizerSettings();
          }
      }
    }

    /* ----- initial volume setup ----- */
    setVolume( SETTINGS()->_volumeLevel );
        
    m_current_state    = ENGINE::STOPPED;
    m_old_state        = ENGINE::STOPPED;
    
    m_version = QString();
}

void RingControl::profileChanged()
{
    QPhoneProfile prof = d->profileManager->activeProfile();
    setVolume(prof.volume());
    setMsgRingTime(prof.msgAlertDuration());
}

void MidiPlayer::adjustVolume(int diff) {
	debugC(3, kDebugMusic, "MidiPlayer::adjustVolume");
	setVolume(_masterVolume + diff);
}

void MediaPlayer::decrementVolume()
{
    setVolume(volume()-1);
}

void AudioPlayerGnu::unmute()
{
    if(_isMuted)
        setVolume(volumeForMute);
    _isMuted=false;
}