programa - estudio de grabacion para android apk

Android: ¿Cómo crear efectos de sonido de entrada/salida gradual para cualquier archivo de música que reproduzca mi aplicación?

Question

La aplicación en la que estoy trabajando reproduce archivos de música. Si un temporizador caduca, quiero que la música se desvanezca. Cómo puedo hacer eso. Estoy usando MediaPlayer para reproducir música y los archivos de música están presentes en la carpeta sin formato de mi aplicación.

Answer 1

Aquí está mi adaptación simplificada de stock de Android Alarm Clock se desvanecen en la implementación.

En lugar de definir el número de pasos / incrementos y luego aumentar el volumen paso a paso (como en otras respuestas a esta pregunta), ajusta el volumen cada 50 ms (valor configurable) resolviendo pasos / incrementos en la escala entre -40 dB (casi silencioso). ) y 0dB (máx; en relación con el volumen de transmisión) en función de:

• Duración del efecto preestablecido (puede ser codificado o configurado por el usuario)
• Tiempo transcurrido desde que comenzó la reproducción

Vea computeVolume() continuación para los bits jugosos.

El código original completo se puede encontrar aquí: Google Source

private MediaPlayer mMediaPlayer;
private long mCrescendoDuration = 0;
private long mCrescendoStopTime = 0;

// Default settings
private static final boolean DEFAULT_CRESCENDO = true;
private static final int CRESCENDO_DURATION = 1;

// Internal message codes
private static final int EVENT_VOLUME = 3;


// Create a message Handler
@SuppressLint("HandlerLeak")
private Handler mHandler = new Handler() {
    @Override
    public void handleMessage(Message msg) {
        switch (msg.what) {
            ...

            case EVENT_VOLUME:
            if (adjustVolume()) {
                scheduleVolumeAdjustment();
            }
            break;

            ...
        }
    }
};


// Obtain user preferences
private void getPrefs() {
    SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
    ...

    final boolean crescendo = prefs.getBoolean(SettingsActivity.KEY_CRESCENDO, DEFAULT_CRESCENDO);
    if (crescendo) {
        // Convert mins to millis
        mCrescendoDuration = CRESCENDO_DURATION * 1000 * 60;
    } else {
        mCrescendoDuration = 0;
    }

    ...
}


// Start the playback
private void play(Alarm alarm) {
    ...

    // Check to see if we are already playing
    stop();

    // Obtain user preferences
    getPrefs();

    // Check if crescendo is enabled. If it is, set alarm volume to 0.
    if (mCrescendoDuration > 0) {
        mMediaPlayer.setVolume(0, 0);
    }

    mMediaPlayer.setDataSource(this, alarm.alert);
    startAlarm(mMediaPlayer);

    ...
}


// Do the common stuff when starting the alarm.
private void startAlarm(MediaPlayer player) throws java.io.IOException, IllegalArgumentException, IllegalStateException {

    final AudioManager audioManager = (AudioManager)getSystemService(Context.AUDIO_SERVICE);

    // Do not play alarms if stream volume is 0
    // (typically because ringer mode is silent).
    if (audioManager.getStreamVolume(AudioManager.STREAM_ALARM) != 0) {
        player.setAudioStreamType(AudioManager.STREAM_ALARM);
        player.setLooping(true);
        player.prepare();
        player.start();

        // Schedule volume adjustment
        if (mCrescendoDuration > 0) {
            mCrescendoStopTime = System.currentTimeMillis() + mCrescendoDuration;
            scheduleVolumeAdjustment();
        }
    }
}


// Stop the playback
public void stop() {
    ...

    if (mMediaPlayer != null) {
        mMediaPlayer.stop();
        mMediaPlayer.release();
        mMediaPlayer = null;
    }

    mCrescendoDuration = 0;
    mCrescendoStopTime = 0;

    ...
}


// Schedule volume adjustment 50ms in the future.
private void scheduleVolumeAdjustment() {
    // Ensure we never have more than one volume adjustment queued.
    mHandler.removeMessages(EVENT_VOLUME);
    // Queue the next volume adjustment.
    mHandler.sendMessageDelayed( mHandler.obtainMessage(EVENT_VOLUME, null), 50);
}


// Adjusts the volume of the ringtone being played to create a crescendo effect.
private boolean adjustVolume() {
    // If media player is absent or not playing, ignore volume adjustment.
    if (mMediaPlayer == null || !mMediaPlayer.isPlaying()) {
        mCrescendoDuration = 0;
        mCrescendoStopTime = 0;
        return false;
    }
    // If the crescendo is complete set the volume to the maximum; we''re done.
    final long currentTime = System.currentTimeMillis();
    if (currentTime > mCrescendoStopTime) {
        mCrescendoDuration = 0;
        mCrescendoStopTime = 0;
        mMediaPlayer.setVolume(1, 1);
        return false;
    }
    // The current volume of the crescendo is the percentage of the crescendo completed.
    final float volume = computeVolume(currentTime, mCrescendoStopTime, mCrescendoDuration);
    mMediaPlayer.setVolume(volume, volume);

    // Schedule the next volume bump in the crescendo.
    return true;
}


/**
 * @param currentTime current time of the device
 * @param stopTime time at which the crescendo finishes
 * @param duration length of time over which the crescendo occurs
 * @return the scalar volume value that produces a linear increase in volume (in decibels)
 */
private static float computeVolume(long currentTime, long stopTime, long duration) {
    // Compute the percentage of the crescendo that has completed.
    final float elapsedCrescendoTime = stopTime - currentTime;
    final float fractionComplete = 1 - (elapsedCrescendoTime / duration);
    // Use the fraction to compute a target decibel between -40dB (near silent) and 0dB (max).
    final float gain = (fractionComplete * 40) - 40;
    // Convert the target gain (in decibels) into the corresponding volume scalar.
    final float volume = (float) Math.pow(10f, gain/20f);
    //LOGGER.v("Ringtone crescendo %,.2f%% complete (scalar: %f, volume: %f dB)", fractionComplete * 100, volume, gain);
    return volume;
}

Answer 2

Es una clase muy buena sngreco.

Para hacerlo más completo, agregaré la función stop () para detener el reproductor con fade, y stopAndRelease () para detener al jugador y liberar los recursos de forma segura, muy útil para usar cuando llamas a métodos de actividad como onStop () o onDestroy () .

Los dos métodos:

    public void stop(int fadeDuration)
{
    try {
        // Set current volume, depending on fade or not
        if (fadeDuration > 0)
            iVolume = INT_VOLUME_MAX;
        else
            iVolume = INT_VOLUME_MIN;

        updateVolume(0);

        // Start increasing volume in increments
        if (fadeDuration > 0)
        {
            final Timer timer = new Timer(true);
            TimerTask timerTask = new TimerTask()
            {
                @Override
                public void run()
                {
                    updateVolume(-1);
                    if (iVolume == INT_VOLUME_MIN)
                    {
                        // Pause music
                        mediaPlayer.stop();
                        timer.cancel();
                        timer.purge();
                    }
                }
            };

            // calculate delay, cannot be zero, set to 1 if zero
            int delay = fadeDuration / INT_VOLUME_MAX;
            if (delay == 0)
                delay = 1;

            timer.schedule(timerTask, delay, delay);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }

}

public void stopAndRelease(int fadeDuration) {
    try {
        final Timer timer = new Timer(true);
        TimerTask timerTask = new TimerTask()
        {
            @Override
            public void run()
            {
                updateVolume(-1);
                if (iVolume == INT_VOLUME_MIN)
                {
                    // Stop and Release player after Pause music
                    mediaPlayer.stop();
                    mediaPlayer.release();
                    timer.cancel();
                    timer.purge();
                }
            }
        };

        timer.schedule(timerTask, fadeDuration);
    } catch (Exception e) {
        e.printStackTrace();
    }
}

Answer 3

Esta es toda mi clase de controlador para Android MediaPlayer. Mira las funciones play () y pause (). Ambos contienen la habilidad de desvanecerse o no. La función updateVolume () fue la clave para permitir que el sonido aumente / disminuya linealmente.

package com..utilities;

import java.io.File;
import java.util.Timer;
import java.util.TimerTask;

import android.content.Context;
import android.media.MediaPlayer;
import android.net.Uri;

public class MusicHandler {
    private MediaPlayer mediaPlayer;
    private Context context;
    private int iVolume;

    private final static int INT_VOLUME_MAX = 100;
    private final static int INT_VOLUME_MIN = 0;
    private final static float FLOAT_VOLUME_MAX = 1;
    private final static float FLOAT_VOLUME_MIN = 0;

    public MusicHandler(Context context) {
        this.context = context;
    }

    public void load(String path, boolean looping) {
        mediaPlayer = MediaPlayer.create(context, Uri.fromFile(new File(path)));
        mediaPlayer.setLooping(looping);
    }

    public void load(int address, boolean looping) {
        mediaPlayer = MediaPlayer.create(context, address);
        mediaPlayer.setLooping(looping);
    }

    public void play(int fadeDuration) {
        // Set current volume, depending on fade or not
        if (fadeDuration > 0)
            iVolume = INT_VOLUME_MIN;
        else
            iVolume = INT_VOLUME_MAX;

        updateVolume(0);

        // Play music
        if (!mediaPlayer.isPlaying())
            mediaPlayer.start();

        // Start increasing volume in increments
        if (fadeDuration > 0) {
            final Timer timer = new Timer(true);
            TimerTask timerTask = new TimerTask() {
                @Override
                public void run() {
                    updateVolume(1);
                    if (iVolume == INT_VOLUME_MAX) {
                        timer.cancel();
                        timer.purge();
                    }
                }
            };

            // calculate delay, cannot be zero, set to 1 if zero
            int delay = fadeDuration / INT_VOLUME_MAX;
            if (delay == 0)
                delay = 1;

            timer.schedule(timerTask, delay, delay);
        }
    }

    public void pause(int fadeDuration) {
        // Set current volume, depending on fade or not
        if (fadeDuration > 0)
            iVolume = INT_VOLUME_MAX;
        else
            iVolume = INT_VOLUME_MIN;

        updateVolume(0);

        // Start increasing volume in increments
        if (fadeDuration > 0) {
            final Timer timer = new Timer(true);
            TimerTask timerTask = new TimerTask() {
                @Override
                public void run() {
                    updateVolume(-1);
                    if (iVolume == INT_VOLUME_MIN) {
                        // Pause music
                        if (mediaPlayer.isPlaying())
                            mediaPlayer.pause();
                        timer.cancel();
                        timer.purge();
                    }
                }
            };

            // calculate delay, cannot be zero, set to 1 if zero
            int delay = fadeDuration / INT_VOLUME_MAX;
            if (delay == 0)
                delay = 1;

            timer.schedule(timerTask, delay, delay);
        }
    }

    private void updateVolume(int change) {
        // increment or decrement depending on type of fade
        iVolume = iVolume + change;

        // ensure iVolume within boundaries
        if (iVolume < INT_VOLUME_MIN)
            iVolume = INT_VOLUME_MIN;
        else if (iVolume > INT_VOLUME_MAX)
            iVolume = INT_VOLUME_MAX;

        // convert to float value
        float fVolume = 1 - ((float) Math.log(INT_VOLUME_MAX - iVolume) / (float) Math.log(INT_VOLUME_MAX));

        // ensure fVolume within boundaries
        if (fVolume < FLOAT_VOLUME_MIN)
            fVolume = FLOAT_VOLUME_MIN;
        else if (fVolume > FLOAT_VOLUME_MAX)
            fVolume = FLOAT_VOLUME_MAX;

        mediaPlayer.setVolume(fVolume, fVolume);
    }
}

Answer 4

He estado trabajando en esto, espero que ayude: D:

private static void crossFade() {
    MediaPlayerManager.fadeOut(currentPlayer, 2000);
    MediaPlayerManager.fadeIn(auxPlayer, 2000);
    currentPlayer = auxPlayer;
    auxPlayer = null;
}

public static void fadeOut(final MediaPlayer _player, final int duration) {
    final float deviceVolume = getDeviceVolume();
    final Handler h = new Handler();
    h.postDelayed(new Runnable() {
        private float time = duration;
        private float volume = 0.0f;

        @Override
        public void run() {
            if (!_player.isPlaying())
                _player.start();
            // can call h again after work!
            time -= 100;
            volume = (deviceVolume * time) / duration;
            _player.setVolume(volume, volume);
            if (time > 0)
                h.postDelayed(this, 100);
            else {
                _player.stop();
                _player.release();
            }
        }
    }, 100); // 1 second delay (takes millis)


}

public static void fadeIn(final MediaPlayer _player, final int duration) {
    final float deviceVolume = getDeviceVolume();
    final Handler h = new Handler();
    h.postDelayed(new Runnable() {
        private float time = 0.0f;
        private float volume = 0.0f;

        @Override
        public void run() {
            if (!_player.isPlaying())
                _player.start();
            // can call h again after work!
            time += 100;
            volume = (deviceVolume * time) / duration;
            _player.setVolume(volume, volume);
            if (time < duration)
                h.postDelayed(this, 100);
        }
    }, 100); // 1 second delay (takes millis)

}
public static float getDeviceVolume() {
    int volumeLevel = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
    int maxVolume = audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);

    return (float) volumeLevel / maxVolume;
}

Answer 5

Una forma de hacerlo es usar MediaPlayer.setVolume (derecha, izquierda) y hacer que estos valores disminuyan después de cada iteración ... aquí hay una idea aproximada

float volume = 1;
float speed = 0.05f;

public void FadeOut(float deltaTime)
{
    MediaPlayer.setVolume(volume, volume);
    volume -= speed* deltaTime

}
public void FadeIn(float deltaTime)
{
    MediaPlayer.setVolume(volume, volume);
    volume += speed* deltaTime

}

Se debe llamar a FadeIn o FadeOut una vez que haya expirado su temporizador, el método no necesita tomar deltaTime, pero es una buena práctica ya que bajará el volumen a la misma velocidad en todos los dispositivos.