使用JLayer时在Java中更改卷

Question

我正在使用JLayer播放来自互联网的mp3数据输入流.如何更改输出的音量？

我正在使用此代码来播放它:

URL u = new URL(s);
URLConnection conn = u.openConnection();  
conn.setConnectTimeout(Searcher.timeoutms);  
conn.setReadTimeout(Searcher.timeoutms);

bitstream = new Bitstream(conn.getInputStream()/*new FileInputStream(quick_file)*/);
System.out.println(bitstream);
decoder = new Decoder();
decoder.setEqualizer(equalizer);
audio = FactoryRegistry.systemRegistry().createAudioDevice();
audio.open(decoder);
for(int i = quick_positions[0]; i > 0; i--){
    Header h = bitstream.readFrame();
    if (h == null){
        return;
    }
bitstream.closeFrame();

Answer 1

您可能会认为这是一个不可接受的黑客,但它在我写的MP3播放器中有效.它需要为其中一个JLayer类添加一个小代码.

将以下方法添加到javazoom.jl.player.JavaSoundAudioDevice.

public void setLineGain(float gain)
{
    if (source != null)
    {
        FloatControl volControl = (FloatControl) source.getControl(FloatControl.Type.MASTER_GAIN);
        float newGain = Math.min(Math.max(gain, volControl.getMinimum()), volControl.getMaximum());

        volControl.setValue(newGain);
    }
}

然后,这个新方法允许您使用这样的代码更改卷.

if (audio instanceof JavaSoundAudioDevice)
{
    JavaSoundAudioDevice jsAudio = (JavaSoundAudioDevice) audio;
    jsAudio.setLineGain(yourGainGoesHere);
}

Answer 2

尝试调整均衡器的所有频段以获得您\xe2\x80\x99 想要获得的音量。也许你也可以使用EQFunction来实现这一点？

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public class ChangeVolumeFunction extends EQFunction {\n    public double volume = 1.0;\n    public void setVolume(double volume) { this.volume = volume; }\n    public float getBand(int band) { return (float) (Math.log(volume) / Math.log(2) * 6.0); }\n}\n

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