Java:Master Gain 不支持异常

Question

在 Linux 中此代码不起作用:我添加了两行

// Added two lines.
DataLine.Info info = new DataLine.Info( SourceDataLine.class, audioFormat );
SourceDataLine dataLine = (SourceDataLine) AudioSystem.getLine( info );
// Adjust the volume on the output line.
if( dataLine.isControlSupported( FloatControl.Type.MASTER_GAIN)) {
    // If inside this if, the Master_Gain must be supported. Yes?
    FloatControl volume = (FloatControl) dataLine.getControl(FloatControl.Type.MASTER_GAIN);
    // This line throws an exception. "Master_Gain not supported"
    volume.setValue( 100.0F );
}

这正常吗？我必须做什么才能解决这个问题？
在Windows中它可以工作。

谢谢马丁。

Answer 1

您能否在尝试使用控件之前尝试open() 该行。像这样的事情:

// Added two lines.
DataLine.Info info = new DataLine.Info( SourceDataLine.class, audioFormat );
SourceDataLine dataLine = (SourceDataLine) AudioSystem.getLine( info );
dataLine.open();
// Adjust the volume on the output line.
if( dataLine.isControlSupported( FloatControl.Type.MASTER_GAIN)) {
    // If inside this if, the Master_Gain must be supported. Yes?
    FloatControl volume = (FloatControl) dataLine.getControl(FloatControl.Type.MASTER_GAIN);
    // This line throws an exception. "Master_Gain not supported"
    volume.setValue( 100.0F );
}