哦,您想找到音量吗?好吧,并非所有硬件都支持它,但以下是获取数据线的方法。
public static SourceDataLine getSourceDataLine(Line.Info lineInfo){
try{
return (SourceDataLine) AudioSystem.getLine(lineInfo);
}
catch(Exception ex){
ex.printStackTrace();
return null;
}
}
然后只需调用 SourceDataLine.getLevel() 即可获取音量。我希望这有帮助。
注意:如果声音来自 JVM 外部或者不是通过 JavaSound API,则此方法将不会检测到声音,因为 JVM 无法访问与 SourceDataLine 等效的操作系统。
更新:经过进一步研究,大多数系统上都没有实现 getLevel()。所以我根据这个论坛讨论手动实现了该方法:https://community.oracle.com/message/5391003 https://community.oracle.com/message/5391003
以下是课程:
public class Main {
public static void main(String[] args){
MicrophoneAnalyzer mic = new MicrophoneAnalyzer(FLACFileWriter.FLAC);
System.out.println("HELLO");
mic.open();
while(true){
byte[] buffer = new byte[mic.getTargetDataLine().getFormat().getFrameSize()];
mic.getTargetDataLine().read(buffer, 0, buffer.length);
try{
System.out.println(getLevel(mic.getAudioFormat(), buffer));
}
catch(Exception e){
System.out.println("ERROR");
e.printStackTrace();
}
}
}
public static double getLevel(AudioFormat af, byte[] chunk) throws IOException{
PCMSigned8Bit converter = new PCMSigned8Bit(af);
if(chunk.length != converter.getRequiredChunkByteSize())
return -1;
AudioInputStream ais = converter.convert(chunk);
ais.read(chunk, 0, chunk.length);
long lSum = 0;
for(int i=0; i<chunk.length; i++)
lSum = lSum + chunk[i];
double dAvg = lSum / chunk.length;
double sumMeanSquare = 0d;
for(int j=0; j<chunk.length; j++)
sumMeanSquare = sumMeanSquare + Math.pow(chunk[j] - dAvg, 2d);
double averageMeanSquare = sumMeanSquare / chunk.length;
return (Math.pow(averageMeanSquare,0.5d));
}
}
我使用的方法仅适用于 8bitPCM,因此我们必须将编码转换为使用这两个类的编码。这是通用的抽象转换器类。
import java.io.ByteArrayInputStream;
import java.io.IOException;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
import javax.sound.sampled.AudioSystem;
abstract class AbstractSignedLevelConverter
{
private AudioFormat srcf;
public AbstractSignedLevelConverter(AudioFormat sourceFormat)
{
srcf = sourceFormat;
}
protected AudioInputStream convert(byte[] chunk)
{
AudioInputStream ais = null;
if(AudioSystem.isConversionSupported( AudioFormat.Encoding.PCM_SIGNED,
srcf))
{
if(srcf.getEncoding() != AudioFormat.Encoding.PCM_SIGNED)
ais = AudioSystem.getAudioInputStream(
AudioFormat.Encoding.PCM_SIGNED,
new AudioInputStream(new ByteArrayInputStream(chunk),
srcf,
chunk.length * srcf.getFrameSize()));
else
ais = new AudioInputStream(new ByteArrayInputStream(chunk),
srcf,
chunk.length * srcf.getFrameSize());
}
return ais;
}
abstract public double convertToLevel(byte[] chunk) throws IOException;
public int getRequiredChunkByteSize()
{
return srcf.getFrameSize();
}
}
这是 8BitPCM 的
import java.io.IOException;
import javax.sound.sampled.AudioFormat;
import javax.sound.sampled.AudioInputStream;
public class PCMSigned8Bit extends AbstractSignedLevelConverter
{
PCMSigned8Bit(AudioFormat sourceFormat)
{
super(sourceFormat);
}
public double convertToLevel(byte[] chunk) throws IOException
{
if(chunk.length != getRequiredChunkByteSize())
return -1;
AudioInputStream ais = convert(chunk);
ais.read(chunk, 0, chunk.length);
return (double)chunk[0];
}
}
这是针对 TargetDataLine 的,它可能不适用于您的用例,但您可以围绕 SourceDataLine 构建一个包装器,并使用它来正确实现这些方法。希望这有帮助。