转换音频格式
我在转换WAV文件的音频格式时遇到了麻烦。
我正从麦克风录制声音，声音按以下格式录制：PCM_SIGNED 44100.0 Hz，16位，单声道，2字节/帧
我想将上述格式转换为ULAW 8000.0 Hz，8位，单声道，1字节/帧
我使用以下代码，
InputStream is = request.getInputStream(); AudioInputStream ais = AudioSystem.getAudioInputStream(is); AudioFormat oldFormat = ais.getFormat(); AudioFormat newFormat = new AudioFormat(AudioFormat.Encoding.ULAW, 8000, 8, 1, 1, 8000, false) ; AudioInputStream lowResAIS = AudioSystem.getAudioInputStream(newFormat, ais); //Getting the below Exception on this line 我收到以下错误，
java.lang.IllegalArgumentException：不支持的转换：ULAW 8000.0 Hz，8位，单声道，1字节/帧，来自PCM_SIGNED 44100.0 Hz，16位，单声道，2字节/帧，little-endian
有人可以帮我解决这个问题！
万分感谢！！！
你看过文档了吗？
抛出 ：IllegalArgumentException – 如果不支持转换#see #getTargetEncodings（AudioFormat）
并非每个系统都安装了足够的编解码器来转换为您要求的特定格式。 你假设你的确如此，但它抛出了exception，因为它无法转换为那种格式。
您可以使用getTargetEncodings以编程方式检查给定格式的适用性，而不依赖于exception，然后如果您不希望输出格式可用，则可以采取适当的操作（例如，回退到另一个，向用户显示此反馈是不可能的等等）。
这堂课可以帮到你。 我在这里找到了 ：
package uk.co.mmscomputing.sound; import java.io.*; public class CompressInputStream extends FilterInputStream{ /* Convert mono PCM byte stream into A-Law u-Law byte stream static AudioFormat alawformat= new AudioFormat(AudioFormat.Encoding.ALAW,8000,8,1,1,8000,false); static AudioFormat ulawformat= new AudioFormat(AudioFormat.Encoding.ULAW,8000,8,1,1,8000,false); PCM 8000.0 Hz, 16 bit, mono, SIGNED, little-endian static AudioFormat pcmformat = new AudioFormat(8000,16,1,true,false); */ static private Compressor alawcompressor=new ALawCompressor(); static private Compressor ulawcompressor=new uLawCompressor(); private Compressor compressor=null; public CompressInputStream(InputStream in, boolean useALaw)throws IOException{ super(in); compressor=(useALaw)?alawcompressor:ulawcompressor; } public int read()throws IOException{ throw new IOException(getClass().getName()+".read() :\n\tDo not support simple read()."); } public int read(byte[] b)throws IOException{ return read(b,0,b.length); } public int read(byte[] b, int off, int len)throws IOException{ int i,sample; byte[] inb; inb=new byte[len<<1]; // get 16bit PCM data len=in.read(inb); if(len==-1){return -1;}; i=0; while(i>1; } } abstract class Compressor{ protected abstract int compress(short sample); } /* Mathematical Tools in Signal Processing with C++ and Java Simulations by Willi-Hans Steeb International School for Scientific Computing */ class ALawCompressor extends Compressor{ static final int cClip = 32635; static final int[] ALawCompressTable ={ 1,1,2,2,3,3,3,3, 4,4,4,4,4,4,4,4, 5,5,5,5,5,5,5,5, 5,5,5,5,5,5,5,5, 6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7 }; protected int compress(short sample){ int sign; int exponent; int mantissa; int compressedByte; sign = ((~sample) >> 8) & 0x80; if(sign==0){ sample *= -1;} if(sample > cClip){ sample = cClip; } if(sample >= 256){ exponent = ALawCompressTable[(sample >> 8) & 0x007F]; mantissa = (sample >> (exponent + 3) ) & 0x0F; compressedByte = 0x007F & ((exponent << 4) | mantissa); }else{ compressedByte = 0x007F & (sample >> 4); } compressedByte ^= (sign ^ 0x55); return compressedByte; } } class uLawCompressor extends Compressor{ static final int cClip = 32635; static final int cBias = 0x84; int[] uLawCompressTable ={ 0,0,1,1,2,2,2,2,3,3,3,3,3,3,3,3, 4,4,4,4,4,4,4,4,4,4,4,4,4,4,4,4, 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7, 7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7 }; protected int compress(short sample){ int sign; int exponent; int mantissa; int compressedByte; sign = (sample >> 8) & 0x80; if(sign!=0){ sample *= -1;} if(sample > cClip){ sample = cClip; } sample += cBias; exponent = uLawCompressTable[(sample >> 7) & 0x00FF]; mantissa = (sample >> (exponent + 3)) & 0x0F; compressedByte = ~(sign | (exponent << 4) | mantissa); return compressedByte&0x000000FF; } }