File	Doc	Category	Size	Date	Package
WaveHeader.java	API Doc	Android 1.5 API	8731	Wed May 06 22:41:56 BST 2009	android.speech.srec

WaveHeader

• java.lang.Object

Fields Summary
private static final String	TAG
private static final int	HEADER_LENGTH
public static final short	FORMAT_PCM Indicates PCM format.
public static final short	FORMAT_ALAW Indicates ALAW format.
public static final short	FORMAT_ULAW Indicates ULAW format.
private short	mFormat
private short	mNumChannels
private int	mSampleRate
private short	mBitsPerSample
private int	mNumBytes

Constructors Summary
public WaveHeader() Construct a WaveHeader, with all fields defaulting to zero.
public WaveHeader(short format, short numChannels, int sampleRate, short bitsPerSample, int numBytes) Construct a WaveHeader, with fields initialized. param format format of audio data, one of {@link #FORMAT_PCM}, {@link #FORMAT_ULAW}, or {@link #FORMAT_ALAW}. param numChannels 1 for mono, 2 for stereo. param sampleRate typically 8000, 11025, 16000, 22050, or 44100 hz. param bitsPerSample usually 16 for PCM, 8 for ULAW or 8 for ALAW. param numBytes size of audio data after this header, in bytes. mFormat = format; mSampleRate = sampleRate; mNumChannels = numChannels; mBitsPerSample = bitsPerSample; mNumBytes = numBytes;

Methods Summary
public short	getBitsPerSample() Get the number of bits per sample. return number of bits per sample, usually 16 for PCM, 8 for ULAW or 8 for ALAW. return mBitsPerSample;
public short	getFormat() Get the format field. return format field, one of {@link #FORMAT_PCM}, {@link #FORMAT_ULAW}, or {@link #FORMAT_ALAW}. return mFormat;
public int	getNumBytes() Get the size of audio data after this header, in bytes. return size of audio data after this header, in bytes. return mNumBytes;
public short	getNumChannels() Get the number of channels. return number of channels, 1 for mono, 2 for stereo. return mNumChannels;
public int	getSampleRate() Get the sample rate. return sample rate, typically 8000, 11025, 16000, 22050, or 44100 hz. return mSampleRate;
public int	read(java.io.InputStream in) Read and initialize a WaveHeader. param in {@link java.io.InputStream} to read from. return number of bytes consumed. throws IOException /* RIFF header */ readId(in, "RIFF"); int numBytes = readInt(in) - 36; readId(in, "WAVE"); /* fmt chunk */ readId(in, "fmt "); if (16 != readInt(in)) throw new IOException("fmt chunk length not 16"); mFormat = readShort(in); mNumChannels = readShort(in); mSampleRate = readInt(in); int byteRate = readInt(in); short blockAlign = readShort(in); mBitsPerSample = readShort(in); if (byteRate != mNumChannels * mSampleRate * mBitsPerSample / 8) { throw new IOException("fmt.ByteRate field inconsistent"); } if (blockAlign != mNumChannels * mBitsPerSample / 8) { throw new IOException("fmt.BlockAlign field inconsistent"); } /* data chunk */ readId(in, "data"); mNumBytes = readInt(in); return HEADER_LENGTH;
private static void	readId(java.io.InputStream in, java.lang.String id) for (int i = 0; i < id.length(); i++) { if (id.charAt(i) != in.read()) throw new IOException( id + " tag not present"); }
private static int	readInt(java.io.InputStream in) return in.read() | (in.read() << 8) | (in.read() << 16) | (in.read() << 24);
private static short	readShort(java.io.InputStream in) return (short)(in.read() | (in.read() << 8));
public android.speech.srec.WaveHeader	setBitsPerSample(short bitsPerSample) Set the number of bits per sample. param bitsPerSample number of bits per sample, usually 16 for PCM, 8 for ULAW or 8 for ALAW. return reference to this WaveHeader instance. mBitsPerSample = bitsPerSample; return this;
public android.speech.srec.WaveHeader	setFormat(short format) Set the format field. param format one of {@link #FORMAT_PCM}, {@link #FORMAT_ULAW}, or {@link #FORMAT_ALAW}. return reference to this WaveHeader instance. mFormat = format; return this;
public android.speech.srec.WaveHeader	setNumBytes(int numBytes) Set the size of audio data after this header, in bytes. param numBytes size of audio data after this header, in bytes. return reference to this WaveHeader instance. mNumBytes = numBytes; return this;
public android.speech.srec.WaveHeader	setNumChannels(short numChannels) Set the number of channels. param numChannels 1 for mono, 2 for stereo. return reference to this WaveHeader instance. mNumChannels = numChannels; return this;
public android.speech.srec.WaveHeader	setSampleRate(int sampleRate) Set the sample rate. param sampleRate sample rate, typically 8000, 11025, 16000, 22050, or 44100 hz. return reference to this WaveHeader instance. mSampleRate = sampleRate; return this;
public java.lang.String	toString() return String.format( "WaveHeader format=%d numChannels=%d sampleRate=%d bitsPerSample=%d numBytes=%d", mFormat, mNumChannels, mSampleRate, mBitsPerSample, mNumBytes);
public int	write(java.io.OutputStream out) Write a WAVE file header. param out {@link java.io.OutputStream} to receive the header. return number of bytes written. throws IOException /* RIFF header */ writeId(out, "RIFF"); writeInt(out, 36 + mNumBytes); writeId(out, "WAVE"); /* fmt chunk */ writeId(out, "fmt "); writeInt(out, 16); writeShort(out, mFormat); writeShort(out, mNumChannels); writeInt(out, mSampleRate); writeInt(out, mNumChannels * mSampleRate * mBitsPerSample / 8); writeShort(out, (short)(mNumChannels * mBitsPerSample / 8)); writeShort(out, mBitsPerSample); /* data chunk */ writeId(out, "data"); writeInt(out, mNumBytes); return HEADER_LENGTH;
private static void	writeId(java.io.OutputStream out, java.lang.String id) for (int i = 0; i < id.length(); i++) out.write(id.charAt(i));
private static void	writeInt(java.io.OutputStream out, int val) out.write(val >> 0); out.write(val >> 8); out.write(val >> 16); out.write(val >> 24);
private static void	writeShort(java.io.OutputStream out, short val) out.write(val >> 0); out.write(val >> 8);