public static WavFile newWavFile(
File file, int numChannels, long numFrames, int validBits, long sampleRate)
throws IOException, WavFileException {
// Instantiate new Wavfile and initialise
final WavFile wavFile = new WavFile();
wavFile.file = file;
wavFile.numChannels = numChannels;
wavFile.numFrames = numFrames;
wavFile.sampleRate = sampleRate;
wavFile.bytesPerSample = (validBits + 7) / 8;
wavFile.blockAlign = wavFile.bytesPerSample * numChannels;
wavFile.validBits = validBits;
// Sanity check arguments
if ((numChannels < 1) || (numChannels > 65535)) {
throw new WavFileException("Illegal number of channels, valid range 1 to 65536");
}
if (numFrames < 0) {
throw new WavFileException("Number of frames must be positive");
}
if ((validBits < 2) || (validBits > 65535)) {
throw new WavFileException("Illegal number of valid bits, valid range 2 to 65536");
}
if (sampleRate < 0) {
throw new WavFileException("Sample rate must be positive");
}
// Create output stream for writing data
wavFile.oStream = new FileOutputStream(file);
// Calculate the chunk sizes
final long dataChunkSize = wavFile.blockAlign * numFrames;
long mainChunkSize =
4
+ // Riff Type
8
+ // Format ID and size
16
+ // Format data
8
+ // Data ID and size
dataChunkSize;
// Chunks must be word aligned, so if odd number of audio data bytes
// adjust the main chunk size
if ((dataChunkSize % 2) == 1) {
mainChunkSize += 1;
wavFile.wordAlignAdjust = true;
} else {
wavFile.wordAlignAdjust = false;
}
// Set the main chunk size
putLE(RIFF_CHUNK_ID, wavFile.buffer, 0, 4);
putLE(mainChunkSize, wavFile.buffer, 4, 4);
putLE(RIFF_TYPE_ID, wavFile.buffer, 8, 4);
// Write out the header
wavFile.oStream.write(wavFile.buffer, 0, 12);
// Put format data in buffer
final long averageBytesPerSecond = sampleRate * wavFile.blockAlign;
putLE(FMT_CHUNK_ID, wavFile.buffer, 0, 4); // Chunk ID
putLE(16, wavFile.buffer, 4, 4); // Chunk Data Size
putLE(1, wavFile.buffer, 8, 2); // Compression Code (Uncompressed)
putLE(numChannels, wavFile.buffer, 10, 2); // Number of channels
putLE(sampleRate, wavFile.buffer, 12, 4); // Sample Rate
putLE(averageBytesPerSecond, wavFile.buffer, 16, 4); // Average Bytes Per Second
putLE(wavFile.blockAlign, wavFile.buffer, 20, 2); // Block Align
putLE(validBits, wavFile.buffer, 22, 2); // Valid Bits
// Write Format Chunk
wavFile.oStream.write(wavFile.buffer, 0, 24);
// Start Data Chunk
putLE(DATA_CHUNK_ID, wavFile.buffer, 0, 4); // Chunk ID
putLE(dataChunkSize, wavFile.buffer, 4, 4); // Chunk Data Size
// Write Format Chunk
wavFile.oStream.write(wavFile.buffer, 0, 8);
// Calculate the scaling factor for converting to a normalised double
if (wavFile.validBits > 8) {
// If more than 8 validBits, data is signed
// Conversion required multiplying by magnitude of max positive value
wavFile.floatOffset = 0;
wavFile.floatScale = Long.MAX_VALUE >> (64 - wavFile.validBits);
} else {
// Else if 8 or less validBits, data is unsigned
// Conversion required dividing by max positive value
wavFile.floatOffset = 1;
wavFile.floatScale = 0.5 * ((1 << wavFile.validBits) - 1);
}
// Finally, set the IO State
wavFile.bufferPointer = 0;
wavFile.bytesRead = 0;
wavFile.frameCounter = 0;
wavFile.ioState = IOState.WRITING;
return wavFile;
}
