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;
}
public static WavFile openWavFile(File file) throws IOException, WavFileException {
// Instantiate new Wavfile and store the file reference
final WavFile wavFile = new WavFile();
wavFile.file = file;
// Create a new file input stream for reading file data
wavFile.iStream = new FileInputStream(file);
// Read the first 12 bytes of the file
int bytesRead = wavFile.iStream.read(wavFile.buffer, 0, 12);
if (bytesRead != 12) {
throw new WavFileException("Not enough wav file bytes for header");
}
// Extract parts from the header
final long riffChunkID = getLE(wavFile.buffer, 0, 4);
long chunkSize = getLE(wavFile.buffer, 4, 4);
final long riffTypeID = getLE(wavFile.buffer, 8, 4);
// Check the header bytes contains the correct signature
if (riffChunkID != RIFF_CHUNK_ID) {
throw new WavFileException("Invalid Wav Header data, incorrect riff chunk ID");
}
if (riffTypeID != RIFF_TYPE_ID) {
throw new WavFileException("Invalid Wav Header data, incorrect riff type ID");
}
// Check that the file size matches the number of bytes listed in header
if (file.length() != (chunkSize + 8)) {
throw new WavFileException(
"Header chunk size (" + chunkSize + ") does not match file size (" + file.length() + ")");
}
boolean foundFormat = false;
boolean foundData = false;
// Search for the Format and Data Chunks
while (true) {
// Read the first 8 bytes of the chunk (ID and chunk size)
bytesRead = wavFile.iStream.read(wavFile.buffer, 0, 8);
if (bytesRead == -1) {
throw new WavFileException("Reached end of file without finding format chunk");
}
if (bytesRead != 8) {
throw new WavFileException("Could not read chunk header");
}
// Extract the chunk ID and Size
final long chunkID = getLE(wavFile.buffer, 0, 4);
chunkSize = getLE(wavFile.buffer, 4, 4);
// Word align the chunk size
// chunkSize specifies the number of bytes holding data. However,
// the data should be word aligned (2 bytes) so we need to calculate
// the actual number of bytes in the chunk
long numChunkBytes = ((chunkSize % 2) == 1) ? chunkSize + 1 : chunkSize;
if (chunkID == FMT_CHUNK_ID) {
// Flag that the format chunk has been found
foundFormat = true;
// Read in the header info
bytesRead = wavFile.iStream.read(wavFile.buffer, 0, 16);
// Check this is uncompressed data
final int compressionCode = (int) getLE(wavFile.buffer, 0, 2);
if (compressionCode != 1) {
throw new WavFileException("Compression Code " + compressionCode + " not supported");
}
// Extract the format information
wavFile.numChannels = (int) getLE(wavFile.buffer, 2, 2);
wavFile.sampleRate = getLE(wavFile.buffer, 4, 4);
wavFile.blockAlign = (int) getLE(wavFile.buffer, 12, 2);
wavFile.validBits = (int) getLE(wavFile.buffer, 14, 2);
if (wavFile.numChannels == 0) {
throw new WavFileException("Number of channels specified in header is equal to zero");
}
if (wavFile.blockAlign == 0) {
throw new WavFileException("Block Align specified in header is equal to zero");
}
if (wavFile.validBits < 2) {
throw new WavFileException("Valid Bits specified in header is less than 2");
}
if (wavFile.validBits > 64) {
throw new WavFileException(
"Valid Bits specified in header is greater than 64, this is greater than a long can hold");
}
// Calculate the number of bytes required to hold 1 sample
wavFile.bytesPerSample = (wavFile.validBits + 7) / 8;
if ((wavFile.bytesPerSample * wavFile.numChannels) != wavFile.blockAlign) {
throw new WavFileException(
"Block Align does not agree with bytes required for validBits and number of channels");
}
// Account for number of format bytes and then skip over
// any extra format bytes
numChunkBytes -= 16;
if (numChunkBytes > 0) {
wavFile.iStream.skip(numChunkBytes);
}
} else if (chunkID == DATA_CHUNK_ID) {
// Check if we've found the format chunk,
// If not, throw an exception as we need the format information
// before we can read the data chunk
if (foundFormat == false) {
throw new WavFileException("Data chunk found before Format chunk");
}
// Check that the chunkSize (wav data length) is a multiple of the
// block align (bytes per frame)
if ((chunkSize % wavFile.blockAlign) != 0) {
throw new WavFileException("Data Chunk size is not multiple of Block Align");
}
// Calculate the number of frames
wavFile.numFrames = chunkSize / wavFile.blockAlign;
// Flag that we've found the wave data chunk
foundData = true;
break;
} else {
// If an unknown chunk ID is found, just skip over the chunk data
wavFile.iStream.skip(numChunkBytes);
}
}
// Throw an exception if no data chunk has been found
if (foundData == false) {
throw new WavFileException("Did not find a data chunk");
}
// Calculate the scaling factor for converting to a normalised double
if (wavFile.validBits > 8) {
// If more than 8 validBits, data is signed
// Conversion required dividing by magnitude of max negative value
wavFile.floatOffset = 0;
wavFile.floatScale = 1 << (wavFile.validBits - 1);
} 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);
}
wavFile.bufferPointer = 0;
wavFile.bytesRead = 0;
wavFile.frameCounter = 0;
wavFile.ioState = IOState.READING;
return wavFile;
}