func NewWriter(w io.Writer, format Format, length time.Duration) (writer *Writer) {
dataSize := uint32(float64(length/time.Second)*float64(format.SampleRate)) * uint32(format.BlockAlign)
riffSize := 4 + 8 + 16 + 8 + dataSize
riffWriter := riff.NewWriter(w, []byte("WAVE"), riffSize)
writer = &Writer{riffWriter, &format}
riffWriter.WriteChunk([]byte("fmt "), 16, func(w io.Writer) {
binary.Write(w, binary.LittleEndian, format)
})
riffWriter.WriteChunk([]byte("data"), dataSize, func(w io.Writer) {})
return writer
}
func NewWriter(w io.Writer, numSamples uint32, numChannels uint16, sampleRate uint32, bitsPerSample uint16) (writer *Writer) {
blockAlign := numChannels * bitsPerSample / 8
byteRate := sampleRate * uint32(blockAlign)
format := &WavFormat{AudioFormatPCM, numChannels, sampleRate, byteRate, blockAlign, bitsPerSample}
dataSize := numSamples * uint32(format.BlockAlign)
riffSize := 4 + 8 + 16 + 8 + dataSize
riffWriter := riff.NewWriter(w, []byte("WAVE"), riffSize)
writer = &Writer{riffWriter, format}
riffWriter.WriteChunk([]byte("fmt "), 16, func(w io.Writer) {
binary.Write(w, binary.LittleEndian, format)
})
riffWriter.WriteChunk([]byte("data"), dataSize, func(w io.Writer) {})
return writer
}