forked from youpy/go-wav
/
writer.go
55 lines (47 loc) · 1.36 KB
/
writer.go
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package wav
import (
"encoding/binary"
riff "github.com/youpy/go-riff"
"io"
)
type Writer struct {
io.Writer
Format *WavFormat
}
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
}
func (w *Writer) WriteSamples(samples []Sample) (err error) {
bitsPerSample := w.Format.BitsPerSample
numChannels := w.Format.NumChannels
var i uint16
for _, sample := range samples {
if bitsPerSample == 16 {
for i = 0; i < numChannels; i++ {
err = binary.Write(w, binary.LittleEndian, int16(sample.Values[i]))
if err != nil {
return
}
}
} else {
for i = 0; i < numChannels; i++ {
binary.Write(w, binary.LittleEndian, int8(sample.Values[i]))
if err != nil {
return
}
}
}
}
return
}