azure tts use go sdk generate in stream to wav less 46 byte - azure

Question

i use this samplehttps://github.com/Microsoft/cognitive-services-speech-sdk-go/blob/1af83b0cf8fb/samples/synthesizer/to_audio_data_stream.go
and i wirte byte to file and i find file cant open
stream.SaveToWavFileAsync("fun.wav")
//use this func can save a file which can open
output
Synthesis started.
Synthesizing, audio chunk size 65582.
Synthesizing, audio chunk size 294510.
Synthesizing, audio chunk size 56446.
Synthesizing, audio chunk size 65582.
Synthesizing, audio chunk size 1710.
Synthesized, audio length 483646.
Read [483600] bytes from audio data stream.
the stream less 46 bytes

Answer 1

pcm need add wav head.
func PcmToWav(dst []byte, numChannel int, sampleRate int) (resDst []byte) {
byteDst := dst
longSampleRate := sampleRate
byteRate := 16 * sampleRate * numChannel / 8
totalAudioLen := len(byteDst)
totalDataLen := totalAudioLen + 36
var header = make([]byte, 44)
// RIFF/WAVE header
header[0] = 'R'
header[1] = 'I'
header[2] = 'F'
header[3] = 'F'
header[4] = byte(totalDataLen & 0xff)
header[5] = byte((totalDataLen >> 8) & 0xff)
header[6] = byte((totalDataLen >> 16) & 0xff)
header[7] = byte((totalDataLen >> 24) & 0xff)
//WAVE
header[8] = 'W'
header[9] = 'A'
header[10] = 'V'
header[11] = 'E'
// 'fmt ' chunk
header[12] = 'f'
header[13] = 'm'
header[14] = 't'
header[15] = ' '
// 4 bytes: size of 'fmt ' chunk
header[16] = 16
header[17] = 0
header[18] = 0
header[19] = 0
// format = 1
header[20] = 1
header[21] = 0
header[22] = byte(numChannel)
header[23] = 0
header[24] = byte(longSampleRate & 0xff)
header[25] = byte((longSampleRate >> 8) & 0xff)
header[26] = byte((longSampleRate >> 16) & 0xff)
header[27] = byte((longSampleRate >> 24) & 0xff)
header[28] = byte(byteRate & 0xff)
header[29] = byte((byteRate >> 8) & 0xff)
header[30] = byte((byteRate >> 16) & 0xff)
header[31] = byte((byteRate >> 24) & 0xff)
// block align
header[32] = byte(2 * 16 / 8)
header[33] = 0
// bits per sample
header[34] = 16
header[35] = 0
//data
header[36] = 'd'
header[37] = 'a'
header[38] = 't'
header[39] = 'a'
header[40] = byte(totalAudioLen & 0xff)
header[41] = byte((totalAudioLen >> 8) & 0xff)
header[42] = byte((totalAudioLen >> 16) & 0xff)
header[43] = byte((totalAudioLen >> 24) & 0xff)
resDst = append(header, dst...)
return
}