dsp/audio/wav.go

package audio

import (
	"bytes"
	"encoding/binary"
	"errors"
	"fmt"
	"io"
	"math"
	"os"
	"path/filepath"

)

/*
-----RIFF-----
RIFF			4	标头字母
CHUNK_SIZE		4	整个RIFF文件的长度(不包含RIFF和CHUNK_SIZE这两个字段的长度)
FORMAT			4	格式,WAVE代表是wav文件,WAVE格式要求带有标头为fmt和data的子chunk
-----FMT -----
SUB_CHUNK_ID	4	子chunk的标头字母,此处为"fmt "(注意,fmt后面是带一个空格的),其相当于wav的属性字段
SUB_CHUNK_SIZE	4	此subchunk的长度(不包含SUB_CHUNK_ID和SUB_CHUNK_SIZE两个字段的长度)
AUDIO_FORMAT	2	音频格式,pcm为1
NUM_CHANNELS	2	声道数量,理论上可以n声道,一般我们用单声道mono,或者双声道stereo(双声道也叫立体声)
SAMPLE_RATE		4	采样率,每秒采样多少次,通常都有固定的采样选择(8000, 11025,12000,16000,22050,24000,32000,44100,48000)
BYTE_RATE		4	码率,即每秒播放多少byte数据,计算公式=SAMPLE_RATE*NUM_CHANNELS*BITS_PER_SAMPLE/8(不明白为何需要这个字段)
BLOCK_ALIGN		2	块对其,其值=BITS_PER_SAMPLE*NUM_CHANNELS/8
BITS_PER_SAMPLE 2	每个采样多少bit,通常为8,16,32(为8时候代表的是uint8,16代表的是int16,32代表float32)
-----DATA-----
SUB_CHUNK_ID	4	子chunk的标头字母,此处为"data"
SUB_CHUNK_SIZE	4	此subchunk的长度(不包含SUB_CHUNK_ID和SUB_CHUNK_SIZE两个字段的长度)
DATA				pcm的数据
-------------
*/

//MaxChannelNum 最大声道数量(此处只允许2）
const MaxChannelNum = 2

const (
	LeftChannel = 0
	RightChannel =1
)

//tag tag定义
type tag [4]byte

//一些变量
var (
	tagRIFF = tag{'R', 'I', 'F', 'F'} // "RIFF"
	tagWAVE = tag{'W', 'A', 'V', 'E'} // "WAVE"
	tagFmt  = tag{'f', 'm', 't', ' '} // "fmt "
	tagData = tag{'d', 'a', 't', 'a'} // "data"
)

//WavHeaderType wav子部头结构
type WavHeaderType struct {
	ID   tag
	Size uint32
}

//String 打印
func (wavHeader *WavHeaderType) String() string {
	return fmt.Sprintf("ID=%s,Size=%d", string(wavHeader.ID[:]), wavHeader.Size)
}

//头部size
var (
	sizeHeader = binary.Size(WavHeaderType{})
)

//chunkLoc ...
type chunkLoc struct {
	pos  int64
	size int64
}

//RiffType ...
type RiffType struct {
	WavHeaderType
	Fmt tag
}

//String ...
func (riff *RiffType) String() string {
	return fmt.Sprintf("ID=%s,Size=%d,Fmt=%s", string(riff.ID[:]), riff.Size, string(riff.Fmt[:]))
}

//WavFmtType wav格式结构（头部）
type WavFmtType struct {
	WavHeaderType
	AudioFormat   uint16
	Channels      uint16
	SampleRate    uint32
	BytesPerSec   uint32
	BytesPerBlock uint16
	BitsPerSample uint16
}

//String ...
func (wavFmt *WavFmtType) String() string {
	return fmt.Sprintf(
		"ID=%s,Size=%d,AudioFormat=%d,Channels=%d,SampleRate=%d,BytesPerSec=%d,BytesPerBlock=%d,BitsPerSample=%d",
		string(wavFmt.ID[:]), wavFmt.Size, wavFmt.AudioFormat, wavFmt.Channels, wavFmt.SampleRate,
		wavFmt.BytesPerSec, wavFmt.BytesPerBlock, wavFmt.BitsPerSample)
}

//SampleType 采样结构
type SampleType struct {
	val8s  [MaxChannelNum]uint8
	val16s [MaxChannelNum]int16
	val32s [MaxChannelNum]float32
}

//WavDataType wav整体结构（头部+采样数据结构）
type WavDataType struct {
	WavHeaderType
	Sample []SampleType
}

//String ...
func (wavData *WavDataType) String() string {
	blockNum := len(wavData.Sample)
	return fmt.Sprintf("ID=%s,Size=%d,BlockNum=%d", string(wavData.ID[:]), wavData.Size, blockNum)
}

//WavInfoType wav操作实例
type WavInfoType struct {
	Riff RiffType
	Fmt  WavFmtType
	Data WavDataType

	//create info
	createMs int64
}

//String ...
func (wavInfo *WavInfoType) String() string {
	f := &wavInfo.Fmt
	blockNum := len(wavInfo.Data.Sample)
	return fmt.Sprintf("SampleRate=%d,BitsPerSample=%d,Channels=%d,BlockNum=%d",
		f.SampleRate, f.BitsPerSample, f.Channels, blockNum)

}

//SetCreateTs ...
func (wavInfo *WavInfoType) SetCreateTs(timestampMs int64) {
	wavInfo.createMs = timestampMs
}

//CopyFormat 复制头部结构
func (wavInfo *WavInfoType) CopyFormat(w *WavInfoType) (err error) {
	wavInfo.Riff.ID = w.Riff.ID
	wavInfo.Riff.Size = w.Riff.Size
	wavInfo.Riff.Fmt = w.Riff.Fmt
	wavInfo.Fmt.ID = w.Fmt.ID
	wavInfo.Fmt.Size = w.Fmt.Size
	wavInfo.Fmt.AudioFormat = w.Fmt.AudioFormat
	wavInfo.Fmt.Channels = w.Fmt.Channels
	wavInfo.Fmt.SampleRate = w.Fmt.SampleRate
	wavInfo.Fmt.BytesPerSec = w.Fmt.BytesPerSec
	wavInfo.Fmt.BytesPerBlock = w.Fmt.BytesPerBlock
	wavInfo.Fmt.BitsPerSample = w.Fmt.BitsPerSample
	wavInfo.Data.ID = w.Data.ID
	wavInfo.Data.Size = w.Data.Size
	return
}

//ParseFromFile 从文件中导入
func (wavInfo *WavInfoType) ParseFromFile(absFile string) (err error) {
	absFile, err = filepath.Abs(absFile) //#nosec
	if err != nil {
		return err
	}
	fileHandler, err := os.Open(absFile) //#nosec
	if err != nil {
		return err
	}
	defer fileHandler.Close()

	_, err = fileHandler.Seek(0, os.SEEK_SET)
	if err != nil {
		return err
	}

	var pos int64
	var ch WavHeaderType

	//-----------------------------------------------------
	// RIFF header
	err = binary.Read(fileHandler, binary.LittleEndian, &wavInfo.Riff)
	if err != nil {
		return err
	}
	pos += int64(sizeHeader) + int64(len(tagWAVE))
	if wavInfo.Riff.ID != tagRIFF {
		return errors.New("File Format Not Riff")
	}
	if wavInfo.Riff.Fmt != tagWAVE {
		return errors.New("File Format Not Wave")
	}
	fileSize := int64(sizeHeader) + int64(wavInfo.Riff.Size)
	_ = fileSize

	//r := &wavInfo.Riff

	//-----------------------------------------------------
	// read all chunks

	var chunks = make(map[tag]*chunkLoc)

	for {
		err = binary.Read(fileHandler, binary.LittleEndian, &ch)
		if err != nil {
			if err == io.EOF {
				break
			}
			return err
		}
		pos += int64(sizeHeader)

		loc := chunkLoc{
			pos:  pos,
			size: int64(ch.Size),
		}

		_, err = fileHandler.Seek(loc.size, os.SEEK_CUR)
		if err != nil {
			return err
		}
		pos += loc.size // chunk data

		chunks[ch.ID] = &loc
	}

	// check fileHandler size
	if pos != fileSize {
		return errors.New("pos != fileSize")
	}

	//-----------------------------------------------------
	// chunk fmt_
	loc, ok := chunks[tagFmt]
	if !ok {
		return errors.New("wav: has not chunk \"fmt \"")
	}
	_, err = fileHandler.Seek(loc.pos-int64(sizeHeader), os.SEEK_SET)
	if err != nil {
		return err
	}
	err = binary.Read(fileHandler, binary.LittleEndian, &wavInfo.Fmt)
	if err != nil {
		return err
	}

	//-----------------------------------------------------
	// chunk data
	loc, ok = chunks[tagData]
	if !ok {
		return errors.New("wav: has not chunk \"data\"")
	}
	_, err = fileHandler.Seek(loc.pos, os.SEEK_SET)
	if err != nil {
		return err
	}

	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	blockSize := channel * bytePerSample

	wavInfo.Data.ID = tagData
	wavInfo.Data.Size = uint32(loc.size)

	blockNum := wavInfo.Data.Size / uint32(blockSize)
	wavInfo.Data.Sample = make([]SampleType, blockNum)

	_, err = fileHandler.Seek(loc.pos, os.SEEK_SET)
	if err != nil {
		return err
	}
	blockIdx := 0
	for i := 0; i < int(wavInfo.Data.Size); i += int(blockSize) {
		sample := &wavInfo.Data.Sample[blockIdx]
		blockIdx++
		for c := 0; c < int(channel); c++ {
			switch bytePerSample {
			case 1:
				var val uint8
				err = binary.Read(fileHandler, binary.LittleEndian, &val)
				//sample.val8s = append(sample.val8s,val)
				sample.val8s[c] = val
			case 2:
				var val int16
				err = binary.Read(fileHandler, binary.LittleEndian, &val)
				//sample.val16s = append(sample.val16s,val)
				sample.val16s[c] = val
				//fmt.Printf("pos=%d,val=%d\n",i,sample.val16s)
			case 4:
				var val float32
				err = binary.Read(fileHandler, binary.LittleEndian, &val)
				//sample.val32s = append(sample.val32s,val)
				sample.val32s[c] = val

			}
			if err != nil {
				return err
			}
		}
		//wavInfo.Data.Sample = append(wavInfo.Data.Sample,sample)
	}

	//for i:=0;i<len(wavInfo.Data.Sample);i++{
	//	sample := &wavInfo.Data.Sample[i]
	//	fmt.Printf("idx=%d,left=%d,right=%d\n",i,sample.val16s[0],sample.val16s[1])
	//}

	for id, chunk := range chunks {
		if id != tagData && id != tagFmt {
			//util.MainLogger.Error(fmt.Sprintf("unkonw chunk=%s,size=%d\n", string(id[:]), chunk.size))
			fmt.Printf("unkonw chunk=%s,size=%d\n", string(id[:]), chunk.size)
		}
	}
	return
}

//ParseFromBuffer 从buffer中导入
func (wavInfo *WavInfoType) ParseFromBuffer(buffer []byte) (err error) {
	var ch WavHeaderType

	bufferReader := bytes.NewBuffer(buffer)
	//-----------------------------------------------------
	// RIFF header
	err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Riff)
	if err != nil {
		return err
	}

	//pos := int64(sizeHeader) + int64(len(tagWAVE))
	if wavInfo.Riff.ID != tagRIFF {
		return errors.New("File Format Not Riff")
	}
	if wavInfo.Riff.Fmt != tagWAVE {
		return errors.New("File Format Not Wave")
	}
	fileSize := int64(sizeHeader) + int64(wavInfo.Riff.Size)
	_ = fileSize

	//r := &wavInfo.Riff

	//-----------------------------------------------------
	// read all chunks
	for {
		err = binary.Read(bufferReader, binary.LittleEndian, &ch)
		if err != nil {
			if err == io.EOF {
				//文件读取结束
				err = nil
				return
			}
			return err
		}

		//fmt格式的chunk
		if ch.ID == tagFmt {
			wavInfo.Fmt.WavHeaderType = ch
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.AudioFormat)
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.Channels)
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.SampleRate)
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.BytesPerSec)
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.BytesPerBlock)
			err = binary.Read(bufferReader, binary.LittleEndian, &wavInfo.Fmt.BitsPerSample)
			if err != nil {
				return err
			}
			continue
		}

		//data格式的chunk
		if ch.ID == tagData {
			channel := wavInfo.Fmt.Channels
			bytePerSample := wavInfo.Fmt.BitsPerSample / 8
			blockSize := channel * bytePerSample

			wavInfo.Data.ID = tagData
			wavInfo.Data.Size = ch.Size

			blockNum := wavInfo.Data.Size / uint32(blockSize)
			wavInfo.Data.Sample = make([]SampleType, blockNum)

			blockIdx := 0
			for i := 0; i < int(wavInfo.Data.Size); i += int(blockSize) {
				sample := &wavInfo.Data.Sample[blockIdx]
				blockIdx++
				for c := 0; c < int(channel); c++ {
					switch bytePerSample {
					case 1:
						var val uint8
						err = binary.Read(bufferReader, binary.LittleEndian, &val)
						//sample.val8s = append(sample.val8s,val)
						sample.val8s[c] = val
					case 2:
						var val int16
						err = binary.Read(bufferReader, binary.LittleEndian, &val)
						//sample.val16s = append(sample.val16s,val)
						sample.val16s[c] = val
						//fmt.Printf("pos=%d,val=%d\n",i,sample.val16s)
					case 4:
						var val float32
						err = binary.Read(bufferReader, binary.LittleEndian, &val)
						//sample.val32s = append(sample.val32s,val)
						sample.val32s[c] = val

					}
					if err != nil {
						return err
					}
				}
				//wavInfo.Data.Sample = append(wavInfo.Data.Sample,sample)
			}
			continue
		}

		//其他格式的chunk
		byteData := make([]byte, ch.Size)
		err = binary.Read(bufferReader, binary.LittleEndian, byteData)
	}
	return
}

//SaveToFile 保存到文件中
func (wavInfo *WavInfoType) SaveToFile(absFile string) (err error) {
	file, err := os.Create(absFile)
	if err != nil {
		return
	}
	defer file.Close()
	_, err = file.Seek(0, os.SEEK_SET)
	if err != nil {
		return
	}

	//calc size
	wavInfo.Data.Size = (uint32(wavInfo.Fmt.Channels) * uint32(wavInfo.Fmt.BitsPerSample) / 8) *
		uint32(len(wavInfo.Data.Sample))
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	wavInfo.Riff.Size = uint32(len(wavInfo.Riff.Fmt)) +
		uint32(sizeHeader) +
		wavInfo.Fmt.Size +
		uint32(sizeHeader) +
		wavInfo.Data.Size

	//----------------------------------------
	// RIFF header
	err = binary.Write(file, binary.LittleEndian, wavInfo.Riff)
	if err != nil {
		return err
	}

	//----------------------------------------
	// chunk fmt_
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	err = binary.Write(file, binary.LittleEndian, wavInfo.Fmt)
	if err != nil {
		return err
	}

	//----------------------------------------
	// chunk data
	ch := WavHeaderType{
		ID:   tagData,
		Size: wavInfo.Data.Size,
	}
	err = binary.Write(file, binary.LittleEndian, ch)
	if err != nil {
		return err
	}

	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		sample := &wavInfo.Data.Sample[i]
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(file, binary.LittleEndian, sample.val8s[c])
				if err != nil {
					return
				}

			}
		case 2:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(file, binary.LittleEndian, sample.val16s[c])
				if err != nil {
					return
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(file, binary.LittleEndian, sample.val32s[c])
				if err != nil {
					return
				}
			}
		}
	}
	return
}

//SaveToBuffer 保存到buffer中
func (wavInfo *WavInfoType) SaveToBuffer() (buffer []byte, err error) {

	//var bufferWriter   bytes.Buffer
	buffer = make([]byte, 0)
	bufferWriter := bytes.NewBuffer(buffer)

	//calc size
	wavInfo.Data.Size = (uint32(wavInfo.Fmt.Channels) * uint32(wavInfo.Fmt.BitsPerSample) / 8) *
		uint32(len(wavInfo.Data.Sample))
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	wavInfo.Riff.Size = uint32(len(wavInfo.Riff.Fmt)) +
		uint32(sizeHeader) +
		wavInfo.Fmt.Size +
		uint32(sizeHeader) +
		wavInfo.Data.Size

	//----------------------------------------
	// RIFF header
	err = binary.Write(bufferWriter, binary.LittleEndian, wavInfo.Riff)
	if err != nil {
		return
	}

	//----------------------------------------
	// chunk fmt_
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	err = binary.Write(bufferWriter, binary.LittleEndian, wavInfo.Fmt)
	if err != nil {
		return
	}

	//----------------------------------------
	// chunk data
	ch := WavHeaderType{
		ID:   tagData,
		Size: wavInfo.Data.Size,
	}
	err = binary.Write(bufferWriter, binary.LittleEndian, ch)
	if err != nil {
		return
	}

	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		sample := &wavInfo.Data.Sample[i]
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(bufferWriter, binary.LittleEndian, sample.val8s[c])
				if err != nil {
					return
				}
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(bufferWriter, binary.LittleEndian, sample.val16s[c])
				if err != nil {
					return
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {
				err = binary.Write(bufferWriter, binary.LittleEndian, sample.val32s[c])
				if err != nil {
					return
				}
			}
		}
	}
	buffer = bufferWriter.Bytes()
	return
}

//SaveToBuffer 保存到buffer中
func (wavInfo *WavInfoType) SaveToBufferWithChannel(voiceChannel int) (buffer []byte, err error) {

	//var bufferWriter   bytes.Buffer
	buffer = make([]byte, 0)
	bufferWriter := bytes.NewBuffer(buffer)

	//calc size
	channel := wavInfo.Fmt.Channels
	wavInfo.Fmt.Channels = 1
	wavInfo.Data.Size = (uint32(wavInfo.Fmt.Channels) * uint32(wavInfo.Fmt.BitsPerSample) / 8) *
		uint32(len(wavInfo.Data.Sample))
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	wavInfo.Riff.Size = uint32(len(wavInfo.Riff.Fmt)) +
		uint32(sizeHeader) +
		wavInfo.Fmt.Size +
		uint32(sizeHeader) +
		wavInfo.Data.Size

	//----------------------------------------
	// RIFF header
	err = binary.Write(bufferWriter, binary.LittleEndian, wavInfo.Riff)
	if err != nil {
		return
	}

	//----------------------------------------
	// chunk fmt_
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	err = binary.Write(bufferWriter, binary.LittleEndian, wavInfo.Fmt)
	if err != nil {
		return
	}

	//----------------------------------------
	// chunk data
	ch := WavHeaderType{
		ID:   tagData,
		Size: wavInfo.Data.Size,
	}
	err = binary.Write(bufferWriter, binary.LittleEndian, ch)
	if err != nil {
		return
	}


	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		sample := &wavInfo.Data.Sample[i]
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(bufferWriter, binary.LittleEndian, sample.val8s[c])
					if err != nil {
						return
					}
				}
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(bufferWriter, binary.LittleEndian, sample.val16s[c])
					if err != nil {
						return
					}
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(bufferWriter, binary.LittleEndian, sample.val32s[c])
					if err != nil {
						return
					}
				}
			}
		}
	}
	buffer = bufferWriter.Bytes()
	wavInfo.Fmt.Channels = 2
	return
}

//SaveToFile 保存到文件中
func (wavInfo *WavInfoType) SaveToFileWithChannel(absFile string, voiceChannel int) (err error) {
	file, err := os.Create(absFile)
	if err != nil {
		return
	}
	defer file.Close()
	_, err = file.Seek(0, io.SeekStart)
	if err != nil {
		return
	}

	//calc size
	channel := wavInfo.Fmt.Channels
	wavInfo.Fmt.Channels = 1
	wavInfo.Data.Size = (uint32(wavInfo.Fmt.Channels) * uint32(wavInfo.Fmt.BitsPerSample) / 8) *
		uint32(len(wavInfo.Data.Sample))
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	wavInfo.Riff.Size = uint32(len(wavInfo.Riff.Fmt)) +
		uint32(sizeHeader) +
		wavInfo.Fmt.Size +
		uint32(sizeHeader) +
		wavInfo.Data.Size

	//----------------------------------------
	// RIFF header
	err = binary.Write(file, binary.LittleEndian, wavInfo.Riff)
	if err != nil {
		return err
	}

	//----------------------------------------
	// chunk fmt_
	wavInfo.Fmt.Size = uint32(binary.Size(wavInfo.Fmt)) - uint32(sizeHeader)
	err = binary.Write(file, binary.LittleEndian, wavInfo.Fmt)
	if err != nil {
		return err
	}

	//----------------------------------------
	// chunk data
	ch := WavHeaderType{
		ID:   tagData,
		Size: wavInfo.Data.Size,
	}
	err = binary.Write(file, binary.LittleEndian, ch)
	if err != nil {
		return err
	}

	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		sample := &wavInfo.Data.Sample[i]
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(file, binary.LittleEndian, sample.val8s[c])
					if err != nil {
						return
					}
				}
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(file, binary.LittleEndian, sample.val16s[c])
					if err != nil {
						return
					}
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {
				if voiceChannel == c {
					err = binary.Write(file, binary.LittleEndian, sample.val32s[c])
					if err != nil {
						return
					}
				}
			}
		}
	}
	wavInfo.Fmt.Channels = 2
	return
}

//AdjusterVolume 调整音量
func (wavInfo *WavInfoType) AdjusterVolume(rateAsRaw float32) {
	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	const MaxUint8 = math.MaxUint8
	const MinUint8 = 0
	const MaxInt16 = math.MaxInt16
	const MinInt16 = math.MinInt16

	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val8s[c]
				clip := float64(val) * float64(rateAsRaw)
				if clip < MinUint8 {
					clip = MinUint8
				}
				if clip > MaxUint8 {
					clip = MaxUint8
				}
				//wavInfo.Data.Sample[i].val8s[c] = uint8((float32(val) * rateAsRaw))
				wavInfo.Data.Sample[i].val8s[c] = uint8(clip)
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				//val := wavInfo.Data.Sample[i].val16s[c]
				//wavInfo.Data.Sample[i].val16s[c] = int16((float32(val) * rateAsRaw))
				val := wavInfo.Data.Sample[i].val16s[c]
				clip := float64(val) * float64(rateAsRaw)
				if clip < MinInt16 {
					clip = MinInt16
				}
				if clip > MaxInt16 {
					clip = MaxInt16
				}
				wavInfo.Data.Sample[i].val16s[c] = int16(clip)
			}
		case 4:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val32s[c]
				wavInfo.Data.Sample[i].val32s[c] = val * rateAsRaw
			}
		}
	}
}

//Resample 重置采样率
func (wavInfo *WavInfoType) Resample(resampleRate uint32) {
	sampleRate := wavInfo.Fmt.SampleRate
	rate := float64(sampleRate) / float64(resampleRate)
	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	rawLen := len(wavInfo.Data.Sample)

	resampleData := make([]SampleType, 0)

	resampleIdx := 0
	for {
		rawIdx := int(float64(resampleIdx) * rate)
		if rawIdx < rawLen {
			sample := SampleType{}
			for c := 0; c < int(channel); c++ {
				switch bytePerSample {
				case 1:
					val := wavInfo.Data.Sample[rawIdx].val8s[c]
					//sample.val8s = append(sample.val8s,val)
					sample.val8s[c] = val
				case 2:
					val := wavInfo.Data.Sample[rawIdx].val16s[c]
					//sample.val16s = append(sample.val16s,val)
					sample.val16s[c] = val
				case 4:
					val := wavInfo.Data.Sample[rawIdx].val32s[c]
					//sample.val32s = append(sample.val32s,val)
					sample.val32s[c] = val
				}
			}
			resampleData = append(resampleData, sample)
		} else {
			break
		}
		resampleIdx++
	}

	wavInfo.Data.Sample = resampleData
	wavInfo.Fmt.SampleRate = resampleRate

}

//ConvertToFloat32 将采样值转换到 0 到 1 之间
func (wavInfo *WavInfoType) GetFloat32Samples(channel int, bytePerSample int) []float32 {
	//fmt.Println(wavInfo.cha)

	var floatSamples []float32

	var point float32
	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		sample := &wavInfo.Data.Sample[i]
		switch bytePerSample {
		case 1:
			point = float32(sample.val8s[channel]) / (1 << 8)
		case 2:
			point = float32(sample.val16s[channel]) / (1 << 15)
		case 4:
			point = sample.val32s[channel]
		}
		floatSamples = append(floatSamples, point)
	}
	return floatSamples
}

//Trim 切头切尾
func (wavInfo *WavInfoType) Trim(dbPercent float32) {
	channel := wavInfo.Fmt.Channels
	bytePerSample := wavInfo.Fmt.BitsPerSample / 8
	//blockSize := channel*bytePerSample

	const MaxUint8 = math.MaxUint8
	const MinUint8 = 0
	const MaxInt16 = math.MaxInt16
	const MinInt16 = math.MinInt16

	//trim head
	silenceHeadIdx := 0 //头部静音截止位置
	done := false
	for i := 0; i < len(wavInfo.Data.Sample); i++ {
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val8s[c]
				if float32(val) > MaxUint8*dbPercent {
					silenceHeadIdx = i
					done = true
					break
				}
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val16s[c]
				if float32(val) > MaxInt16*dbPercent {
					silenceHeadIdx = i
					done = true
					break
				}
				if float32(val) < MinInt16*dbPercent {
					silenceHeadIdx = i
					done = true
					break
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {

				val := wavInfo.Data.Sample[i].val32s[c]
				if float32(val) > math.MaxFloat32*dbPercent {
					silenceHeadIdx = i
					done = true
					break
				}
				if val < 0 && (-val > math.MaxFloat32*dbPercent) {
					silenceHeadIdx = i
					done = true
					break
				}
			}
		}

		if done {
			break
		}
	}

	//trim tail,截断尾部
	silenceTailIdx := len(wavInfo.Data.Sample) - 1 //尾部静音截止位置
	done = false
	for i := len(wavInfo.Data.Sample) - 1; i >= 0; i-- {
		switch bytePerSample {
		case 1:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val8s[c]
				if float32(val) > MaxUint8*dbPercent {
					silenceTailIdx = i
					done = true
					break
				}
			}
		case 2:
			for c := 0; c < int(channel); c++ {
				val := wavInfo.Data.Sample[i].val16s[c]
				if val >= 0 && float32(val) > float32(MaxInt16*dbPercent) {
					silenceTailIdx = i
					done = true
					break
				}
				if val < 0 && float32(val) < float32(MinInt16*dbPercent) {
					silenceTailIdx = i
					done = true
					break
				}
			}
		case 4:
			for c := 0; c < int(channel); c++ {

				val := wavInfo.Data.Sample[i].val32s[c]
				if float32(val) > math.MaxFloat32*dbPercent {
					silenceTailIdx = i
					done = true
					break
				}
				if val < 0 && (-val > math.MaxFloat32*dbPercent) {
					silenceTailIdx = i
					done = true
					break
				}
			}
		}

		if done {
			break
		}
	}

	wavInfo.Data.Sample = wavInfo.Data.Sample[:silenceTailIdx]
	wavInfo.Data.Sample = wavInfo.Data.Sample[silenceHeadIdx:]
}

func (wavInfo *WavInfoType) TrimFirstWithTime(milliseconds int64) error{
	sampleRate := wavInfo.Fmt.SampleRate
	sizeToTrim :=  int64(sampleRate) * milliseconds / 1000
	if int(sizeToTrim) >= len(wavInfo.Data.Sample) {
		return errors.New("check time err")
	}
	wavInfo.Data.Sample = wavInfo.Data.Sample[sizeToTrim:]
	return nil
}

func (wavInfo *WavInfoType) GetWavTime() int {
	return int(math.Ceil(float64(len(wavInfo.Data.Sample)) / float64(wavInfo.Fmt.SampleRate)))
}

//NewWavInfo 新建一个wav操作实例
func NewWavInfo() *WavInfoType {
	w := &WavInfoType{}
	return w
}