youpy / go-wav

A Go library to read/write WAVE(RIFF waveform Audio) Format

go-wav

A Go library to read/write WAVE(RIFF waveform Audio) Format

Usage

package main

import (
	"flag"
	"fmt"
	"github.com/youpy/go-wav"
	"io"
	"os"
)

func main() {
	infile_path := flag.String("infile", "", "wav file to read")
	flag.Parse()

	file, _ := os.Open(*infile_path)
	reader := wav.NewReader(file)

  	defer file.Close()

	for {
		samples, err := reader.ReadSamples()
		if err == io.EOF {
			break
		}

		for _, sample := range samples {
			fmt.Printf("L/R: %d/%d\n", reader.IntValue(sample, 0), reader.IntValue(sample, 1))
		}
	}
}

Supported format

Format

• PCM
• IEEE float (read-only)
• G.711 A-law (read-only)
• G.711 µ-law (read-only)

Number of channels

• 1(mono)
• 2(stereo)

Bits per sample

• 32-bit
• 24-bit
• 16-bit
• 8-bit

Documentation

• https://godoc.org/github.com/youpy/go-wav

See Also

• http://www-mmsp.ece.mcgill.ca/Documents/AudioFormats/WAVE/WAVE.html

go-wav's Issues

Are float32 files converted to Values [2]int and back to float64?

This is a deal-breaker here for me, in reader.go:

func (r *Reader) FloatValue(sample Sample, channel uint) float64 {
    // XXX
    return float64(r.IntValue(sample, channel)) / math.Pow(2, float64(r.format.BitsPerSample))
}

As is, this drastically distorts the levels of the source audio. What I need are the unmodified original float32 values converted to float64!

Audio duration

Hello there,

is possible to know the duration of the wave file in milliseconds?

how to calculate `Signal-to-noise ratio` and `vocal amplitude` from wav file?

i need to read wav file , calclate Signal-to-noise ratio and vocal amplitude .
my ConvertToDecibel code:

func ConvertToDecibel(arr int) float64 {
	ref := 1.0
	if arr != 0 {
		lgData := math.Log10(math.Abs(float64(arr)) / ref)
		return lgData * 20
	} else {
		return -60.0
	}

}

can you show your code about it?

WriteSamples is very slow

Hi, when I have big of []wav.sample , WriteSamples is very slow.

process to generate sample finish on 140ms
but WriteSamples take time over 6s to finish

and then I found the solution, change write method from

`func (w *Writer) WriteSamples(samples []Sample) (err error) {
bitsPerSample := w.Format.BitsPerSample
numChannels := w.Format.NumChannels

var i, b uint16
for _, sample := range samples {
	for i = 0; i < numChannels; i++ {
		value := toUint(sample.Values[i], int(bitsPerSample))

		for b = 0; b < bitsPerSample; b += 8 {
			err = binary.Write(w, binary.LittleEndian, uint8((value>>b)&math.MaxUint8))
			if err != nil {
				return
			}
		}
	}
}

return

}`

to

`
func (w *Writer) WriteSamples(samples []Sample) (err error) {
bitsPerSample := w.Format.BitsPerSample
numChannels := w.Format.NumChannels

var i, b uint16
var by []byte
for _, sample := range samples {
	for i = 0; i < numChannels; i++ {
		value := toUint(sample.Values[i], int(bitsPerSample))

		for b = 0; b < bitsPerSample; b += 8 {
			by = append(by, uint8((value>>b)&math.MaxUint8))
		}
	}
}

_, err = w.Write(by)
return

}
`

new WriteSample take time less than 1 sec to finish.

return wav header data

hope to get wav header data from format attr.
so i can detect wheater a 44 or 46-byte header.

Can I record a stream ?

I would like to use NewWriter with nsamples=0, and then when the writer stops update the wav header

Is this possible with go-wav?

add wav header to audio []byte

Hello,

i'm getting audio input and I would like to save it to file but after adding wav header file.

Then save it to .wav file instead of .pcm now..

How to proceed using your library ? Here is my code:

nowS := now.Format("20060102150405")
			pcmFile := fmt.Sprintf("%s/%s_%s.pcm", common.DISK, uid, nowS)
                        //[]byte data add header wav here before save
			ioutil.WriteFile(pcmFile, data, 0644)

can you provide an example about creating a wave file?

Hi,

I'm struggling to create a wave file, I tried this simple program, but it doesn't sound right! (pardon my comicity )

file, err := os.OpenFile("./t.wav", os.O_RDWR|os.O_CREATE, 0666)
        if err != nil {
                fmt.Println(err)
        }
        // 8BitStereo
        var numSamples uint32 = 10
        var numChannels uint16 = 2
        var sampleRate uint32 = 44100
        var bitsPerSample uint16 = 8

        writer := NewWriter(file, numSamples, numChannels, sampleRate, bitsPerSample)
        samples := make([]Sample, numSamples)

        samples[0].Values[0] = 255
        samples[0].Values[1] = 0
        samples[1].Values[0] = 123
        samples[1].Values[1] = 234
        samples[2].Values[0] = 255
        samples[2].Values[1] = 0
        samples[3].Values[0] = 123
        samples[3].Values[1] = 234
        samples[4].Values[0] = 255
        samples[4].Values[1] = 0
        samples[5].Values[0] = 123
        samples[5].Values[1] = 234
        samples[6].Values[0] = 255
        samples[6].Values[1] = 0
        samples[7].Values[0] = 123
        samples[7].Values[1] = 234
        samples[8].Values[0] = 255
        samples[8].Values[1] = 0
        samples[9].Values[0] = 123
        samples[9].Values[1] = 234

        err = writer.WriteSamples(samples)
        if err != nil {
                fmt.Println(err)
        }

        file.Close()

On mac, if I play I just hear a quick bump.

play t.wav 

t.wav:

 File Size: 48        Bit Rate: 8.47M
  Encoding: Unsigned PCM  
  Channels: 2 @ 8-bit    
Samplerate: 44100Hz      
Replaygain: off         
  Duration: 00:00:00.00  

In:100%  00:00:00.00 [00:00:00.00] Out:2     [!=====|=====!] Hd:0.0 Clip:0    
Done.

is the file right, but I didn't specified any sound duration?

Help!

[bug] stereo is not working

after I try to create wav file with 2 channel (stereo)
I found second channel is no data

v0.3.1

v0.3.2

I would like to fix this feature.