Go WAV Codec

Latest: v0.1.0

Table of Contents

• Summary
• Installation
• Encoder
• Decoder
• More Examples
• Expected Chunk Formats
• Resources
• License

Summary

Waveform Audio File Format, commonly shortened to WAV, is an uncompressed audio format. WAV files are usually quite large since they are uncompressed.

This library includes an API that makes it easy to read and write WAV files in Go!

Installation

Using the go wav codec is easy. First, use go get to install the latest version of the library.

go get github.com/nvisal1/go-wav-codec

Next, include go wav codec in your application

import "github.com/nvisal1/go-wav-codec"

Encoder

The Encoder supports writing metadata and audio data to WAV files. This library includes support for writing the following metadata chunks

Chunk ID	Description
LIST	Includes support for type INFO. docs

(as most metadata chunks are frowned upon - they are not widely supported by applications)

Examples

Create a new Encoder

f, err := os.Create("./path/to/your/file")
if err != nil {
    panic(err)
}

defer f.Close()

e, err := NewEncoder(1, 2, 48000, 16, f)
if err != nil {
    panic(err)
}

Write audio data to a new file

a := []int{0,0,0,0} // This is your audio data

err = e.WriteAudioData(a, 0)
if err != nil {
    t.Error(err.Error())
}

err = e.Close()
if err != nil {
    t.Error(err.Error())
}

Write metadata to a new file

a := []int{0,0,0,0} // This is your audio data

err = e.WriteAudioData(a, 0)
if err != nil {
    t.Error(err.Error())
}

ic := &InfoChunk{
		Location:     "",
		Artist:       "artist",
		Software:     "",
		CreationDate: "",
		Copyright:    "",
		Title:        "",
		Engineer:     "",
		Genre:        "",
		Product:      "",
		Source:       "",
		Subject:      "",
		Comments:     "",
		Technician:   "",
		Keywords:     "",
		Medium:       "",
	}

err = e.WriteMetadata(ic)
if err != nil {
    t.Error(err

err = e.Close()
if err != nil {
    t.Error(err.Error())
}

Decoder

The Decoder includes support for reading metadata and audio data from WAV files. This library supports the following metadata chunks

Chunk ID	Description
LIST	Includes support for ADTL and INFO types. docs
SMPL	docs
FACT	docs
PLST	docs
CUE	docs
INST	docs

Examples

Create a new Decoder

f, err := os.Open("./path/to/your/file")
if err != nil {
    panic(err)
}

defer f.Close()

d := Decoder.NewDecoder(f)

Read a portion of audio data

a := make([]int, 0)
ad, err := d.ReadAudioData(100, 0)
if err != nil {
    panic(err)
}
a = append(a, ad...)

Read all the audio data in chunks

a := make([]int, 0)
ad, err := d.ReadAudioData(100, 0)
if err != nil {
    t.Error(err.Error())
}
a = append(a, ad...)

for {
    ad, err = d.ReadAudioData(100, 1)
    if err != nil {
        if err == io.EOF {
            break
        }
        panic(err)
    }
    a = append(a, ad...)
}

More Examples

More examples can be found in ./cmd

Expected Chunk Formats

fmt

Size (bytes)	Description	Value
4	Chunk ID	"fmt " (this library case insensitive)
4	Chunk Size	16 (this library does not support extra format bytes)
2	Audio Format (Compression Code)	1 (this library only supports PCM)
2	Number of Channels	1 - 65,535
4	Sample Rate	1 - 0xFFFFFFFF
4	Bytes Per Second	1 - 0xFFFFFFFF
2	Block Align	1 - 65,535
2	Bits Per Sample (Bit Depth)	2 - 65,535
N/A	Extra Format Bytes are not supported	N/A

fact

Size (bytes)	Description	Value
4	Chunk ID	"fact" (this library case insensitive)
4	Chunk Size	4 (this library only supports number of samples)
4	Number of Samples	1 - 0xFFFFFFFF

cue

Size	Description	Value
4	Chunk ID	"cue " (this library case insensitive)
4	Chunk Size	4 + (NumCuePoints * 24)
4	Number of Cue Points	number of cue points
N/A	Cue Points Start Here	N/A

cue point

Size	Description	Value
4	ID	unique identification value
4	Position	play order position
4	Data Chunk ID	RIFF ID of corresponding data chunk
4	Chunk Start	Byte Offset of Data Chunk
4	Block Start	Byte Offset to sample of First Channel
4	Sample Offset	Byte Offset to sample byte of First Channel

plst

Size	Description	Value
4	Chunk ID	"plst" (this library case insensitive)
4	Chunk Size	Number of Segments * 12
4	Number of Segments	1 - 0xFFFFFFFF

segment

Size	Description	Value
4	Cue Point ID	0 - 0xFFFFFFFF
4	Length (in samples)	1 - 0xFFFFFFFF
4	Number of Repeats	1 - 0xFFFFFFFF

list

Size	Description	Value
4	Chunk ID	"list" (this library case insensitive)
4	Chunk Size	depends on type
4	Type ID	"adtl" or "info" (this library case insensitive)

labl

Size	Description	Value
4	Chunk ID	"labl" (this library case insensitive)
4	Chunk Size	depends on text
4	Cue Point ID	0 - 0xFFFFFFFF
N/A	Text	N/A

ltxt

Size	Description	Value
4	Chunk ID	"ltxt" (this library case insensitive)
4	Chunk Size	depends on text
4	Cue Point ID	0 - 0xFFFFFFFF
4	Sample Length	0 - 0xFFFFFFFF
4	Purpose ID	0 - 0xFFFFFFFF
2	Country	0 - 0xFFFF
2	Language	0 - 0xFFFF
2	Dialect	0 - 0xFFFF
2	Code Page	0 - 0xFFFF
N/A	Text	N/A

note

Size	Description	Value
4	Chunk ID	"note" (this library case insensitive)
4	Chunk Size	depends on text
4	Cue Point ID	0 - 0xFFFFFFFF
N/A	Text	N/A

info chunks

Chunk ID	Description	Is Supported (by this library)
IARL	Location	✅
IART	Artist	✅
ICMS		⬜️
ICMT	Comments	✅
ICOP	Copyright	✅
ICRD	Creation Date	✅
ICRP		⬜️
IDIM		⬜️
IDPI		⬜️
IENG	Engineer	✅
IGNR	Genre	✅
IKEY	Keywords	✅
ILGT		⬜️
IMED	Medium	✅
INAM	Title	✅
IPLT		⬜️
IPRD	Product	✅
ISBJ	Subject	✅
ISFT	Software	✅
ISRC	Source	✅
ISRF		⬜️
ITCH	Technician	✅
ITRK		⬜️

smpl

Size	Description	Value
4	Chunk ID	"smpl" (this library case insensitive)
4	Chunk Size	36 + (Number of Sample Loops * 24) + Sampler Data
4	Manufacturer	0 - 0xFFFFFFFF
4	Product	0 - 0xFFFFFFFF
4	Sample Period	0 - 0xFFFFFFFF
4	MIDI Unity Note	0 - 127
4	MIDI Pitch Fraction	0 - 0xFFFFFFFF
4	SMPTE Format	0, 24, 25, 29, 30
4	SMPTE Offset	0 - 0xFFFFFFFF
4	Number of Sample Loops	0 - 0xFFFFFFFF
4	Sampler Data	0 - 0xFFFFFFFF
N/A	Sampler Loops Start Here	N/A

sampler loop

Size	Description	Value
4	Cue Point ID	0 - 0xFFFFFFFF
4	Type	0 - 0xFFFFFFFF
4	Start	0 - 0xFFFFFFFF
4	End	0 - 0xFFFFFFFF
4	Fraction	0 - 0xFFFFFFFF
4	Play Count	0 - 0xFFFFFFFF

inst

Size	Description	Value
4	Chunk ID	"inst" (this library case insensitive)
4	Chunk Size	7
1	Unshifted Note	0 - 127
1	Fine Tune (dB)	-50 - +50
1	Gain	-64 - +64
1	Low Note	0 - 127
1	High Note	0 - 127
1	Low Velocity	1 - 127
1	High Velocity	1 - 127

Resources

Website	Description	Link
musicg-api	Wav File Format	Here
recordingblogs	List Chunk (of a RIFF file)	Here
soundfile	WAVE PCM soundfile format	Here

License

Go Wav Codec is released under the MIT license. See LICENSE