Add raw audio decoder

* Add Int16Interleaved and Int16NonInterleaved formats
* Add Float32Interleaved and Float32NonInterleaved formats
* Add unit tests
This commit is contained in:
Lukas Herman
2020-06-06 19:39:31 -04:00
parent 8d7947b594
commit 94b57d40e3
2 changed files with 473 additions and 0 deletions

159
pkg/wave/decoder.go Normal file
View File

@@ -0,0 +1,159 @@
package wave
import (
"encoding/binary"
"fmt"
"math"
)
// Format represents how audio is formatted in memory
type Format string
const (
FormatInt16Interleaved Format = "Int16Interleaved"
FormatInt16NonInterleaved = "Int16NonInterleaved"
FormatFloat32Interleaved = "Float32Interleaved"
FormatFloat32NonInterleaved = "Float32NonInterleaved"
)
// Decoder decodes raw chunk to Audio
type Decoder interface {
// Decode decodes raw chunk in endian byte order
Decode(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error)
}
// DecoderFunc is a proxy type for Decoder
type DecoderFunc func(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error)
func (f DecoderFunc) Decode(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error) {
return f(endian, chunk, channels)
}
// NewDecoder creates a decoder to decode raw audio data in the given format
func NewDecoder(f Format) (Decoder, error) {
var decoder DecoderFunc
switch f {
case FormatInt16Interleaved:
decoder = decodeInt16Interleaved
case FormatInt16NonInterleaved:
decoder = decodeInt16NonInterleaved
case FormatFloat32Interleaved:
decoder = decodeFloat32Interleaved
case FormatFloat32NonInterleaved:
decoder = decodeFloat32NonInterleaved
default:
return nil, fmt.Errorf("%s is not supported", f)
}
return decoder, nil
}
func calculateChunkInfo(chunk []byte, channels int, sampleSize int) (ChunkInfo, error) {
if channels <= 0 {
return ChunkInfo{}, fmt.Errorf("channels has to be greater than 0")
}
if sampleSize <= 0 {
return ChunkInfo{}, fmt.Errorf("sample size has to be greater than 0")
}
sampleLen := channels * sampleSize
if len(chunk)%sampleLen != 0 {
expectedLen := len(chunk) + (sampleLen - len(chunk)%sampleLen)
return ChunkInfo{}, fmt.Errorf("expected chunk to have a length of %d, but got %d", expectedLen, len(chunk))
}
return ChunkInfo{
Channels: channels,
Len: len(chunk) / (channels * sampleSize),
}, nil
}
func decodeInt16Interleaved(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error) {
sampleSize := 2
chunkInfo, err := calculateChunkInfo(chunk, channels, sampleSize)
if err != nil {
return nil, err
}
container := NewInt16Interleaved(chunkInfo)
sampleLen := sampleSize * channels
var i int
for offset := 0; offset+sampleLen <= len(chunk); offset += sampleLen {
for ch := 0; ch < channels; ch++ {
flatOffset := offset + ch*sampleSize
sample := endian.Uint16(chunk[flatOffset : flatOffset+sampleSize])
container.SetInt16(i, ch, Int16Sample(sample))
}
i++
}
return container, nil
}
func decodeInt16NonInterleaved(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error) {
sampleSize := 2
chunkInfo, err := calculateChunkInfo(chunk, channels, sampleSize)
if err != nil {
return nil, err
}
container := NewInt16NonInterleaved(chunkInfo)
chunkLen := len(chunk) / channels
for ch := 0; ch < channels; ch++ {
offset := ch * chunkLen
for i := 0; i < chunkInfo.Len; i++ {
flatOffset := offset + i*sampleSize
sample := endian.Uint16(chunk[flatOffset : flatOffset+sampleSize])
container.SetInt16(i, ch, Int16Sample(sample))
}
}
return container, nil
}
func decodeFloat32Interleaved(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error) {
sampleSize := 4
chunkInfo, err := calculateChunkInfo(chunk, channels, sampleSize)
if err != nil {
return nil, err
}
container := NewFloat32Interleaved(chunkInfo)
sampleLen := sampleSize * channels
var i int
for offset := 0; offset+sampleLen <= len(chunk); offset += sampleLen {
for ch := 0; ch < channels; ch++ {
flatOffset := offset + ch*sampleSize
sample := endian.Uint32(chunk[flatOffset : flatOffset+sampleSize])
sampleF := math.Float32frombits(sample)
container.SetFloat32(i, ch, Float32Sample(sampleF))
}
i++
}
return container, nil
}
func decodeFloat32NonInterleaved(endian binary.ByteOrder, chunk []byte, channels int) (Audio, error) {
sampleSize := 4
chunkInfo, err := calculateChunkInfo(chunk, channels, sampleSize)
if err != nil {
return nil, err
}
container := NewFloat32NonInterleaved(chunkInfo)
chunkLen := len(chunk) / channels
for ch := 0; ch < channels; ch++ {
offset := ch * chunkLen
for i := 0; i < chunkInfo.Len; i++ {
flatOffset := offset + i*sampleSize
sample := endian.Uint32(chunk[flatOffset : flatOffset+sampleSize])
sampleF := math.Float32frombits(sample)
container.SetFloat32(i, ch, Float32Sample(sampleF))
}
}
return container, nil
}

314
pkg/wave/decoder_test.go Normal file
View File

@@ -0,0 +1,314 @@
package wave
import (
"encoding/binary"
"math"
"reflect"
"testing"
)
func TestCalculateChunkInfo(t *testing.T) {
testCases := map[string]struct {
chunk []byte
channels int
sampleSize int
expected ChunkInfo
expectErr bool
}{
"InvalidChunkSize1": {
chunk: make([]byte, 3),
channels: 2,
sampleSize: 2,
expected: ChunkInfo{},
expectErr: true,
},
"InvalidChunkSize2": {
chunk: make([]byte, 4),
channels: 2,
sampleSize: 4,
expected: ChunkInfo{},
expectErr: true,
},
"InvalidChannels": {
chunk: nil,
channels: 0,
sampleSize: 2,
expected: ChunkInfo{},
expectErr: true,
},
"InvalidSampleSize": {
chunk: nil,
channels: 2,
sampleSize: 0,
expected: ChunkInfo{},
expectErr: true,
},
"Valid1": {
chunk: nil,
channels: 2,
sampleSize: 2,
expected: ChunkInfo{
Len: 0,
Channels: 2,
SamplingRate: 0,
},
expectErr: false,
},
"Valid2": {
chunk: make([]byte, 8),
channels: 2,
sampleSize: 4,
expected: ChunkInfo{
Len: 1,
Channels: 2,
SamplingRate: 0,
},
expectErr: false,
},
"Valid3": {
chunk: make([]byte, 4),
channels: 1,
sampleSize: 2,
expected: ChunkInfo{
Len: 2,
Channels: 1,
SamplingRate: 0,
},
expectErr: false,
},
}
for testCaseName, testCase := range testCases {
testCase := testCase
t.Run(testCaseName, func(t *testing.T) {
actual, err := calculateChunkInfo(testCase.chunk, testCase.channels, testCase.sampleSize)
if testCase.expectErr && err == nil {
t.Fatal("expected an error, but got nil")
} else if !testCase.expectErr && err != nil {
t.Fatalf("expected no error, but got %s", err)
} else if !testCase.expectErr && !reflect.DeepEqual(actual, testCase.expected) {
t.Errorf("Wrong chunk info calculation result,\nexpected:\n%+v\ngot:\n%+v", testCase.expected, actual)
}
})
}
}
func TestDecodeInt16Interleaved(t *testing.T) {
raw := []byte{
// 16 bits per channel
0x01, 0x02, 0x03, 0x04,
0x05, 0x06, 0x07, 0x08,
}
t.Run("BigEndian", func(t *testing.T) {
expected := &Int16Interleaved{
Data: []int16{
int16(binary.BigEndian.Uint16([]byte{0x01, 0x02})),
int16(binary.BigEndian.Uint16([]byte{0x03, 0x04})),
int16(binary.BigEndian.Uint16([]byte{0x05, 0x06})),
int16(binary.BigEndian.Uint16([]byte{0x07, 0x08})),
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeInt16Interleaved(binary.BigEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
t.Run("LittleEndian", func(t *testing.T) {
expected := &Int16Interleaved{
Data: []int16{
int16(binary.LittleEndian.Uint16([]byte{0x01, 0x02})),
int16(binary.LittleEndian.Uint16([]byte{0x03, 0x04})),
int16(binary.LittleEndian.Uint16([]byte{0x05, 0x06})),
int16(binary.LittleEndian.Uint16([]byte{0x07, 0x08})),
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeInt16Interleaved(binary.LittleEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
}
func TestDecodeInt16NonInterleaved(t *testing.T) {
raw := []byte{
// 16 bits per channel
0x01, 0x02, 0x03, 0x04,
0x05, 0x06, 0x07, 0x08,
}
t.Run("BigEndian", func(t *testing.T) {
expected := &Int16NonInterleaved{
Data: [][]int16{
{int16(binary.BigEndian.Uint16([]byte{0x01, 0x02})), int16(binary.BigEndian.Uint16([]byte{0x03, 0x04}))},
{int16(binary.BigEndian.Uint16([]byte{0x05, 0x06})), int16(binary.BigEndian.Uint16([]byte{0x07, 0x08}))},
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeInt16NonInterleaved(binary.BigEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
t.Run("LittleEndian", func(t *testing.T) {
expected := &Int16NonInterleaved{
Data: [][]int16{
{int16(binary.LittleEndian.Uint16([]byte{0x01, 0x02})), int16(binary.LittleEndian.Uint16([]byte{0x03, 0x04}))},
{int16(binary.LittleEndian.Uint16([]byte{0x05, 0x06})), int16(binary.LittleEndian.Uint16([]byte{0x07, 0x08}))},
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeInt16NonInterleaved(binary.LittleEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
}
func TestDecodeFloat32Interleaved(t *testing.T) {
raw := []byte{
// 32 bits per channel
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
}
t.Run("BigEndian", func(t *testing.T) {
expected := &Float32Interleaved{
Data: []float32{
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x01, 0x02, 0x03, 0x04})),
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x05, 0x06, 0x07, 0x08})),
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x09, 0x0a, 0x0b, 0x0c})),
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x0d, 0x0e, 0x0f, 0x10})),
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeFloat32Interleaved(binary.BigEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
t.Run("LittleEndian", func(t *testing.T) {
expected := &Float32Interleaved{
Data: []float32{
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x01, 0x02, 0x03, 0x04})),
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x05, 0x06, 0x07, 0x08})),
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x09, 0x0a, 0x0b, 0x0c})),
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x0d, 0x0e, 0x0f, 0x10})),
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeFloat32Interleaved(binary.LittleEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
}
func TestDecodeFloat32NonInterleaved(t *testing.T) {
raw := []byte{
// 32 bits per channel
0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f, 0x10,
}
t.Run("BigEndian", func(t *testing.T) {
expected := &Float32NonInterleaved{
Data: [][]float32{
{
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x01, 0x02, 0x03, 0x04})),
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x05, 0x06, 0x07, 0x08})),
},
{
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x09, 0x0a, 0x0b, 0x0c})),
math.Float32frombits(binary.BigEndian.Uint32([]byte{0x0d, 0x0e, 0x0f, 0x10})),
},
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeFloat32NonInterleaved(binary.BigEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
t.Run("LittleEndian", func(t *testing.T) {
expected := &Float32NonInterleaved{
Data: [][]float32{
{
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x01, 0x02, 0x03, 0x04})),
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x05, 0x06, 0x07, 0x08})),
},
{
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x09, 0x0a, 0x0b, 0x0c})),
math.Float32frombits(binary.LittleEndian.Uint32([]byte{0x0d, 0x0e, 0x0f, 0x10})),
},
},
Size: ChunkInfo{
Len: 2,
Channels: 2,
},
}
actual, err := decodeFloat32NonInterleaved(binary.LittleEndian, raw, 2)
if err != nil {
t.Fatal(err)
}
if !reflect.DeepEqual(expected, actual) {
t.Errorf("Wrong decode result,\nexpected:\n%+v\ngot:\n%+v", expected, actual)
}
})
}