audio/internal/convert: add StereoF32

Updates #2160
This commit is contained in:
Hajime Hoshi 2024-07-21 10:29:38 +09:00
parent 4689d656aa
commit f63c1c8fc5
2 changed files with 176 additions and 0 deletions

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// Copyright 2024 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package convert
import (
"io"
)
type StereoF32 struct {
source io.ReadSeeker
mono bool
buf []byte
}
func NewStereoF32(source io.ReadSeeker, mono bool) *StereoF32 {
return &StereoF32{
source: source,
mono: mono,
}
}
func (s *StereoF32) Read(b []byte) (int, error) {
l := len(b) / 8 * 8
if s.mono {
l /= 2
}
if cap(s.buf) < l {
s.buf = make([]byte, l)
}
n, err := s.source.Read(s.buf[:l])
if err != nil && err != io.EOF {
return 0, err
}
if s.mono {
for i := 0; i < n/4; i++ {
b[8*i] = s.buf[4*i]
b[8*i+1] = s.buf[4*i+1]
b[8*i+2] = s.buf[4*i+2]
b[8*i+3] = s.buf[4*i+3]
b[8*i+4] = s.buf[4*i]
b[8*i+5] = s.buf[4*i+1]
b[8*i+6] = s.buf[4*i+2]
b[8*i+7] = s.buf[4*i+3]
}
n *= 2
} else {
copy(b[:n], s.buf[:n])
}
return n, err
}
func (s *StereoF32) Seek(offset int64, whence int) (int64, error) {
offset = offset / 8 * 8
if s.mono {
offset /= 2
}
return s.source.Seek(offset, whence)
}

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// Copyright 2024 The Ebitengine Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package convert_test
import (
"bytes"
"fmt"
"io"
"math"
"math/rand" // TODO: Use math/rand/v2 when the minimum supported version becomes Go 1.22.
"testing"
"github.com/hajimehoshi/ebiten/v2/audio/internal/convert"
)
func randFloat32s(n int) []float32 {
r := make([]float32, n)
for i := range r {
r[i] = rand.Float32()*2 - 1
}
return r
}
func TestStereoF32(t *testing.T) {
testCases := []struct {
Name string
In []float32
}{
{
Name: "nil",
In: nil,
},
{
Name: "-1, 0, 1",
In: []float32{-1, 0, 1},
},
{
Name: "8 0s",
In: []float32{0, 0, 0, 0, 0, 0, 0, 0},
},
{
Name: "random 256 values",
In: randFloat32s(256),
},
{
Name: "random 65536 values",
In: randFloat32s(65536),
},
}
for _, tc := range testCases {
tc := tc
for _, mono := range []bool{false, true} {
mono := mono
t.Run(fmt.Sprintf("%s (mono=%t)", tc.Name, mono), func(t *testing.T) {
var inBytes, outBytes []byte
for _, v := range tc.In {
b := math.Float32bits(v)
inBytes = append(inBytes, byte(b), byte(b>>8), byte(b>>16), byte(b>>24))
if mono {
// As the source is mono, the output should be stereo.
outBytes = append(outBytes, byte(b), byte(b>>8), byte(b>>16), byte(b>>24), byte(b), byte(b>>8), byte(b>>16), byte(b>>24))
} else {
outBytes = append(outBytes, byte(b), byte(b>>8), byte(b>>16), byte(b>>24))
}
}
s := convert.NewStereoF32(bytes.NewReader(inBytes), mono)
var got []byte
for {
var buf [97]byte
n, err := s.Read(buf[:])
got = append(got, buf[:n]...)
if err != nil {
if err != io.EOF {
t.Fatal(err)
}
break
}
if _, err := s.Seek(0, io.SeekCurrent); err != nil {
if err != io.EOF {
t.Fatal(err)
}
break
}
}
want := outBytes
if !bytes.Equal(got, want) {
t.Errorf("got: %v, want: %v", got, want)
}
})
}
}
}