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refactor: use [][2] as audio buffers, instead of []float32

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Throughout sointu, we assume stereo audiobuffers, but were passing
around []float32. This had several issues, including len(buf)/2 and
numSamples*2 type of length conversion in many places. Also, it
caused one bug in a test case, causing it to succeed when it should
have not (the test had +-1 when it should have had +-2). This
refactoring makes it impossible to have odd length buffer issues.
This commit is contained in:
5684185+vsariola@users.noreply.github.com
2023-10-18 13:51:02 +03:00
parent bb0d4d6800
commit 38e9007bf8
14 changed files with 106 additions and 82 deletions
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27
oto/convertbuffer.go
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@ -2,6 +2,8 @@ package oto
import (
"math"
"github.com/vsariola/sointu"
)
// FloatBufferTo16BitLE is a naive helper method to convert []float32 buffers to
@ -9,17 +11,22 @@ import (
//
// Appends the encoded bytes into "to" slice, allowing you to preallocate the
// capacity or just use nil
func FloatBufferTo16BitLE(from []float32, to []byte) []byte {
func FloatBufferTo16BitLE(from sointu.AudioBuffer, to []byte) []byte {
for _, v := range from {
var uv int16
if v < -1.0 {
uv = -math.MaxInt16 // we are a bit lazy: -1.0 is encoded as -32767, as this makes math easier, and -32768 is unused
} else if v > 1.0 {
uv = math.MaxInt16
} else {
uv = int16(v * math.MaxInt16)
}
to = append(to, byte(uv&255), byte(uv>>8))
left := to16BitSample(v[0])
right := to16BitSample(v[1])
to = append(to, byte(left&255), byte(left>>8), byte(right&255), byte(right>>8))
}
return to
}
// convert float32 to int16, clamping to min and max
func to16BitSample(v float32) int16 {
if v < -1.0 {
return -math.MaxInt16
}
if v > 1.0 {
return math.MaxInt16
}
return int16(v * math.MaxInt16)
}

6
oto/convertbuffer_test.go
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@ -4,11 +4,12 @@ import (
"reflect"
"testing"
"github.com/vsariola/sointu"
"github.com/vsariola/sointu/oto"
)
func TestFloatBufferToBytes(t *testing.T) {
floats := []float32{0, 0.000489128, 0, 0.0019555532, 0, 0.0043964, 0, 0.007806882, 0, 0.012180306, 0, 0.017508084, 0, 0.023779746, 0, 0.030982954, 0, 0.039103523, 0, 0.04812544, 0, 0.05803088, 0, 0.068800256, 0, 0.08041221, 0, 0.09284368, 0, 0.10606992, 0, 0.120064534, 0, 0.13479951, 0, 0.1502453, 0, 0.16637078, 0, 0.18314338, 0, 0.20052913, 0, 0.21849263, 0, 0.23699719, 0, 0.2560048, 0, 0.27547634, 0, 0.29537144, 0, 0.31564865, 0, 0.33626547, 0, 0.35717854, 0, 0.37834346, 0, 0.39971504, 0, 0.4212474, 0, 0.4428938, 0, 0.46460703, 0, 0.48633927, 0, 0.50804216, 0, 0.52966696, 0, 0.5511646, 0, 0.57248586, 0, 0.5935812, 0, 0.6144009, 0, 0.63489544, 0, 0.6550152, 0, 0.67471063, 0, 0.6939326, 0, 0.712632, 0, 0.7307603, 0, 0.7482692, 0, 0.7651111, 0, 0.7812389}
floats := sointu.AudioBuffer{{0, 0.000489128}, {0, 0.0019555532}, {0, 0.0043964}, {0, 0.007806882}, {0, 0.012180306}, {0, 0.017508084}, {0, 0.023779746}, {0, 0.030982954}, {0, 0.039103523}, {0, 0.04812544}, {0, 0.05803088}, {0, 0.068800256}, {0, 0.08041221}, {0, 0.09284368}, {0, 0.10606992}, {0, 0.120064534}, {0, 0.13479951}, {0, 0.1502453}, {0, 0.16637078}, {0, 0.18314338}, {0, 0.20052913}, {0, 0.21849263}, {0, 0.23699719}, {0, 0.2560048}, {0, 0.27547634}, {0, 0.29537144}, {0, 0.31564865}, {0, 0.33626547}, {0, 0.35717854}, {0, 0.37834346}, {0, 0.39971504}, {0, 0.4212474}, {0, 0.4428938}, {0, 0.46460703}, {0, 0.48633927}, {0, 0.50804216}, {0, 0.52966696}, {0, 0.5511646}, {0, 0.57248586}, {0, 0.5935812}, {0, 0.6144009}, {0, 0.63489544}, {0, 0.6550152}, {0, 0.67471063}, {0, 0.6939326}, {0, 0.712632}, {0, 0.7307603}, {0, 0.7482692}, {0, 0.7651111}, {0, 0.7812389}}
bytes := []byte{0x0, 0x0, 0x10, 0x0, 0x0, 0x0, 0x40, 0x0, 0x0, 0x0, 0x90, 0x0, 0x0, 0x0, 0xff, 0x0, 0x0, 0x0, 0x8f, 0x1, 0x0, 0x0, 0x3d, 0x2, 0x0, 0x0, 0xb, 0x3, 0x0, 0x0, 0xf7, 0x3, 0x0, 0x0, 0x1, 0x5, 0x0, 0x0, 0x28, 0x6, 0x0, 0x0, 0x6d, 0x7, 0x0, 0x0, 0xce, 0x8, 0x0, 0x0, 0x4a, 0xa, 0x0, 0x0, 0xe2, 0xb, 0x0, 0x0, 0x93, 0xd, 0x0, 0x0, 0x5e, 0xf, 0x0, 0x0, 0x40, 0x11, 0x0, 0x0, 0x3b, 0x13, 0x0, 0x0, 0x4b, 0x15, 0x0, 0x0, 0x71, 0x17, 0x0, 0x0, 0xaa, 0x19, 0x0, 0x0, 0xf7, 0x1b, 0x0, 0x0, 0x55, 0x1e, 0x0, 0x0, 0xc4, 0x20, 0x0, 0x0, 0x42, 0x23, 0x0, 0x0, 0xce, 0x25, 0x0, 0x0, 0x66, 0x28, 0x0, 0x0, 0xa, 0x2b, 0x0, 0x0, 0xb7, 0x2d, 0x0, 0x0, 0x6d, 0x30, 0x0, 0x0, 0x29, 0x33, 0x0, 0x0, 0xeb, 0x35, 0x0, 0x0, 0xb0, 0x38, 0x0, 0x0, 0x77, 0x3b, 0x0, 0x0, 0x3f, 0x3e, 0x0, 0x0, 0x7, 0x41, 0x0, 0x0, 0xcb, 0x43, 0x0, 0x0, 0x8c, 0x46, 0x0, 0x0, 0x46, 0x49, 0x0, 0x0, 0xf9, 0x4b, 0x0, 0x0, 0xa4, 0x4e, 0x0, 0x0, 0x43, 0x51, 0x0, 0x0, 0xd6, 0x53, 0x0, 0x0, 0x5c, 0x56, 0x0, 0x0, 0xd2, 0x58, 0x0, 0x0, 0x36, 0x5b, 0x0, 0x0, 0x88, 0x5d, 0x0, 0x0, 0xc6, 0x5f, 0x0, 0x0, 0xee, 0x61, 0x0, 0x0, 0xfe, 0x63}
converted := oto.FloatBufferTo16BitLE(floats, nil)
for i, v := range converted {
@ -23,13 +24,14 @@ func TestFloatBufferToBytes(t *testing.T) {
}
func TestFloatBufferToBytesLimits(t *testing.T) {
floats := []float32{0, 1, -1, 0.999, -0.999}
floats := sointu.AudioBuffer{{0, 1}, {-1, 0.999}, {-0.999, 0}}
bytes := []byte{
0x0, 0x0,
0xFF, 0x7F, // float 1 = 0x7FFF = 0111111111111111
0x01, 0x80, // float -1 = 0x8001 = 1000000000000001
0xDE, 0x7F, // float 0.999 = 0x7FDE = 0111111111011110
0x22, 0x80, // float -0.999 = 0x8022 = 1000000000100010
0x0, 0x0,
}
converted := oto.FloatBufferTo16BitLE(floats, nil)
for i, v := range converted {

2
oto/oto.go
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@ -36,7 +36,7 @@ func (c *OtoContext) Close() error {
}
// Play implements the audio.Player interface for OtoPlayer
func (o *OtoOutput) WriteAudio(floatBuffer []float32) (err error) {
func (o *OtoOutput) WriteAudio(floatBuffer sointu.AudioBuffer) (err error) {
// we reuse the old capacity tmpBuffer by setting its length to zero. then,
// we save the tmpBuffer so we can reuse it next time
o.tmpBuffer = FloatBufferTo16BitLE(floatBuffer, o.tmpBuffer[:0])