feat: upgrade oto and output float audio

CHANGELOG.md

@@ -21,6 +21,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
   wrong scaling ([#150][i150])
 - Empty patch should not crash the native synth ([#148][i148])
 
+### Changed
+- The stand-alone apps now output floating point sound, as made possible by
+  upgrading oto-library to latest version. This way the tracker sound output
+  matches the compiled output better, as usually compiled intros output sound in
+  floating point. This might be important if OS sound drivers apply some audio
+  enhancemenets e.g. compressors to the audio.
+
 ## [0.4.1]
 ### Added
 - Clicking the parameter slider also selects that parameter ([#112][i112])

audio.go

@@ -5,6 +5,7 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"io"
 	"math"
 )
 
@@ -13,22 +14,30 @@ type (
 	// sample represented by [2]float32. [0] is left channel, [1] is right
 	AudioBuffer [][2]float32
 
-	// AudioOutput represents something where we can send audio e.g. audio output.
+	CloserWaiter interface {
-	// WriteAudio should block if not ready to accept audio e.g. buffer full.
+		io.Closer
-	AudioOutput interface {
+		Wait()
-		WriteAudio(buffer AudioBuffer) error
-		Close() error
 	}
 
-	// AudioContext represents the low-level audio drivers. There should be at most
+	// AudioContext represents the low-level audio drivers. There should be at
-	// one AudioContext at a time. The interface is implemented at least by
+	// most one AudioContext at a time. The interface is implemented at least by
 	// oto.OtoContext, but in future we could also mock it.
 	//
-	// AudioContext is used to create one or more AudioOutputs with Output(); each
+	// AudioContext is used to play one or more AudioSources. Playing can be
-	// can be used to output separate sound & closed when done.
+	// stopped by closing the returned io.Closer.
 	AudioContext interface {
-		Output() AudioOutput
+		Play(r AudioSource) CloserWaiter
-		Close() error
+	}
+
+	// AudioSource is an interface for reading audio samples into an
+	// AudioBuffer. Returns error if the buffer is not filled.
+	AudioSource interface {
+		ReadAudio(buf AudioBuffer) error
+	}
+
+	BufferSource struct {
+		buffer AudioBuffer
+		pos    int
 	}
 
 	// Synth represents a state of a synthesizer, compiled from a Patch.
@@ -145,6 +154,21 @@ func (buffer AudioBuffer) Fill(synth Synth) error {
 	return nil
 }
 
+func (b AudioBuffer) Source() *BufferSource {
+	return &BufferSource{buffer: b}
+}
+
+// ReadAudio reads audio samples from an AudioSource into an AudioBuffer.
+// Returns an error when the buffer is fully consumed.
+func (a *BufferSource) ReadAudio(buf AudioBuffer) error {
+	n := copy(buf, a.buffer[a.pos:])
+	a.pos += n
+	if a.pos >= len(a.buffer) {
+		return io.EOF
+	}
+	return nil
+}
+
 // Wav converts an AudioBuffer into a valid WAV-file, returned as a []byte
 // array.
 //

cmd/sointu-play/main.go

@@ -43,6 +43,7 @@ func main() {
 		*play = true // if the user gives nothing to output, then the default behaviour is just to play the file
 	}
 	var audioContext sointu.AudioContext
+	var playWaiter sointu.CloserWaiter
 	if *play {
 		var err error
 		audioContext, err = oto.NewContext()
@@ -50,7 +51,6 @@ func main() {
 			fmt.Fprintf(os.Stderr, "could not acquire oto AudioContext: %v\n", err)
 			os.Exit(1)
 		}
-		defer audioContext.Close()
 	}
 	process := func(filename string) error {
 		output := func(extension string, contents []byte) error {
@@ -98,11 +98,7 @@ func main() {
 			return fmt.Errorf("sointu.Play failed: %v", err)
 		}
 		if *play {
-			output := audioContext.Output()
+			playWaiter = audioContext.Play(buffer.Source())
-			defer output.Close()
-			if err := output.WriteAudio(buffer); err != nil {
-				return fmt.Errorf("error playing: %v", err)
-			}
 		}
 		if *rawOut {
 			raw, err := buffer.Raw(*pcm)
@@ -122,6 +118,9 @@ func main() {
 				return fmt.Errorf("error outputting .wav file: %v", err)
 			}
 		}
+		if *play {
+			playWaiter.Wait()
+		}
 		return nil
 	}
 	retval := 0

cmd/sointu-track/main.go

@@ -28,6 +28,16 @@ func (NullContext) BPM() (bpm float64, ok bool) {
 	return 0, false
 }
 
+type PlayerAudioSource struct {
+	*tracker.Player
+	playerProcessContext tracker.PlayerProcessContext
+}
+
+func (p *PlayerAudioSource) ReadAudio(buf sointu.AudioBuffer) error {
+	p.Player.Process(buf, p.playerProcessContext)
+	return nil
+}
+
 var cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`")
 var memprofile = flag.String("memprofile", "", "write memory profile to `file`")
 
@@ -49,7 +59,6 @@ func main() {
 		fmt.Println(err)
 		os.Exit(1)
 	}
-	defer audioContext.Close()
 	recoveryFile := ""
 	if configDir, err := os.UserConfigDir(); err == nil {
 		recoveryFile = filepath.Join(configDir, "Sointu", "sointu-track-recovery")
@@ -63,18 +72,10 @@ func main() {
 		f.Close()
 	}
 	tracker := gioui.NewTracker(model)
-	output := audioContext.Output()
+	audioCloser := audioContext.Play(&PlayerAudioSource{player, NullContext{}})
-	defer output.Close()
-	go func() {
-		buf := make(sointu.AudioBuffer, 1024)
-		ctx := NullContext{}
-		for {
-			player.Process(buf, ctx)
-			output.WriteAudio(buf)
-		}
-	}()
 	go func() {
 		tracker.Main()
+		audioCloser.Close()
 		if *cpuprofile != "" {
 			pprof.StopCPUProfile()
 			f.Close()

go.mod

@@ -6,7 +6,7 @@ require (
 	gioui.org v0.7.1
 	gioui.org/x v0.7.1
 	github.com/Masterminds/sprig v2.22.0+incompatible
-	github.com/hajimehoshi/oto v0.6.6
+	github.com/ebitengine/oto/v3 v3.3.0
 	golang.org/x/exp/shiny v0.0.0-20240707233637-46b078467d37
 	golang.org/x/text v0.16.0
 	gopkg.in/yaml.v2 v2.3.0
@@ -20,6 +20,7 @@ require (
 	git.wow.st/gmp/jni v0.0.0-20210610011705-34026c7e22d0 // indirect
 	github.com/Masterminds/goutils v1.1.0 // indirect
 	github.com/Masterminds/semver v1.5.0 // indirect
+	github.com/ebitengine/purego v0.8.0 // indirect
 	github.com/go-text/typesetting v0.1.1 // indirect
 	github.com/godbus/dbus/v5 v5.0.6 // indirect
 	github.com/google/uuid v1.1.2 // indirect
@@ -31,8 +32,7 @@ require (
 	golang.org/x/crypto v0.0.0-20210921155107-089bfa567519 // indirect
 	golang.org/x/exp v0.0.0-20240707233637-46b078467d37 // indirect
 	golang.org/x/image v0.18.0 // indirect
-	golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a // indirect
+	golang.org/x/sys v0.25.0 // indirect
-	golang.org/x/sys v0.22.0 // indirect
 	pipelined.dev/pipe v0.11.0 // indirect
 	pipelined.dev/signal v0.10.0 // indirect
 )

go.sum

@@ -19,6 +19,12 @@ github.com/Masterminds/sprig v2.22.0+incompatible h1:z4yfnGrZ7netVz+0EDJ0Wi+5VZC
 github.com/Masterminds/sprig v2.22.0+incompatible/go.mod h1:y6hNFY5UBTIWBxnzTeuNhlNS5hqE0NB0E6fgfo2Br3o=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/ebitengine/oto/v3 v3.3.0 h1:34lJpJLqda0Iee9g9p8RWtVVwBcOOO2YSIS2x4yD1OQ=
+github.com/ebitengine/oto/v3 v3.3.0/go.mod h1:MZeb/lwoC4DCOdiTIxYezrURTw7EvK/yF863+tmBI+U=
+github.com/ebitengine/oto/v3 v3.3.1 h1:d4McwGQuXOT0GL7bA5g9ZnaUEIEjQvG3hafzMy+T3qE=
+github.com/ebitengine/oto/v3 v3.3.1/go.mod h1:MZeb/lwoC4DCOdiTIxYezrURTw7EvK/yF863+tmBI+U=
+github.com/ebitengine/purego v0.8.0 h1:JbqvnEzRvPpxhCJzJJ2y0RbiZ8nyjccVUrSM3q+GvvE=
+github.com/ebitengine/purego v0.8.0/go.mod h1:iIjxzd6CiRiOG0UyXP+V1+jWqUXVjPKLAI0mRfJZTmQ=
 github.com/go-text/typesetting v0.1.1 h1:bGAesCuo85nXnEN5LmFMVGAGpGkCPtHrZLi//qD7EJo=
 github.com/go-text/typesetting v0.1.1/go.mod h1:d22AnmeKq/on0HNv73UFriMKc4Ez6EqZAofLhAzpSzI=
 github.com/go-text/typesetting-utils v0.0.0-20231211103740-d9332ae51f04 h1:zBx+p/W2aQYtNuyZNcTfinWvXBQwYtDfme051PR/lAY=
@@ -27,8 +33,6 @@ github.com/godbus/dbus/v5 v5.0.6 h1:mkgN1ofwASrYnJ5W6U/BxG15eXXXjirgZc7CLqkcaro=
 github.com/godbus/dbus/v5 v5.0.6/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/google/uuid v1.1.2 h1:EVhdT+1Kseyi1/pUmXKaFxYsDNy9RQYkMWRH68J/W7Y=
 github.com/google/uuid v1.1.2/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
-github.com/hajimehoshi/oto v0.6.6 h1:HYSZ8cYZqOL4iHugvbcfhNN2smiSOsBMaoSBi4nnWcw=
-github.com/hajimehoshi/oto v0.6.6/go.mod h1:0QXGEkbuJRohbJaxr7ZQSxnju7hEhseiPx2hrh6raOI=
 github.com/huandu/xstrings v1.3.2 h1:L18LIDzqlW6xN2rEkpdV8+oL/IXWJ1APd+vsdYy4Wdw=
 github.com/huandu/xstrings v1.3.2/go.mod h1:y5/lhBue+AyNmUVz9RLU9xbLR0o4KIIExikq4ovT0aE=
 github.com/imdario/mergo v0.3.11 h1:3tnifQM4i+fbajXKBHXWEH+KvNHqojZ778UH75j3bGA=
@@ -44,22 +48,14 @@ github.com/stretchr/testify v1.6.1 h1:hDPOHmpOpP40lSULcqw7IrRb/u7w6RpDC9399XyoNd
 github.com/stretchr/testify v1.6.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519 h1:7I4JAnoQBe7ZtJcBaYHi5UtiO8tQHbUSXxL+pnGRANg=
 golang.org/x/crypto v0.0.0-20210921155107-089bfa567519/go.mod h1:GvvjBRRGRdwPK5ydBHafDWAxML/pGHZbMvKqRZ5+Abc=
-golang.org/x/exp v0.0.0-20190306152737-a1d7652674e8/go.mod h1:CJ0aWSM057203Lf6IL+f9T1iT9GByDxfZKAQTCR3kQA=
 golang.org/x/exp v0.0.0-20240707233637-46b078467d37 h1:uLDX+AfeFCct3a2C7uIWBKMJIR3CJMhcgfrUAqjRK6w=
 golang.org/x/exp v0.0.0-20240707233637-46b078467d37/go.mod h1:M4RDyNAINzryxdtnbRXRL/OHtkFuWGRjvuhBJpk2IlY=
 golang.org/x/exp/shiny v0.0.0-20240707233637-46b078467d37 h1:SOSg7+sueresE4IbmmGM60GmlIys+zNX63d6/J4CMtU=
 golang.org/x/exp/shiny v0.0.0-20240707233637-46b078467d37/go.mod h1:3F+MieQB7dRYLTmnncoFbb1crS5lfQoTfDgQy6K4N0o=
-golang.org/x/image v0.0.0-20190227222117-0694c2d4d067/go.mod h1:kZ7UVZpmo3dzQBMxlp+ypCbDeSB+sBbTgSJuh5dn5js=
 golang.org/x/image v0.18.0 h1:jGzIakQa/ZXI1I0Fxvaa9W7yP25TqT6cHIHn+6CqvSQ=
 golang.org/x/image v0.18.0/go.mod h1:4yyo5vMFQjVjUcVk4jEQcU9MGy/rulF5WvUILseCM2E=
-golang.org/x/mobile v0.0.0-20190415191353-3e0bab5405d6/go.mod h1:E/iHnbuqvinMTCcRqshq8CkpyQDoeVncDDYHnLhea+o=
+golang.org/x/sys v0.25.0 h1:r+8e+loiHxRqhXVl6ML1nO3l1+oFoWbnlu2Ehimmi34=
-golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a h1:sYbmY3FwUWCBTodZL1S3JUuOvaW6kM2o+clDzzDNBWg=
+golang.org/x/sys v0.25.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/mobile v0.0.0-20231127183840-76ac6878050a/go.mod h1:Ede7gF0KGoHlj822RtphAHK1jLdrcuRBZg0sF1Q+SPc=
-golang.org/x/sys v0.0.0-20190312061237-fead79001313/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.0.0-20190429190828-d89cdac9e872/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
-golang.org/x/sys v0.22.0 h1:RI27ohtqKCnwULzJLqkv897zojh5/DwS/ENaMzUOaWI=
-golang.org/x/sys v0.22.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
 golang.org/x/text v0.16.0 h1:a94ExnEXNtEwYLGJSIUxnWoxoRz/ZcCsV63ROupILh4=
 golang.org/x/text v0.16.0/go.mod h1:GhwF1Be+LQoKShO3cGOHzqOgRrGaYc9AvblQOmPVHnI=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=

oto/convertbuffer.go

@@ -1,32 +0,0 @@
-package oto
-
-import (
-	"math"
-
-	"github.com/vsariola/sointu"
-)
-
-// FloatBufferTo16BitLE is a naive helper method to convert []float32 buffers to
-// 16-bit little-endian, but encoded in byte buffer
-//
-// Appends the encoded bytes into "to" slice, allowing you to preallocate the
-// capacity or just use nil
-func FloatBufferTo16BitLE(from sointu.AudioBuffer, to []byte) []byte {
-	for _, v := range from {
-		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)
-}

oto/convertbuffer_test.go

@@ -1,46 +0,0 @@
-package oto_test
-
-import (
-	"reflect"
-	"testing"
-
-	"github.com/vsariola/sointu"
-	"github.com/vsariola/sointu/oto"
-)
-
-func TestFloatBufferToBytes(t *testing.T) {
-	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 {
-		if bytes[i] != v {
-			t.Fail()
-			t.Errorf("Unexpected conversion output byte %x (expected %x) at position %v", v, bytes[i], i)
-		}
-	}
-	if !reflect.DeepEqual(converted, bytes) {
-		t.Fatalf("Unexpected conversion output from FloatBufferTo16BitLE")
-	}
-}
-
-func TestFloatBufferToBytesLimits(t *testing.T) {
-	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 {
-		if bytes[i] != v {
-			t.Fail()
-			t.Errorf("Unexpected conversion output byte %x (expected %x) at position %v", v, bytes[i], i)
-		}
-	}
-	if !reflect.DeepEqual(converted, bytes) {
-		t.Fatalf("Unexpected conversion output from FloatBufferTo16BitLE")
-	}
-}

oto/oto.go

@@ -1,55 +1,99 @@
 package oto
 
 import (
+	"encoding/binary"
+	"errors"
 	"fmt"
+	"math"
+	"sync"
 
-	"github.com/hajimehoshi/oto"
+	"github.com/ebitengine/oto/v3"
 	"github.com/vsariola/sointu"
 )
 
-type OtoContext oto.Context
+const latency = 2048 // in samples at 44100 Hz = ~46 ms
-type OtoOutput struct {
-	player    *oto.Player
-	tmpBuffer []byte
-}
 
-func (c *OtoContext) Output() sointu.AudioOutput {
+type (
-	return &OtoOutput{player: (*oto.Context)(c).NewPlayer(), tmpBuffer: make([]byte, 0)}
+	OtoContext oto.Context
-}
 
-const otoBufferSize = 8192
+	OtoPlayer struct {
+		player *oto.Player
+		reader *OtoReader
+	}
+
+	OtoReader struct {
+		audioSource sointu.AudioSource
+		tmpBuffer   sointu.AudioBuffer
+		waitGroup   sync.WaitGroup
+		err         error
+		errMutex    sync.RWMutex
+	}
+)
 
-// NewPlayer creates and initializes a new OtoPlayer
 func NewContext() (*OtoContext, error) {
-	context, err := oto.NewContext(44100, 2, 2, otoBufferSize)
+	op := oto.NewContextOptions{}
+	op.SampleRate = 44100
+	op.ChannelCount = 2
+	op.Format = oto.FormatFloat32LE
+	context, readyChan, err := oto.NewContext(&op)
 	if err != nil {
 		return nil, fmt.Errorf("cannot create oto context: %w", err)
 	}
+	<-readyChan
 	return (*OtoContext)(context), nil
 }
 
-func (c *OtoContext) Close() error {
+func (c *OtoContext) Play(r sointu.AudioSource) sointu.CloserWaiter {
-	if err := (*oto.Context)(c).Close(); err != nil {
+	reader := &OtoReader{audioSource: r}
-		return fmt.Errorf("cannot close oto context: %w", err)
+	reader.waitGroup.Add(1)
-	}
+	player := (*oto.Context)(c).NewPlayer(reader)
-	return nil
+	player.SetBufferSize(latency * 8)
+	player.Play()
+	return OtoPlayer{player: player, reader: reader}
 }
 
-// Play implements the audio.Player interface for OtoPlayer
+func (o OtoPlayer) Wait() {
-func (o *OtoOutput) WriteAudio(floatBuffer sointu.AudioBuffer) (err error) {
+	o.reader.waitGroup.Wait()
-	// 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])
-	if _, err := o.player.Write(o.tmpBuffer); err != nil {
-		return fmt.Errorf("cannot write to player: %w", err)
-	}
-	return nil
 }
 
-// Close disposes of resources
+func (o OtoPlayer) Close() error {
-func (o *OtoOutput) Close() error {
+	o.reader.closeWithError(errors.New("OtoPlayer was closed"))
-	if err := o.player.Close(); err != nil {
+	return o.player.Close()
-		return fmt.Errorf("cannot close oto player: %w", err)
+}
-	}
+
-	return nil
+func (o *OtoReader) Read(b []byte) (n int, err error) {
+	o.errMutex.RLock()
+	if o.err != nil {
+		o.errMutex.RUnlock()
+		return 0, o.err
+	}
+	o.errMutex.RUnlock()
+	if len(b)%8 != 0 {
+		return o.closeWithError(fmt.Errorf("oto: Read buffer length must be a multiple of 8"))
+	}
+	samples := len(b) / 8
+	if samples > len(o.tmpBuffer) {
+		o.tmpBuffer = append(o.tmpBuffer, make(sointu.AudioBuffer, samples-len(o.tmpBuffer))...)
+	} else if samples < len(o.tmpBuffer) {
+		o.tmpBuffer = o.tmpBuffer[:samples]
+	}
+	err = o.audioSource.ReadAudio(o.tmpBuffer)
+	if err != nil {
+		return o.closeWithError(err)
+	}
+	for i := range o.tmpBuffer {
+		binary.LittleEndian.PutUint32(b[i*8:], math.Float32bits(o.tmpBuffer[i][0]))
+		binary.LittleEndian.PutUint32(b[i*8+4:], math.Float32bits(o.tmpBuffer[i][1]))
+	}
+	return samples * 8, nil
+}
+
+func (o *OtoReader) closeWithError(err error) (int, error) {
+	o.errMutex.Lock()
+	defer o.errMutex.Unlock()
+	if o.err == nil {
+		o.err = err
+		o.waitGroup.Done()
+	}
+	return 0, err
 }