revid: made start and stop change audio device state

revid/audio-input.go

@@ -46,15 +46,21 @@ const (
 	rbNextTimeout = 100 * time.Millisecond
 )
 
+const (
+	running = iota
+	paused
+	stopped
+)
+
 var log *logger.Logger
 
-// AudioInput holds everything we need to know about the audio input stream.
+// audioDevice holds everything we need to know about the audio input stream.
 // Note: At 44100 Hz sample rate, 2 channels and 16-bit samples, a period of 5 seconds
 // results in PCM data chunks of 882000 bytes. A longer period exceeds datastore's 1MB blob limit.
-type AudioInput struct {
+type audioDevice struct {
 	mu     sync.Mutex
 	source string // Name of audio source, or empty for the default source.
-	mode   string // Operating mode, either "Running", "Paused", or "Stopped".
+	mode   uint8  // Operating mode, either running, paused, or stopped.
 
 	dev       *alsa.Device // Audio input device.
 	ab        alsa.Buffer  // ALSA's buffer.
@@ -64,7 +70,7 @@ type AudioInput struct {
 	*AudioConfig
 }
 
-// AudioConfig provides parameters used by AudioInput.
+// AudioConfig provides parameters used by audioDevice.
 type AudioConfig struct {
 	SampleRate int
 	Channels   int
@@ -73,8 +79,8 @@ type AudioConfig struct {
 	Codec      uint8
 }
 
-// NewAudioInput initializes and returns an AudioInput struct which can be started, read from, and stopped.
+// NewAudioDevice initializes and returns an audioDevice struct which can be started, read from, and stopped.
-func NewAudioInput(cfg *AudioConfig) *AudioInput {
+func NewAudioDevice(cfg *AudioConfig) *audioDevice {
 	// Initialize logger.
 	logLevel := int(logger.Debug)
 	validLogLevel := true
@@ -89,7 +95,7 @@ func NewAudioInput(cfg *AudioConfig) *AudioInput {
 		log.Log(logger.Error, "Invalid log level was defaulted to Info")
 	}
 
-	a := &AudioInput{}
+	a := &audioDevice{}
 	a.AudioConfig = cfg
 
 	// Open the requested audio device.
@@ -104,27 +110,42 @@ func NewAudioInput(cfg *AudioConfig) *AudioInput {
 	rbLen := rbDuration / a.RecPeriod
 	a.rb = ring.NewBuffer(rbLen, a.chunkSize, rbTimeout)
 
-	a.mode = "Paused"
+	a.mode = paused
 
 	return a
 }
 
 // Start will start recording audio and writing to the output.
-func (a *AudioInput) Start() {
+func (a *audioDevice) Start() {
 	a.mu.Lock()
 	mode := a.mode
 	a.mu.Unlock()
 	switch mode {
-	case "Paused":
+	case paused:
+		// Start Recording
 		go a.input()
-	case "Stopped":
+		mode = running
-
+	case stopped:
+		// Open the audio device and start recording.
+		err := a.open()
+		if err != nil {
+			log.Log(logger.Fatal, "alsa.open failed", "error", err.Error())
+		}
+		go a.input()
+		mode = running
+	case running:
+		return
 	}
+	a.mu.Lock()
+	a.mode = mode
+	a.mu.Unlock()
 }
 
 // Stop will stop recording audio and close
-func (a *AudioInput) Stop() {
+func (a *audioDevice) Stop() {
-	a.mode = "Stopped"
+	a.mu.Lock()
+	a.mode = stopped
+	a.mu.Unlock()
 	if a.dev != nil {
 		log.Log(logger.Debug, "Closing", "source", a.source)
 		a.dev.Close()
@@ -133,14 +154,14 @@ func (a *AudioInput) Stop() {
 
 }
 
-// ChunkSize returns the AudioInput's chunkSize, ie. the number of bytes of audio written to output at a time.
+// ChunkSize returns the audioDevice's chunkSize, ie. the number of bytes of audio written to output at a time.
-func (a *AudioInput) ChunkSize() int {
+func (a *audioDevice) ChunkSize() int {
 	return a.chunkSize
 }
 
 // open or re-open the recording device with the given name and prepare it to record.
 // If name is empty, the first recording device is used.
-func (a *AudioInput) open() error {
+func (a *audioDevice) open() error {
 	if a.dev != nil {
 		log.Log(logger.Debug, "Closing", "source", a.source)
 		a.dev.Close()
@@ -248,16 +269,16 @@ func (a *AudioInput) open() error {
 
 // input continously records audio and writes it to the ringbuffer.
 // Re-opens the device and tries again if ASLA returns an error.
-func (a *AudioInput) input() {
+func (a *audioDevice) input() {
 	for {
 		a.mu.Lock()
 		mode := a.mode
 		a.mu.Unlock()
 		switch mode {
-		case "Paused":
+		case paused:
 			time.Sleep(time.Duration(a.RecPeriod) * time.Second)
 			continue
-		case "Stopped":
+		case stopped:
 			break
 		}
 		log.Log(logger.Debug, "Recording audio for period", "seconds", a.RecPeriod)
@@ -295,7 +316,7 @@ func (a *AudioInput) input() {
 
 // Read reads a full PCM chunk from the ringbuffer, returning the number of bytes read upon success.
 // Any errors returned are unexpected and should be considered fatal.
-func (a *AudioInput) Read(p []byte) (n int, err error) {
+func (a *audioDevice) Read(p []byte) (n int, err error) {
 	chunk, err := a.rb.Next(rbNextTimeout)
 	switch err {
 	case nil:
@@ -321,7 +342,7 @@ func (a *AudioInput) Read(p []byte) (n int, err error) {
 
 // formatBuffer returns an ALSA buffer that has the recording data from the ac's original ALSA buffer but stored
 // in the desired format specified by the ac's parameters.
-func (a *AudioInput) formatBuffer() alsa.Buffer {
+func (a *audioDevice) formatBuffer() alsa.Buffer {
 	var err error
 	a.mu.Lock()
 	wantChannels := a.Channels

revid/audio-input_test.go

@@ -8,7 +8,7 @@ import (
 	"bitbucket.org/ausocean/iot/pi/netsender"
 )
 
-func TestAudioInputNew(t *testing.T) {
+func TestAudioPipeline(t *testing.T) {
 	mts.Meta = meta.New()
 	var logger testLogger
 	ns, err := netsender.New(&logger, nil, nil, nil)
@@ -18,7 +18,10 @@ func TestAudioInputNew(t *testing.T) {
 
 	var c Config
 	c.Logger = &logger
-	c.Input = Audio
+	c.Input = File
+	c.InputPath = "../../test/test-data/av/input/original_8kHz_adpcm_test.pcm"
+	c.Outputs = []uint8{File}
+	c.OutputPath = "./test-temp"
 
 	rv, err := New(c, ns)
 	if err != nil {

revid/revid.go

@@ -272,7 +272,7 @@ func (r *Revid) setupPipeline(mtsEnc func(dst io.WriteCloser, rate, mediaType in
 	case File:
 		r.setupInput = r.setupInputForFile
 	case Audio:
-		r.setupInput = r.startAudioInput
+		r.setupInput = r.startAudioDevice
 	}
 
 	switch r.config.InputCodec {
@@ -613,12 +613,12 @@ func (r *Revid) setupInputForFile() (func() error, error) {
 
 	// TODO(kortschak): Maybe we want a context.Context-aware parser that we can stop.
 	r.wg.Add(1)
-	go r.processFrom(f, time.Second/time.Duration(r.config.FrameRate), 0)
+	go r.processFrom(f, 0, 0)
 	return func() error { return f.Close() }, nil
 }
 
-// startAudioInput is used to start capturing audio from an audio device and processing it.
+// startAudioDevice is used to start capturing audio from an audio device and processing it.
-func (r *Revid) startAudioInput() (func() error, error) {
+func (r *Revid) startAudioDevice() (func() error, error) {
 	ac := &AudioConfig{
 		SampleRate: r.config.SampleRate,
 		Channels:   r.config.Channels,
@@ -626,7 +626,7 @@ func (r *Revid) startAudioInput() (func() error, error) {
 		BitDepth:   r.config.BitDepth,
 		Codec:      r.config.InputCodec,
 	}
-	ai := NewAudioInput(ac)
+	ai := NewAudioDevice(ac)
 	r.wg.Add(1)
 	go r.processFrom(ai, time.Second/time.Duration(r.config.WriteRate), ai.ChunkSize())
 	return func() error {

revid/senders.go

@@ -57,7 +57,7 @@ type httpSender struct {
 	log    func(lvl int8, msg string, args ...interface{})
 }
 
-// newMinimalHttpSender returns a pointer to a new minimalHttpSender.
+// newHttpSender returns a pointer to a new httpSender.
 func newHttpSender(ns *netsender.Sender, log func(lvl int8, msg string, args ...interface{})) *httpSender {
 	return &httpSender{
 		client: ns,