package audio
|
|
import (
|
"math"
|
"sync"
|
"voicesnap/internal/logger"
|
|
"github.com/gen2brain/malgo"
|
)
|
|
const (
|
sampleRate = 16000
|
channels = 1
|
bitsPerSample = 16
|
silenceThreshold = 0.05
|
)
|
|
// InputDevice represents an audio input device.
|
type InputDevice struct {
|
Name string `json:"name"`
|
IsDefault bool `json:"isDefault"`
|
}
|
|
// Recorder captures audio from the default input device using malgo (miniaudio).
|
type Recorder struct {
|
mu sync.Mutex
|
|
ctx *malgo.AllocatedContext
|
device *malgo.Device
|
|
// PCM buffer (16-bit signed, little-endian)
|
pcmBuf []byte
|
|
// Preferred device name (empty = system default)
|
preferredDevice string
|
|
// State
|
isRecording bool
|
maxVolume float64
|
currentVolume float64
|
volumeCallback func(float64)
|
deviceChangeCb func(string)
|
}
|
|
// NewRecorder creates a new audio recorder backed by malgo.
|
func NewRecorder() *Recorder {
|
ctxConfig := malgo.ContextConfig{}
|
ctx, err := malgo.InitContext(nil, ctxConfig, nil)
|
if err != nil {
|
logger.Error("Failed to init malgo context: %v", err)
|
return &Recorder{}
|
}
|
return &Recorder{ctx: ctx}
|
}
|
|
// OnVolume registers a callback for real-time volume updates.
|
func (r *Recorder) OnVolume(fn func(float64)) {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
r.volumeCallback = fn
|
}
|
|
// OnDeviceChange registers a callback for audio device changes.
|
func (r *Recorder) OnDeviceChange(fn func(string)) {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
r.deviceChangeCb = fn
|
}
|
|
// ListInputDevices returns all available audio capture devices.
|
func (r *Recorder) ListInputDevices() []InputDevice {
|
if r.ctx == nil {
|
return nil
|
}
|
infos, err := r.ctx.Context.Devices(malgo.Capture)
|
if err != nil {
|
logger.Error("Failed to list devices: %v", err)
|
return nil
|
}
|
var result []InputDevice
|
for i, info := range infos {
|
result = append(result, InputDevice{
|
Name: info.Name(),
|
IsDefault: i == 0,
|
})
|
}
|
return result
|
}
|
|
// SetPreferredDevice sets the preferred device by name. Empty string = system default.
|
func (r *Recorder) SetPreferredDevice(name string) {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
r.preferredDevice = name
|
logger.Info("Preferred device set to: %q", name)
|
}
|
|
// Start begins recording from the preferred (or default) capture device.
|
func (r *Recorder) Start() error {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
|
if r.isRecording {
|
return nil
|
}
|
|
r.pcmBuf = nil
|
r.maxVolume = 0
|
r.currentVolume = 0
|
|
deviceConfig := malgo.DefaultDeviceConfig(malgo.Capture)
|
deviceConfig.Capture.Format = malgo.FormatS16
|
deviceConfig.Capture.Channels = channels
|
deviceConfig.SampleRate = sampleRate
|
deviceConfig.PeriodSizeInMilliseconds = 50
|
|
// Use preferred device if set
|
if r.preferredDevice != "" {
|
infos, err := r.ctx.Context.Devices(malgo.Capture)
|
if err == nil {
|
for _, info := range infos {
|
if info.Name() == r.preferredDevice {
|
deviceConfig.Capture.DeviceID = info.ID.Pointer()
|
break
|
}
|
}
|
}
|
}
|
|
callbacks := malgo.DeviceCallbacks{
|
Data: func(outputSamples, inputSamples []byte, framecount uint32) {
|
r.onData(inputSamples)
|
},
|
}
|
|
device, err := malgo.InitDevice(r.ctx.Context, deviceConfig, callbacks)
|
if err != nil {
|
return err
|
}
|
|
if err := device.Start(); err != nil {
|
device.Uninit()
|
return err
|
}
|
|
r.device = device
|
r.isRecording = true
|
logger.Info("Recording started (16kHz/16-bit/mono)")
|
return nil
|
}
|
|
// Stop stops recording and discards audio data.
|
func (r *Recorder) Stop() {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
|
r.stopDevice()
|
r.pcmBuf = nil
|
}
|
|
// StopAndGetSamples stops recording and returns the captured audio as float32 samples.
|
func (r *Recorder) StopAndGetSamples() []float32 {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
|
r.stopDevice()
|
|
if len(r.pcmBuf) < 2 {
|
return nil
|
}
|
|
// Convert 16-bit PCM to float32
|
numSamples := len(r.pcmBuf) / 2
|
samples := make([]float32, numSamples)
|
for i := 0; i < numSamples; i++ {
|
sample := int16(r.pcmBuf[i*2]) | int16(r.pcmBuf[i*2+1])<<8
|
samples[i] = float32(sample) / 32768.0
|
}
|
|
logger.Info("Recording stopped, %d samples captured", numSamples)
|
r.pcmBuf = nil
|
return samples
|
}
|
|
// HasVoiceActivity returns true if the max volume exceeded the silence threshold.
|
func (r *Recorder) HasVoiceActivity() bool {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
return r.maxVolume > silenceThreshold
|
}
|
|
// GetDeviceName returns the name of the current capture device.
|
func (r *Recorder) GetDeviceName() string {
|
if r.ctx == nil {
|
return "Default"
|
}
|
devices, err := r.ctx.Context.Devices(malgo.Capture)
|
if err != nil || len(devices) == 0 {
|
return "Default"
|
}
|
return devices[0].Name()
|
}
|
|
// Close releases all audio resources.
|
func (r *Recorder) Close() {
|
r.mu.Lock()
|
defer r.mu.Unlock()
|
|
r.stopDevice()
|
if r.ctx != nil {
|
r.ctx.Free()
|
r.ctx = nil
|
}
|
}
|
|
func (r *Recorder) stopDevice() {
|
if r.device != nil {
|
r.device.Stop()
|
r.device.Uninit()
|
r.device = nil
|
}
|
r.isRecording = false
|
}
|
|
func (r *Recorder) onData(input []byte) {
|
r.mu.Lock()
|
|
if !r.isRecording {
|
r.mu.Unlock()
|
return
|
}
|
|
// Append raw PCM data
|
r.pcmBuf = append(r.pcmBuf, input...)
|
|
// Calculate RMS volume
|
numSamples := len(input) / 2
|
if numSamples == 0 {
|
r.mu.Unlock()
|
return
|
}
|
|
var sum float64
|
for i := 0; i < len(input)-1; i += 2 {
|
sample := int16(input[i]) | int16(input[i+1])<<8
|
normalized := float64(sample) / 32768.0
|
sum += normalized * normalized
|
}
|
rms := math.Sqrt(sum / float64(numSamples))
|
volume := math.Min(1.0, rms*8)
|
|
r.currentVolume = volume
|
if volume > r.maxVolume {
|
r.maxVolume = volume
|
}
|
|
cb := r.volumeCallback
|
r.mu.Unlock()
|
|
// Invoke callback outside lock to prevent deadlock with app mutex
|
if cb != nil {
|
cb(volume)
|
}
|
}
|
