func readSamples() ([]float64, float64, error) {
w, err := wav.New(os.Stdin)
if err != nil {
return nil, 0, err
}
log.Printf("format: %d, channels: %d, sample rate: %d, byte rate: %d, bps: %d, samples: %d, duration: %v\n",
w.Header.AudioFormat, w.Header.NumChannels, w.Header.SampleRate,
w.Header.ByteRate, w.Header.BitsPerSample, w.Samples, w.Duration)
rawSamples, err := w.ReadFloats(w.Samples)
if err != nil {
return nil, 0, err
}
flatSamples := flattenChannels(int(w.Header.NumChannels), rawSamples)
return flatSamples, float64(w.Header.SampleRate), nil
}
func (w *Wav) Info() (info codec.SongInfo, err error) {
var r io.ReadCloser
if len(w.initbuf) != 0 {
r = ioutil.NopCloser(bytes.NewBuffer(w.initbuf))
}
if r == nil {
r, _, err = w.Reader()
if err != nil {
return
}
}
wv, err := wav.New(r)
r.Close()
if err != nil {
return
}
return codec.SongInfo{
Time: wv.Duration,
}, nil
}
func (w *Wav) Init() (sampleRate, channels int, err error) {
if w.w == nil {
r, _, err := w.Reader()
if err != nil {
return 0, 0, err
}
buf := new(bytes.Buffer)
defer func() {
w.initbuf = buf.Bytes()
}()
wr, err := wav.New(io.TeeReader(r, buf))
if err != nil {
r.Close()
return 0, 0, err
}
w.r = r
w.w = wr
}
return int(w.w.SampleRate), int(w.w.NumChannels), nil
}
func getHits() ([]hit, error) {
w, err := wav.New(os.Stdin)
if err != nil {
return nil, err
}
log.Printf("format: %d, channels: %d, sample rate: %d, byte rate: %d, bps: %d, samples: %d, duration: %v\n",
w.Header.AudioFormat, w.Header.NumChannels, w.Header.SampleRate,
w.Header.ByteRate, w.Header.BitsPerSample, w.Samples, w.Duration)
winSize := int(w.Header.SampleRate * uint32(w.Header.NumChannels) / winDenom)
cursor := 0
hits := make([]hit, 0)
for {
rawSamples, err := w.ReadFloats(winSize)
if err != nil {
if err == io.EOF || err == io.ErrUnexpectedEOF {
break
} else {
return nil, err
}
}
if len(rawSamples) < winSize {
break
}
samples := flattenChannels(int(w.Header.NumChannels), rawSamples)
pxx, freqs := spectral.Pwelch(samples, float64(w.Header.SampleRate), &spectral.PwelchOptions{NFFT: 16384, Scale_off: true})
maxPower, maxPowerFreq := findPeak(pxx, freqs, 32, 880)
pMaxPower, pMaxPowerFreq := findPeak(pxx, freqs, 55, 170)
harmonic := true
if !dsputils.Float64Equal(maxPowerFreq, pMaxPowerFreq) {
if maxPowerFreq < pMaxPowerFreq || !areHarmonic(maxPower, pMaxPower) {
fmt.Printf("t = %v: %f !~ %f\n", fmtSeconds(float64(cursor)/float64(w.Header.SampleRate)), maxPowerFreq, pMaxPowerFreq)
harmonic = false
}
}
v1Freq := pMaxPowerFreq * 1.1
v1Pow := powerAtFreq(v1Freq, pxx, freqs)
p1Freq := pMaxPowerFreq * 1.2
p1Pow := powerAtFreq(p1Freq, pxx, freqs)
v2Freq := pMaxPowerFreq * 1.3
v2Pow := powerAtFreq(v2Freq, pxx, freqs)
p2Freq := pMaxPowerFreq * 1.4
p2Pow := powerAtFreq(p2Freq, pxx, freqs)
if harmonic && pMaxPower >= 0.00 && pMaxPowerFreq >= 55.0 && pMaxPowerFreq <= 160.0 && v1Pow < p1Pow && v2Pow < p2Pow {
hits = append(hits, hit{t: float64(cursor) / float64(w.Header.SampleRate), freq: pMaxPowerFreq, pow: pMaxPower})
}
cursor += len(rawSamples) / int(w.Header.NumChannels)
}
return hits, nil
}