mirror of https://bitbucket.org/ausocean/av.git
Audiofiltering:
Increase the efficieny and stability of algorithms by making use of waitgroups and goroutines.
This commit is contained in:
ausocean-david
parent
80ab5e4768
commit
8231379a51
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@ -6,9 +6,9 @@ import(
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"os"
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"encoding/binary"
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"github.com/mjibson/go-dsp/fft"
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// "github.com/mjibson/go-dsp/window"
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"math/cmplx"
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"time"
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"sync"
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)
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// define constants used in the generation of the sound waves
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@ -21,18 +21,27 @@ const(
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func main() {
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var wg1, wg2 sync.WaitGroup
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start := time.Now()
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// generate two sine waves with different frequencies to test frequency response
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n := 2
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// generate sine waves with different frequencies to test frequency response
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n := 100
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wg1.Add(n)
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audio := make([][]float64, n)
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// for i:=0; i<n; i++ {
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// audio[i] = generate(float64((i)*(22000/n)))
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// }
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audio[0] = generate(2000)
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audio[1] = generate(10000)
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for i:=0; i<n; i++ {
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go func(i int, audio [][]float64, wg *sync.WaitGroup) {
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audio[i] = generate(float64((i)*(22000/n)))
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wg.Done()
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} (i, audio, &wg1)
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}
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// create filter
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filterLen := 500
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wg2.Add(1)
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ch := make(chan []float64, 1)
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go LowPass(filterLen, 5000, &wg2, ch)
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wg1.Wait()
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// combine audio
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combinedAudio := make([]float64, length)
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for i := range audio[0] {
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@ -41,25 +50,19 @@ func main() {
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combinedAudio[i] += audio[j][i]
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}
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}
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fmt.Println("audio generation:", time.Since(start))
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start = time.Now()
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filterLen := 500
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filter := LowPass(filterLen, 20000)
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fmt.Println("audio filter generation:", time.Since(start))
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start = time.Now()
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wg2.Wait()
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filter := <- ch
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// convolve sinc with audio
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filteredAudio := Convolve(combinedAudio, filter)
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fmt.Println("convolution:", time.Since(start))
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start = time.Now()
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SaveAudioData(filteredAudio, "lowpass")
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SaveAudioData(combinedAudio, "unfiltered")
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fmt.Println("audio saving:", time.Since(start))
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start = time.Now()
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// SaveAudioData(filter, "test")
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wg1.Add(2)
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go SaveAudioData(combinedAudio, "unfiltered", &wg1)
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wg2.Add(1)
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filteredAudio := Convolve(combinedAudio, filter, &wg2)
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wg2.Wait()
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go SaveAudioData(filteredAudio, "lowpass", &wg1)
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wg1.Wait()
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fmt.Println(time.Since(start))
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}
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@ -77,93 +80,31 @@ func generate(Frequency float64) []float64 {
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// generate samples and write to file
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for i := 0; i < int(nsamps); i++ {
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samp[i] = math.Sin(angle * Frequency * float64(i))
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samp[i] = math.Sin(angle * Frequency * float64(4*i))
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}
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return samp
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}
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func TopFive (a []float64) (topVal []float64, topI []int) {
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length := 5
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runMax := make([]float64, length, length)
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indices := make([]int, length, length)
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for i:=range a {
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switch {
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case a[i] > runMax[0]:
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for i:=0; i<4; i++ {
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runMax[4-i] = runMax[4-(1+i)]
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indices[4-i] = indices[4-(1+i)]
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}
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runMax[0] = a[i]
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indices[0] = i
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case a[i] > runMax[1]:
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for i:=0; i<3; i++ {
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runMax[4-i] = runMax[4-(1+i)]
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indices[4-i] = indices[4-(1+i)]
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}
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runMax[1] = a[i]
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indices[1] = i
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case a[i] > runMax[2]:
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for i:=0; i<2; i++ {
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runMax[4-i] = runMax[4-(1+i)]
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indices[4-i] = indices[4-(1+i)]
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}
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runMax[2] = a[i]
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indices[2] = i
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case a[i] > runMax[3]:
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for i:=0; i<1; i++ {
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runMax[4-i] = runMax[4-(1+i)]
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indices[4-i] = indices[4-(1+i)]
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}
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runMax[3] = a[i]
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indices[3] = i
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}
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}
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return runMax, indices
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}
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func Max (a []float64) float64 {
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var runMax float64 = -1
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for i:= range a {
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if math.Abs(a[i]) > runMax {
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runMax = math.Abs(a[i])
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}
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}
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return runMax
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}
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func LowPass (n int, fc float64) (filter []float64) {
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func LowPass (n int, fc float64, wg *sync.WaitGroup, ch chan []float64) {
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// n is number of points on either side of 0
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// determine digital frequency equivalent for fc
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fd := fc/(2*SampleRate)
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fd := (fc*4)/(2*SampleRate)
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// create sinc function
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return Sinc(n, fd)
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ch <- Sinc(n, fd)
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wg.Done()
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}
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func Convolve (x, h []float64) []float64 {
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func Convolve (x, h []float64, wg *sync.WaitGroup) []float64 {
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convLen := len(x)+len(h)
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y := make([]float64, convLen)
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for n:=0; n<convLen; n++ {
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go SubConvolve(n, x, h, y)
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}
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return y
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}
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func SubConvolve (n int, x, h, y []float64) {
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wg.Add(1)
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go func (n int, x, h, y []float64, wg *sync.WaitGroup) {
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var sum float64 = 0
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for k:=0; k<len(x); k++ {
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if n-k >= 0 && n-k < len(h) {
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@ -171,10 +112,15 @@ func SubConvolve (n int, x, h, y []float64) {
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}
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}
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y[n] = sum
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wg.Done()
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}(n, x, h, y, wg)
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}
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wg.Done()
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return y
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}
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func SaveAudioData (signal []float64, fileName string) {
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func SaveAudioData (signal []float64, fileName string, wg1 *sync.WaitGroup) {
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// compute fft of signal
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FFTaudio := fft.FFTReal(signal)
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@ -188,23 +134,32 @@ func SaveAudioData (signal []float64, fileName string) {
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for i := range spectrum {
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spectrum[i] = spectrum[i]/maximum
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}
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// spectrumAlt := spectrum[0:length/2 + 1]
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// SAVE
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wg1.Add(2)
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go func (fileName string, length int, spectrum []float64, wg1 *sync.WaitGroup) {
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file := fileName + ".txt"
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f, _ := os.Create(file)
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for i:=0; i<20000; i++ {
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fmt.Fprintf(f, "%v\n", /*10*math.Log10*/(spectrum[i]))
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}
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fmt.Printf("Saved spectrum values to: %s\n", fileName)
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wg1.Done()
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}(fileName, 44100, spectrum, wg1)
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file = fileName + ".bin"
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f, _ = os.Create(file)
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go func (fileName string, signal []float64, wg1 *sync.WaitGroup) {
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file := fileName + ".bin"
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f, _ := os.Create(file)
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var buf [8]byte
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for i:=0; i<length; i++ {
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binary.LittleEndian.PutUint32(buf[:], math.Float32bits(float32(signal[i])))
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_, _ = f.Write(buf[:])
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}
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fmt.Printf("Saved binary values to: %s\n", fileName)
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wg1.Done()
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}(fileName, signal, wg1)
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wg1.Done()
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}
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