lili/ggwave
1
0
Fork 0
mirror of https://github.com/ggerganov/ggwave.git synced 2026-02-07 09:18:01 +08:00
Code Issues Packages Projects Releases Wiki Activity

ggwave : add filter function

Browse Source 
Currently support the following filter:

- Hann window
- Hamming window
- First-order high-pass
This commit is contained in:
Georgi Gerganov
2022-07-12 22:31:15 +03:00
parent 1341b3d80e
commit 0ab93dfad3
2 changed files with 117 additions and 12 deletions
Download Patch File Download Diff File Expand all files Collapse all files

86
src/ggwave.cpp
View File

@@ -224,14 +224,14 @@ uint8_t getDSSMagic(int i) {
#endif
}
void FFT(float * f, int N, int * ip, float * w) {
rdft(N, 1, f, ip, w);
void FFT(float * f, int N, int * wi, float * wf) {
rdft(N, 1, f, wi, wf);
}
void FFT(const float * src, float * dst, int N, int * ip, float * w) {
void FFT(const float * src, float * dst, int N, int * wi, float * wf) {
memcpy(dst, src, N * sizeof(float));
FFT(dst, N, ip, w);
FFT(dst, N, wi, wf);
}
inline void addAmplitudeSmooth(
@@ -1300,10 +1300,82 @@ bool GGWave::computeFFTR(const float * src, float * dst, int N) {
return true;
}
bool GGWave::computeFFTR(const float * src, float * dst, int N, int * ip, float * w) {
FFT(src, dst, N, ip, w);
int GGWave::computeFFTR(const float * src, float * dst, int N, int * wi, float * wf) {
if (wi == nullptr) return 2*N;
if (wf == nullptr) return 3 + sqrt(N/2);
return true;
FFT(src, dst, N, wi, wf);
return 1;
}
int GGWave::filter(ggwave_Filter filter, float * waveform, int N, float p0, float p1, float * w) {
if (w == nullptr) {
switch (filter) {
case GGWAVE_FILTER_HANN: return N;
case GGWAVE_FILTER_HAMMING: return N;
case GGWAVE_FILTER_FIRST_ORDER_HIGH_PASS: return 11;
};
}
if (w[0] == 0.0f && w[1] == 0.0f) {
switch (filter) {
case GGWAVE_FILTER_HANN:
{
const float f = 2.0f*M_PI/(float)N;
for (int i = 0; i < N; i++) {
w[i] = 0.5f - 0.5f*cosf(f*(float)i);
}
} break;
case GGWAVE_FILTER_HAMMING:
{
const float f = 2.0f*M_PI/(float)N;
for (int i = 0; i < N; i++) {
w[i] = 0.54f - 0.46f*cosf(f*(float)i);
}
} break;
case GGWAVE_FILTER_FIRST_ORDER_HIGH_PASS:
{
const float th = 2.0f*M_PI*p0/p1;
const float g = cos(th)/(1.0f + sin(th));
w[0] = (1.0f + g)/2.0f;
w[1] = -((1.0f + g)/2.0f);
w[2] = 0.0f;
w[3] = -g;
w[4] = 0.0f;
w[5] = 0.0f;
w[6] = 0.0f;
w[7] = 0.0f;
w[8] = 0.0f;
} break;
};
}
switch (filter) {
case GGWAVE_FILTER_HANN:
case GGWAVE_FILTER_HAMMING:
{
for (int i = 0; i < N; i++) {
waveform[i] *= w[i];
}
} break;
case GGWAVE_FILTER_FIRST_ORDER_HIGH_PASS:
{
for (int i = 0; i < N; i++) {
float xn = waveform[i];
float yn = w[0]*xn + w[1]*w[5] + w[2]*w[6] + w[3]*w[7] + w[4]*w[8];
w[6] = w[5];
w[5] = xn;
w[8] = w[7];
w[7] = yn;
waveform[i] = yn;
}
} break;
};
return 1;
}
//