commit 70ecaae62eb908f0784cce406138fcc6787f718e
parent df59b4d1e2a45a1b6351889fb713a411d494729f
Author: Alexander Kojevnikov <alexander@kojevnikov.com>
Date: Sun, 3 Apr 2016 12:47:01 -0700
Change the window function
And add Blackman-Harris in addition to Hann and Hamming.
References #94.
Diffstat:
5 files changed, 38 insertions(+), 6 deletions(-)
diff --git a/MANUAL.md b/MANUAL.md
@@ -53,6 +53,9 @@ On OS X use the Command key instead of Ctrl.
`Ctrl-Shift-up`, `Ctrl-Shift-down`
: Change the upper limit of the dynamic range in dBFS.
+`f`, `F`
+: Change the DFT window function.
+
`s`, `S`
: Change the DFT window size.
diff --git a/src/spek-pipeline.cc b/src/spek-pipeline.cc
@@ -25,6 +25,7 @@ struct spek_pipeline
{
std::unique_ptr<AudioFile> file;
std::unique_ptr<FFTPlan> fft;
+ enum window_function window_function;
int samples;
spek_pipeline_cb cb;
void *cb_data;
@@ -60,6 +61,7 @@ static void reader_sync(struct spek_pipeline *p, int pos);
struct spek_pipeline * spek_pipeline_open(
std::unique_ptr<AudioFile> file,
std::unique_ptr<FFTPlan> fft,
+ enum window_function window_function,
int samples,
spek_pipeline_cb cb,
void *cb_data
@@ -68,6 +70,7 @@ struct spek_pipeline * spek_pipeline_open(
spek_pipeline *p = new spek_pipeline();
p->file = std::move(file);
p->fft = std::move(fft);
+ p->window_function = window_function;
p->samples = samples;
p->cb = cb;
p->cb_data = cb_data;
@@ -319,6 +322,19 @@ static void reader_sync(struct spek_pipeline *p, int pos)
pthread_mutex_unlock(&p->worker_mutex);
}
+static float get_window(enum window_function f, int i, float *coss, int n) {
+ switch (f) {
+ case WINDOW_HANN:
+ return 0.5f * (1.0f - coss[i]);
+ case WINDOW_HAMMING:
+ return 0.53836f - 0.46164f * coss[i];
+ case WINDOW_BLACKMAN_HARRIS:
+ return 0.35875f - 0.48829f * coss[i] + 0.14128f * coss[2*i % n] - 0.01168f * coss[3*i % n];
+ default:
+ assert(false);
+ }
+}
+
static void * worker_func(void *pp)
{
struct spek_pipeline *p = (spek_pipeline*)pp;
@@ -370,11 +386,7 @@ static void * worker_func(void *pp)
prev_head = head;
for (int i = 0; i < p->nfft; i++) {
float val = p->input[(p->input_size + head - p->nfft + i) % p->input_size];
- // TODO: allow the user to chose the window function
- // Hamming window.
- // val *= 0.53836f - 0.46164f * coss[i];
- // Hann window.
- val *= 0.5f * (1.0f - p->coss[i]);
+ val *= get_window(p->window_function, i, p->coss, p->nfft);
p->fft->set_input(i, val);
}
p->fft->execute();
diff --git a/src/spek-pipeline.h b/src/spek-pipeline.h
@@ -7,11 +7,20 @@ class AudioFile;
class FFTPlan;
struct spek_pipeline;
+enum window_function {
+ WINDOW_HANN,
+ WINDOW_HAMMING,
+ WINDOW_BLACKMAN_HARRIS,
+ WINDOW_COUNT,
+ WINDOW_DEFAULT = WINDOW_HANN,
+};
+
typedef void (*spek_pipeline_cb)(int bands, int sample, float *values, void *cb_data);
struct spek_pipeline * spek_pipeline_open(
std::unique_ptr<AudioFile> file,
std::unique_ptr<FFTPlan> fft,
+ enum window_function window_function,
int samples,
spek_pipeline_cb cb,
void *cb_data
diff --git a/src/spek-spectrogram.cc b/src/spek-spectrogram.cc
@@ -5,7 +5,6 @@
#include "spek-audio.h"
#include "spek-events.h"
#include "spek-fft.h"
-#include "spek-pipeline.h"
#include "spek-platform.h"
#include "spek-ruler.h"
#include "spek-utils.h"
@@ -48,6 +47,7 @@ SpekSpectrogram::SpekSpectrogram(wxFrame *parent) :
audio(new Audio()), // TODO: refactor
fft(new FFT()),
pipeline(NULL),
+ window_function(WINDOW_DEFAULT),
duration(0.0),
sample_rate(0),
palette(PALETTE_DEFAULT),
@@ -102,6 +102,11 @@ void SpekSpectrogram::on_char(wxKeyEvent& evt)
this->urange = spek_min(this->urange + 1, MAX_RANGE);
} else if (CS && D) {
this->urange = spek_max(this->urange - 1, this->lrange + 1);
+ } else if (S && evt.GetKeyCode() == 'F') {
+ this->window_function = (enum window_function) ((this->window_function + 1) % WINDOW_COUNT);
+ } else if (N && evt.GetKeyCode() == 'f') {
+ this->window_function =
+ (enum window_function) ((this->window_function - 1 + WINDOW_COUNT) % WINDOW_COUNT);
} else if (S && evt.GetKeyCode() == 'S') {
this->fft_bits = spek_min(this->fft_bits + 1, MAX_FFT_BITS);
this->create_palette();
@@ -358,6 +363,7 @@ void SpekSpectrogram::start()
this->pipeline = spek_pipeline_open(
this->audio->open(std::string(this->path.utf8_str())),
this->fft->create(this->fft_bits),
+ this->window_function,
samples,
pipeline_cb,
this
diff --git a/src/spek-spectrogram.h b/src/spek-spectrogram.h
@@ -5,6 +5,7 @@
#include <wx/wx.h>
#include "spek-palette.h"
+#include "spek-pipeline.h"
class Audio;
class FFT;
@@ -34,6 +35,7 @@ private:
std::unique_ptr<Audio> audio;
std::unique_ptr<FFT> fft;
spek_pipeline *pipeline;
+ enum window_function window_function;
wxString path;
wxString desc;
double duration;
