fft.cpp

一个KDE下的录音程序

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <math.h>

#include <qwidget.h>

#include "sound.h"
#include "fft.moc"

#include <X11/Xlib.h>

extern "C" {
  #include "soundfft.h"
}

#define FFT_MAX     8192
#define FFT_LEFT     100
#define FFT_RIGHT  10000
#define DB_MAX       0.0
#define DB_MIN    -100.0

/* ---------------------------------------------------------------------- */

FFTWindow::FFTWindow(QWidget *parent, char *name) : QWidget(parent,name,0)
{
    XColor color,dummy;
    Colormap map = DefaultColormapOfScreen
	(DefaultScreenOfDisplay(x11Display()));
    
    gc = XCreateGC(x11Display(),winId(),0,NULL);
    XAllocNamedColor(x11Display(),map,"white",&color,&dummy);
    back = color.pixel;
    XAllocNamedColor(x11Display(),map,"red",&color,&dummy);
    fore = color.pixel;

    /* flag: no init so far... */
    channels = 0;
    logmap = NULL;
    ylog = false;
}

void
FFTWindow::make_logmap()
{
    int   i,w,h;
    float freq,up;

    w = width();
    h = height();

    if (!w || !h || !channels)
	return;
    
    if (logmap) {
        free(logmap);
        free(segments);
	free(buffer);
	EndFFT();
    }
    logmap   = (int*) malloc((w+1)*sizeof(int));
    segments = (XSegment*)malloc((w)*sizeof(XSegment));
    buffer   = (short*)malloc(fft_size*sizeof(short)*channels);
    InitializeFFT(fft_size);

    up = log(FFT_RIGHT/FFT_LEFT)/log(2);
    for (i = 0; i <= w; i++) {
        freq = pow(2,up*i/w)* FFT_LEFT;
	logmap[i] = (int)(fft_size*freq/rate);
    }
    for (i = 0; i < w; i++) {
        segments[i].x1 = i;
        segments[i].x2 = i;
        segments[i].y2 = h;
    }
}

void
FFTWindow::calculate(unsigned char *data)
{
    int i,j;

    if (NULL == logmap) {
	fprintf(stderr,"Oops: fft no logmap (yet)\n");
	return;
    }

    switch (afmt) {
    case FMT_8BIT:
        for (i = 0; i < audio_size; i++)
            buffer[i] = (data[i] ^ 0x80) << 8;
        break;
#if 0
    case AFMT_S8:
        for (i = 0; i < audio_size; i++)
            buffer[i] = data[i] << 8;
        break;
#endif
    case FMT_16BIT:
        memcpy(buffer,data,audio_size);
#if 0
	/* byte swap */
	for (i = 0; i < fft_size; i++)
	    buffer[i] =
		((buffer[i] & 0xff00) >> 8) |
		((buffer[i] & 0x00ff) << 8);
	/* unsigned -> signed */
        if (afmt == AFMT_U16_LE || afmt == AFMT_U16_BE)
            for (i = 0; i < fft_size; i++)
                buffer[i] ^= 0x8000;
#endif
        break;
    default:
        fprintf(stderr,"oops(fft): unknown sound format\n");
        exit(1);
    }

    for (i = 0, lmax = 0; i < fft_size; i++)
        if ((j = abs((signed short)buffer[i])) > lmax)
            lmax = j;

    if (channels == 2) {
        for (i = 0, j = 0; i < fft_size; i++, j+=2)
            buffer[i] = (buffer[j]+buffer[j+1])>>1;
    }
    RealFFT(buffer);
}

void
FFTWindow::drawhist()
{
    XGCValues gcval;

    int re,im,ab;
    int i,j,max,w,h;
    int len = fft_size>>1;

    w = width();
    h = height();
    for (i = 0; i < w; i++) {
        max = 0;
        j = logmap[i];
        do {
            if (j >= len)
                break;
            re = buffer[BitReversed[j]];
            im = buffer[BitReversed[j]+1];
            ab = re*re+im*im;
            if (ab > max)
                max = ab;

            j++;
        } while (j < logmap[i+1]);
        if (ylog) {
            float dBVal = 20 * log10( sqrt(max)/FFT_MAX );
            max = (int)( h * ( dBVal-DB_MIN )/( DB_MAX-DB_MIN ));
        } else {
            max = (int)(sqrt(max) * h / FFT_MAX);
        }
        segments[i].y1 = h-max;
    }

    gcval.foreground = back;
    XChangeGC(x11Display(),gc,GCForeground,&gcval);
    XFillRectangle(x11Display(),winId(),gc,0,0,width(),height());

    gcval.foreground = fore;
    XChangeGC(x11Display(),gc,GCForeground,&gcval);
    XDrawSegments(x11Display(),winId(),gc,segments,w);
    if (ylog) {
	float dBVal = 20 * log10( (double)lmax/32768 );
	max = h - (int)( h * ( dBVal-DB_MIN )/( DB_MAX-DB_MIN ));
    } else {
	max = height() - lmax*height()/32768;
    }
    XDrawLine(x11Display(),winId(),gc,0,max,width(),max);
}

/* ---------------------------------------------------------------------- */

void
FFTWindow::resizeEvent(QResizeEvent *event)
{
    make_logmap();
}

void
FFTWindow::new_params(struct SOUNDPARAMS *p)
{
    afmt        = p->format;
    channels    = p->channels;
    rate        = p->rate;
    audio_size  = p->blocksize;

    fft_size = audio_size/channels/2;
    if (afmt != FMT_16BIT)
        fft_size *= 2;

    make_logmap();
}

void
FFTWindow::new_data(void *data)
{
    if (!channels || !isVisible())
	return;
    
    calculate((unsigned char*)data);
    drawhist();
}

void
FFTWindow::set_ylog(int linear)
{
    ylog = (linear==0);
    drawhist();
}