sm64pc/tools/audiofile-0.3.6/examples/power.c

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2020-05-05 12:15:53 +00:00
/*
This program is derived from Chris Vaill's normalize program
and has been modified to use the Audio File Library for file
reading and audio data conversion.
Copyright (C) 2001, Silicon Graphics, Inc.
Copyright (C) 1999-2001, Chris Vaill
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
power.c
Calculate the power and peak amplitudes of an audio file.
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <audiofile.h>
#ifndef TRUE
#define TRUE 1
#endif
#ifndef FALSE
#define FALSE 0
#endif
struct smooth
{
double *buf;
int length, start, n;
};
static double get_smoothed_data (struct smooth *s)
{
int i;
double smoothed;
smoothed = 0;
for (i = 0; i < s->n; i++)
smoothed += s->buf[i];
smoothed = smoothed / s->n;
return smoothed;
}
void print_power (char *filename);
int main (int argc, char **argv)
{
int i;
if (argc < 2)
{
fprintf(stderr, "usage: %s filename [more filenames...]\n",
argv[0]);
exit(EXIT_FAILURE);
}
for (i=1; i<argc; i++)
print_power(argv[i]);
return 0;
}
void print_power (char *filename)
{
AFfilehandle file;
double *sums, *frames;
int channelCount, windowSize, frameCount;
int i, c;
struct smooth *powsmooth;
int winStart, winEnd;
int lastWindow = FALSE;
double pow, maxpow;
double level, peak, minSample = 1, maxSample = -1;
file = afOpenFile(filename, "r", NULL);
if (file == AF_NULL_FILEHANDLE)
{
fprintf(stderr, "Could not open file %s.\n", filename);
return;
}
channelCount = afGetChannels(file, AF_DEFAULT_TRACK);
windowSize = afGetRate(file, AF_DEFAULT_TRACK) / 100;
frameCount = afGetFrameCount(file, AF_DEFAULT_TRACK);
sums = calloc(channelCount, sizeof (double));
for (c=0; c<channelCount; c++)
sums[c] = 0;
frames = calloc(channelCount * windowSize, sizeof (double));
afSetVirtualSampleFormat(file, AF_DEFAULT_TRACK, AF_SAMPFMT_DOUBLE,
sizeof (double));
powsmooth = calloc(channelCount, sizeof (struct smooth));
for (c=0; c<channelCount; c++)
{
/* Use a 100-element (1 second) window. */
powsmooth[c].length = 100;
powsmooth[c].buf = calloc(powsmooth[c].length, sizeof (double));
powsmooth[c].start = 0;
powsmooth[c].n = 0;
}
winStart = 0;
winEnd = 0;
lastWindow = FALSE;
maxpow = 0;
do
{
winEnd = winStart + windowSize;
if (winEnd >= frameCount)
{
winEnd = frameCount;
lastWindow = TRUE;
}
afReadFrames(file, AF_DEFAULT_TRACK, frames, windowSize);
for (c=0; c<channelCount; c++)
{
sums[c] = 0;
for (i=0; i < winEnd - winStart; i++)
{
double sample;
sample = frames[i*channelCount + c];
sums[c] += sample*sample;
if (sample > maxSample)
maxSample = sample;
if (sample < minSample)
minSample = sample;
}
}
/* Compute power for each channel. */
for (c=0; c<channelCount; c++)
{
double pow;
int end;
pow = sums[c] / (winEnd - winStart);
end = (powsmooth[c].start + powsmooth[c].n) %
powsmooth[c].length;
powsmooth[c].buf[end] = pow;
if (powsmooth[c].n == powsmooth[c].length)
{
powsmooth[c].start = (powsmooth[c].start + 1) % powsmooth[c].length;
pow = get_smoothed_data(&powsmooth[c]);
if (pow > maxpow)
maxpow = pow;
}
else
{
powsmooth[c].n++;
}
}
winStart += windowSize;
} while (!lastWindow);
for (c = 0; c < channelCount; c++)
{
pow = get_smoothed_data(&powsmooth[c]);
if (pow > maxpow)
maxpow = pow;
}
free(sums);
free(frames);
for (c=0; c<channelCount; c++)
free(powsmooth[c].buf);
free(powsmooth);
level = sqrt(maxpow);
afCloseFile(file);
printf("file: %s\n", filename);
printf("level (dB): %f\n", 20 * log10(level));
printf("peak-: %f\n", minSample);
printf("peak+: %f\n", maxSample);
peak = fabs(minSample);
if (peak < fabs(maxSample))
peak = fabs(maxSample);
printf("peak (dB): %f\n", 20 * log10(peak));
}