forked from Mirrors/freeswitch
314ae8b6f3
git-svn-id: http://svn.freeswitch.org/svn/freeswitch/trunk@11535 d0543943-73ff-0310-b7d9-9358b9ac24b2
245 lines
8.0 KiB
C
245 lines
8.0 KiB
C
/*
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* SpanDSP - a series of DSP components for telephony
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*
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* noise_tests.c
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*
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* Written by Steve Underwood <steveu@coppice.org>
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*
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* Copyright (C) 2005 Steve Underwood
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*
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* All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*
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* $Id: noise_tests.c,v 1.17 2008/11/30 10:17:31 steveu Exp $
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*/
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/*! \page noise_tests_page Noise generator tests
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\section noise_tests_page_sec_1 What does it do?
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*/
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#if defined(HAVE_CONFIG_H)
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#include "config.h"
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#endif
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#include <stdlib.h>
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#include <stdio.h>
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#include <string.h>
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#include <audiofile.h>
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//#if defined(WITH_SPANDSP_INTERNALS)
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#define SPANDSP_EXPOSE_INTERNAL_STRUCTURES
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//#endif
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#include "spandsp.h"
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#include "spandsp-sim.h"
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#if !defined(M_PI)
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# define M_PI 3.14159265358979323846 /* pi */
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#endif
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#define OUT_FILE_NAME "noise.wav"
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/* Some simple sanity tests for the noise generation routines */
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int main (int argc, char *argv[])
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{
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int i;
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int j;
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int level;
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int clip_high;
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int clip_low;
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int quality;
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int total_samples;
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int seed = 1234567;
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int outframes;
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int16_t value;
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double total;
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double x;
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double p;
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double o;
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int bins[65536];
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int16_t amp[1024];
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noise_state_t noise_source;
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AFfilehandle outhandle;
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if ((outhandle = afOpenFile_telephony_write(OUT_FILE_NAME, 1)) == AF_NULL_FILEHANDLE)
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{
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fprintf(stderr, " Cannot create wave file '%s'\n", OUT_FILE_NAME);
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exit(2);
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}
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for (quality = 7; quality <= 20; quality += (20 - 7))
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{
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/* Generate AWGN at several RMS levels between -50dBOv and 0dBOv. Noise is
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generated for a large number of samples (1,000,000), and the RMS value
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of the noise is calculated along the way. If the resulting level is
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close to the requested RMS level, at least the scaling of the noise
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should be Ok. At high levels some clipping may distort the result a
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little. */
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printf("Testing AWGN power, with quality %d\n", quality);
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for (level = -50; level <= 0; level += 5)
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{
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clip_high = 0;
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clip_low = 0;
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total = 0.0;
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noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, quality);
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total_samples = 1000000;
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for (i = 0; i < total_samples; i++)
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{
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value = noise(&noise_source);
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if (value == 32767)
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clip_high++;
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else if (value == -32768)
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clip_low++;
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total += ((double) value)*((double) value);
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}
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printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
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log10(sqrt(total/total_samples)/32768.0)*20.0,
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level,
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100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
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clip_low,
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clip_high);
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if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
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{
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printf("Test failed\n");
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exit(2);
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}
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}
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}
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/* Now look at the statistical spread of the results, by collecting data in
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bins from a large number of samples. Use a fairly high noise level, but
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low enough to avoid significant clipping. Use the Gaussian model to
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predict the real probability, and present the results for graphing. */
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quality = 7;
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printf("Testing the statistical spread of AWGN, with quality %d\n", quality);
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memset(bins, 0, sizeof(bins));
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clip_high = 0;
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clip_low = 0;
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level = -15;
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noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_AWGN, quality);
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total_samples = 10000000;
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for (i = 0; i < total_samples; i++)
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{
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value = noise(&noise_source);
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if (value == 32767)
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clip_high++;
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else if (value == -32768)
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clip_low++;
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bins[value + 32768]++;
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}
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/* Find the RMS power level to expect */
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o = pow(10.0, level/20.0)*(32768.0*0.70711);
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for (i = 0; i < 65536 - 10; i++)
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{
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x = i - 32768;
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/* Find the real probability for this bin */
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p = (1.0/(o*sqrt(2.0*M_PI)))*exp(-(x*x)/(2.0*o*o));
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/* Now do a little smoothing on the real data to get a reasonably
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steady answer */
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x = 0;
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for (j = 0; j < 10; j++)
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x += bins[i + j];
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x /= 10.0;
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x /= total_samples;
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/* Now send it out for graphing. */
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if (p > 0.0000001)
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printf("%6d %.7f %.7f\n", i - 32768, x, p);
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}
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printf("Generating AWGN at -15dBOv to file\n");
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for (j = 0; j < 50; j++)
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{
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for (i = 0; i < 1024; i++)
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amp[i] = noise(&noise_source);
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outframes = afWriteFrames(outhandle,
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AF_DEFAULT_TRACK,
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amp,
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1024);
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if (outframes != 1024)
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{
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fprintf(stderr, " Error writing wave file\n");
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exit(2);
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}
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}
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/* Generate Hoth noise at several RMS levels between -50dBm and 0dBm. Noise
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is generated for a large number of samples (1,000,000), and the RMS value
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of the noise is calculated along the way. If the resulting level is
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close to the requested RMS level, at least the scaling of the noise
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should be Ok. At high levels some clipping may distort the result a
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little. */
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quality = 7;
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printf("Testing Hoth noise power, with quality %d\n", quality);
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for (level = -50; level <= 0; level += 5)
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{
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clip_high = 0;
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clip_low = 0;
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total = 0.0;
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noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, quality);
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total_samples = 1000000;
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for (i = 0; i < total_samples; i++)
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{
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value = noise(&noise_source);
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if (value == 32767)
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clip_high++;
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else if (value == -32768)
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clip_low++;
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total += ((double) value)*((double) value);
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}
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printf ("RMS = %.3f (expected %d) %.2f%% error [clipped samples %d+%d]\n",
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log10(sqrt(total/total_samples)/32768.0)*20.0,
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level,
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100.0*(1.0 - sqrt(total/total_samples)/(pow(10.0, level/20.0)*32768.0)),
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clip_low,
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clip_high);
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if (level < -5 && fabs(log10(sqrt(total/total_samples)/32768.0)*20.0 - level) > 0.2)
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{
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printf("Test failed\n");
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exit(2);
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}
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}
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quality = 7;
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printf("Generating Hoth noise at -15dBOv to file\n");
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level = -15;
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noise_init_dbov(&noise_source, seed, (float) level, NOISE_CLASS_HOTH, quality);
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for (j = 0; j < 50; j++)
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{
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for (i = 0; i < 1024; i++)
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amp[i] = noise(&noise_source);
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outframes = afWriteFrames(outhandle,
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AF_DEFAULT_TRACK,
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amp,
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1024);
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if (outframes != 1024)
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{
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fprintf(stderr, " Error writing wave file\n");
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exit(2);
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}
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}
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if (afCloseFile(outhandle))
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{
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fprintf(stderr, " Cannot close wave file '%s'\n", OUT_FILE_NAME);
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exit(2);
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}
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printf("Tests passed.\n");
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return 0;
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}
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/*- End of function --------------------------------------------------------*/
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/*- End of file ------------------------------------------------------------*/
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