91 lines
2.2 KiB
C
91 lines
2.2 KiB
C
/*
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t16_8_short.c
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David Rowe
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19 August 2014
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Unit test for 16 <-> 8 kHz sample rate conversion functions. I
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evaluated output by plotting using Octave and looking for jaggies:
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pl("../unittest/out16_short.raw",1,3000)
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pl("../unittest/out8.raw",1,3000)
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Listening to it also shows up anything nasty:
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$ play -s -2 -r 16000 out16_short.raw
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$ play -s -2 -r 8000 out8.raw
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*/
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#include <assert.h>
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#include <math.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "codec2_fdmdv.h"
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#define N8 159 /* procssing buffer size at 8 kHz */
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#define N16 (N8 * FDMDV_OS)
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#define FRAMES 100
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#define TWO_PI 6.283185307
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#define FS 16000
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#define SINE
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int main() {
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short in8k_short[FDMDV_OS_TAPS_8K + N8];
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short out16k_short[N16];
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FILE *f16;
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short in16k_short[FDMDV_OS_TAPS_16K + N16];
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short out8k_short[N16];
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FILE *f8, *f8in;
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int i, f, t, t1;
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float freq = 800.0;
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f16 = fopen("out16_short.raw", "wb");
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assert(f16 != NULL);
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f8 = fopen("out8_short.raw", "wb");
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assert(f8 != NULL);
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f8in = fopen("in8_short.raw", "wb");
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assert(f8in != NULL);
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/* clear filter memories */
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for (i = 0; i < FDMDV_OS_TAPS_8K; i++) in8k_short[i] = 0;
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for (i = 0; i < FDMDV_OS_TAPS_16K; i++) in16k_short[i] = 0;
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t = t1 = 0;
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for (f = 0; f < FRAMES; f++) {
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#ifdef DC
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for (i = 0; i < N8; i++) in8k_short[FDMDV_OS_TAPS_8K + i] = 16000.0;
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#endif
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#ifdef SINE
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for (i = 0; i < N8; i++, t++)
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in8k_short[FDMDV_OS_TAPS_8K + i] = 8000.0 * cos(TWO_PI * t * freq / FS);
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#endif
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fwrite(in8k_short, sizeof(short), N8, f8in);
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/* upsample */
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fdmdv_8_to_16_short(out16k_short, &in8k_short[FDMDV_OS_TAPS_8K], N8);
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fwrite(out16k_short, sizeof(short), N16, f16);
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/* add a 6 kHz spurious signal for fun, we want down sampler to
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knock this out */
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for (i = 0; i < N16; i++, t1++)
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in16k_short[i + FDMDV_OS_TAPS_16K] =
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out16k_short[i] + 8000.0 * cos(TWO_PI * t1 * 6000.0 / FS);
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/* downsample */
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fdmdv_16_to_8_short(out8k_short, &in16k_short[FDMDV_OS_TAPS_16K], N8);
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/* save 8k to disk for plotting and check out */
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fwrite(out8k_short, sizeof(short), N8, f8);
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}
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fclose(f16);
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fclose(f8);
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fclose(f8in);
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return 0;
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}
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