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ffmpeg / tests / audiogen.c @ 3a74415d

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/*
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 * Generates a synthetic stereo sound
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 * NOTE: no floats are used to guaranty a bit exact output.
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 *
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 * Copyright (c) 2002 Fabrice Bellard
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg 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 GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <stdlib.h>
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#include <stdio.h>
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#define NB_CHANNELS 2
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#define FE 44100
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static unsigned int myrnd(unsigned int *seed_ptr, int n)
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{
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    unsigned int seed, val;
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    seed = *seed_ptr;
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    seed = (seed * 314159) + 1;
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    if (n == 256) {
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        val = seed >> 24;
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    } else {
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        val = seed % n;
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    }
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    *seed_ptr = seed;
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    return val;
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}
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#define FRAC_BITS 16
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#define FRAC_ONE (1 << FRAC_BITS)
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#define COS_TABLE_BITS 7
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/* integer cosinus */
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static const unsigned short cos_table[(1 << COS_TABLE_BITS) + 2] = {
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 0x8000, 0x7ffe, 0x7ff6, 0x7fea, 0x7fd9, 0x7fc2, 0x7fa7, 0x7f87,
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 0x7f62, 0x7f38, 0x7f0a, 0x7ed6, 0x7e9d, 0x7e60, 0x7e1e, 0x7dd6,
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 0x7d8a, 0x7d3a, 0x7ce4, 0x7c89, 0x7c2a, 0x7bc6, 0x7b5d, 0x7aef,
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 0x7a7d, 0x7a06, 0x798a, 0x790a, 0x7885, 0x77fb, 0x776c, 0x76d9,
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 0x7642, 0x75a6, 0x7505, 0x7460, 0x73b6, 0x7308, 0x7255, 0x719e,
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 0x70e3, 0x7023, 0x6f5f, 0x6e97, 0x6dca, 0x6cf9, 0x6c24, 0x6b4b,
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 0x6a6e, 0x698c, 0x68a7, 0x67bd, 0x66d0, 0x65de, 0x64e9, 0x63ef,
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 0x62f2, 0x61f1, 0x60ec, 0x5fe4, 0x5ed7, 0x5dc8, 0x5cb4, 0x5b9d,
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 0x5a82, 0x5964, 0x5843, 0x571e, 0x55f6, 0x54ca, 0x539b, 0x5269,
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 0x5134, 0x4ffb, 0x4ec0, 0x4d81, 0x4c40, 0x4afb, 0x49b4, 0x486a,
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 0x471d, 0x45cd, 0x447b, 0x4326, 0x41ce, 0x4074, 0x3f17, 0x3db8,
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 0x3c57, 0x3af3, 0x398d, 0x3825, 0x36ba, 0x354e, 0x33df, 0x326e,
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 0x30fc, 0x2f87, 0x2e11, 0x2c99, 0x2b1f, 0x29a4, 0x2827, 0x26a8,
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 0x2528, 0x23a7, 0x2224, 0x209f, 0x1f1a, 0x1d93, 0x1c0c, 0x1a83,
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 0x18f9, 0x176e, 0x15e2, 0x1455, 0x12c8, 0x113a, 0x0fab, 0x0e1c,
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 0x0c8c, 0x0afb, 0x096b, 0x07d9, 0x0648, 0x04b6, 0x0324, 0x0192,
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 0x0000, 0x0000,
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};
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#define CSHIFT (FRAC_BITS - COS_TABLE_BITS - 2)
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static int int_cos(int a)
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{
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    int neg, v, f;
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    const unsigned short *p;
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    a = a & (FRAC_ONE - 1); /* modulo 2 * pi */
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    if (a >= (FRAC_ONE / 2))
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        a = FRAC_ONE - a;
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    neg = 0;
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    if (a > (FRAC_ONE / 4)) {
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        neg = -1;
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        a = (FRAC_ONE / 2) - a;
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    }
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    p = cos_table + (a >> CSHIFT);
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    /* linear interpolation */
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    f = a & ((1 << CSHIFT) - 1);
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    v = p[0] + (((p[1] - p[0]) * f + (1 << (CSHIFT - 1))) >> CSHIFT);
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    v = (v ^ neg) - neg;
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    v = v << (FRAC_BITS - 15);
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    return v;
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}
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FILE *outfile;
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void put_sample(int v)
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{
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    fputc(v & 0xff, outfile);
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    fputc((v >> 8) & 0xff, outfile);
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}
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int main(int argc, char **argv)
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{
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    int i, a, v, j, f, amp, ampa;
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    unsigned int seed = 1;
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    int tabf1[NB_CHANNELS], tabf2[NB_CHANNELS];
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    int taba[NB_CHANNELS];
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    if (argc != 2) {
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        printf("usage: %s file\n"
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               "generate a test raw 16 bit stereo audio stream\n", argv[0]);
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        exit(1);
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    }
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    outfile = fopen(argv[1], "wb");
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    if (!outfile) {
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        perror(argv[1]);
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        return 1;
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    }
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    /* 1 second of single freq sinus at 1000 Hz */
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    a = 0;
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    for(i=0;i<1 * FE;i++) {
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        v = (int_cos(a) * 10000) >> FRAC_BITS;
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        for(j=0;j<NB_CHANNELS;j++)
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            put_sample(v);
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        a += (1000 * FRAC_ONE) / FE;
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    }
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    /* 1 second of varing frequency between 100 and 10000 Hz */
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    a = 0;
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    for(i=0;i<1 * FE;i++) {
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        v = (int_cos(a) * 10000) >> FRAC_BITS;
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        for(j=0;j<NB_CHANNELS;j++)
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            put_sample(v);
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        f = 100 + (((10000 - 100) * i) / FE);
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        a += (f * FRAC_ONE) / FE;
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    }
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    /* 0.5 second of low amplitude white noise */
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    for(i=0;i<FE / 2;i++) {
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        v = myrnd(&seed, 20000) - 10000;
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        for(j=0;j<NB_CHANNELS;j++)
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            put_sample(v);
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    }
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    /* 0.5 second of high amplitude white noise */
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    for(i=0;i<FE / 2;i++) {
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        v = myrnd(&seed, 65535) - 32768;
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        for(j=0;j<NB_CHANNELS;j++)
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            put_sample(v);
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    }
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    /* stereo : 2 unrelated ramps */
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    for(j=0;j<NB_CHANNELS;j++) {
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        taba[j] = 0;
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        tabf1[j] = 100 + myrnd(&seed, 5000);
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        tabf2[j] = 100 + myrnd(&seed, 5000);
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    }
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    for(i=0;i<1 * FE;i++) {
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        for(j=0;j<NB_CHANNELS;j++) {
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            v = (int_cos(taba[j]) * 10000) >> FRAC_BITS;
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            put_sample(v);
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            f = tabf1[j] + (((tabf2[j] - tabf1[j]) * i) / FE);
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            taba[j] += (f * FRAC_ONE) / FE;
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        }
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    }
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    /* stereo 500 Hz with varying volume */
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    a = 0;
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    ampa = 0;
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    for(i=0;i<2 * FE;i++) {
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        for(j=0;j<NB_CHANNELS;j++) {
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            amp = ((FRAC_ONE + int_cos(ampa)) * 5000) >> FRAC_BITS;
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            if (j & 1)
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                amp = 10000 - amp;
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            v = (int_cos(a) * amp) >> FRAC_BITS;
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            put_sample(v);
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            a += (500 * FRAC_ONE) / FE;
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            ampa += (2 * FRAC_ONE) / FE;
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        }
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    }
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    fclose(outfile);
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    return 0;
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}