GCC Code Coverage Report
Directory: ../../../ffmpeg/ Exec Total Coverage
File: src/libavfilter/asrc_sine.c Lines: 89 99 89.9 %
Date: 2020-08-13 15:06:06 Branches: 32 42 76.2 %

Line Branch Exec Source
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/*
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 * Copyright (c) 2013 Nicolas George
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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 License
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 * 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
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 * GNU 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 License
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 * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
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 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include <float.h>
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#include "libavutil/avassert.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/eval.h"
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#include "libavutil/opt.h"
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#include "audio.h"
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#include "avfilter.h"
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#include "internal.h"
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typedef struct SineContext {
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    const AVClass *class;
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    double frequency;
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    double beep_factor;
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    char *samples_per_frame;
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    AVExpr *samples_per_frame_expr;
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    int sample_rate;
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    int64_t duration;
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    int16_t *sin;
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    int64_t pts;
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    uint32_t phi;  ///< current phase of the sine (2pi = 1<<32)
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    uint32_t dphi; ///< phase increment between two samples
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    unsigned beep_period;
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    unsigned beep_index;
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    unsigned beep_length;
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    uint32_t phi_beep;  ///< current phase of the beep
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    uint32_t dphi_beep; ///< phase increment of the beep
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} SineContext;
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#define CONTEXT SineContext
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#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
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#define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \
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    { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type,          \
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      { .deffield = def }, min, max, FLAGS, __VA_ARGS__ }
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#define OPT_INT(name, field, def, min, max, descr, ...) \
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    OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__)
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#define OPT_DBL(name, field, def, min, max, descr, ...) \
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    OPT_GENERIC(name, field, def, min, max, descr, DOUBLE, dbl, __VA_ARGS__)
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#define OPT_DUR(name, field, def, min, max, descr, ...) \
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    OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__)
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#define OPT_STR(name, field, def, min, max, descr, ...) \
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    OPT_GENERIC(name, field, def, min, max, descr, STRING, str, __VA_ARGS__)
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static const AVOption sine_options[] = {
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    OPT_DBL("frequency",         frequency,            440, 0, DBL_MAX,   "set the sine frequency",),
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    OPT_DBL("f",                 frequency,            440, 0, DBL_MAX,   "set the sine frequency",),
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    OPT_DBL("beep_factor",       beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),
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    OPT_DBL("b",                 beep_factor,            0, 0, DBL_MAX,   "set the beep frequency factor",),
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    OPT_INT("sample_rate",       sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),
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    OPT_INT("r",                 sample_rate,        44100, 1, INT_MAX,   "set the sample rate",),
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    OPT_DUR("duration",          duration,               0, 0, INT64_MAX, "set the audio duration",),
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    OPT_DUR("d",                 duration,               0, 0, INT64_MAX, "set the audio duration",),
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    OPT_STR("samples_per_frame", samples_per_frame, "1024", 0, 0,         "set the number of samples per frame",),
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    {NULL}
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};
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AVFILTER_DEFINE_CLASS(sine);
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#define LOG_PERIOD 15
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#define AMPLITUDE 4095
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#define AMPLITUDE_SHIFT 3
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static void make_sin_table(int16_t *sin)
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{
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    unsigned half_pi = 1 << (LOG_PERIOD - 2);
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    unsigned ampls = AMPLITUDE << AMPLITUDE_SHIFT;
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    uint64_t unit2 = (uint64_t)(ampls * ampls) << 32;
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    unsigned step, i, c, s, k, new_k, n2;
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    /* Principle: if u = exp(i*a1) and v = exp(i*a2), then
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       exp(i*(a1+a2)/2) = (u+v) / length(u+v) */
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    sin[0] = 0;
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    sin[half_pi] = ampls;
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    for (step = half_pi; step > 1; step /= 2) {
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        /* k = (1 << 16) * amplitude / length(u+v)
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           In exact values, k is constant at a given step */
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        k = 0x10000;
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53417
        for (i = 0; i < half_pi / 2; i += step) {
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53248
            s = sin[i] + sin[i + step];
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53248
            c = sin[half_pi - i] + sin[half_pi - i - step];
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53248
            n2 = s * s + c * c;
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            /* Newton's method to solve n² * k² = unit² */
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            while (1) {
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62192
                new_k = (k + unit2 / ((uint64_t)k * n2) + 1) >> 1;
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62192
                if (k == new_k)
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53248
                    break;
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                k = new_k;
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            }
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            sin[i + step / 2] = (k * s + 0x7FFF) >> 16;
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            sin[half_pi - i - step / 2] = (k * c + 0x8000) >> 16;
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        }
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    }
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    /* Unshift amplitude */
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    for (i = 0; i <= half_pi; i++)
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        sin[i] = (sin[i] + (1 << (AMPLITUDE_SHIFT - 1))) >> AMPLITUDE_SHIFT;
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    /* Use symmetries to fill the other three quarters */
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    for (i = 0; i < half_pi; i++)
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        sin[half_pi * 2 - i] = sin[i];
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    for (i = 0; i < 2 * half_pi; i++)
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212992
        sin[i + 2 * half_pi] = -sin[i];
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}
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static const char *const var_names[] = {
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    "n",
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    "pts",
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    "t",
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    "TB",
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    NULL
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};
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enum {
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    VAR_N,
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    VAR_PTS,
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    VAR_T,
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    VAR_TB,
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    VAR_VARS_NB
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};
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static av_cold int init(AVFilterContext *ctx)
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{
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    int ret;
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    SineContext *sine = ctx->priv;
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    if (!(sine->sin = av_malloc(sizeof(*sine->sin) << LOG_PERIOD)))
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        return AVERROR(ENOMEM);
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    sine->dphi = ldexp(sine->frequency, 32) / sine->sample_rate + 0.5;
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    make_sin_table(sine->sin);
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    if (sine->beep_factor) {
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        sine->beep_period = sine->sample_rate;
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        sine->beep_length = sine->beep_period / 25;
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        sine->dphi_beep = ldexp(sine->beep_factor * sine->frequency, 32) /
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                          sine->sample_rate + 0.5;
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    }
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    ret = av_expr_parse(&sine->samples_per_frame_expr,
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                        sine->samples_per_frame, var_names,
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                        NULL, NULL, NULL, NULL, 0, sine);
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    if (ret < 0)
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        return ret;
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    return 0;
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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    SineContext *sine = ctx->priv;
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    av_expr_free(sine->samples_per_frame_expr);
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    sine->samples_per_frame_expr = NULL;
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    av_freep(&sine->sin);
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}
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static av_cold int query_formats(AVFilterContext *ctx)
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{
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    SineContext *sine = ctx->priv;
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    static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 };
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    int sample_rates[] = { sine->sample_rate, -1 };
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    static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16,
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                                                       AV_SAMPLE_FMT_NONE };
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    AVFilterFormats *formats;
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    AVFilterChannelLayouts *layouts;
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    int ret;
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    formats = ff_make_format_list(sample_fmts);
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    if (!formats)
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        return AVERROR(ENOMEM);
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    ret = ff_set_common_formats (ctx, formats);
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    if (ret < 0)
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        return ret;
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    layouts = ff_make_format64_list(chlayouts);
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    if (!layouts)
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        return AVERROR(ENOMEM);
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    ret = ff_set_common_channel_layouts(ctx, layouts);
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    if (ret < 0)
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        return ret;
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    formats = ff_make_format_list(sample_rates);
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    if (!formats)
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        return AVERROR(ENOMEM);
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    return ff_set_common_samplerates(ctx, formats);
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}
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static av_cold int config_props(AVFilterLink *outlink)
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{
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    SineContext *sine = outlink->src->priv;
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    sine->duration = av_rescale(sine->duration, sine->sample_rate, AV_TIME_BASE);
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    return 0;
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}
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static int request_frame(AVFilterLink *outlink)
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{
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    SineContext *sine = outlink->src->priv;
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    AVFrame *frame;
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    double values[VAR_VARS_NB] = {
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        [VAR_N]   = outlink->frame_count_in,
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        [VAR_PTS] = sine->pts,
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        [VAR_T]   = sine->pts * av_q2d(outlink->time_base),
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        [VAR_TB]  = av_q2d(outlink->time_base),
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    };
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    int i, nb_samples = lrint(av_expr_eval(sine->samples_per_frame_expr, values, sine));
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    int16_t *samples;
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    if (nb_samples <= 0) {
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        av_log(sine, AV_LOG_WARNING, "nb samples expression evaluated to %d, "
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               "defaulting to 1024\n", nb_samples);
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        nb_samples = 1024;
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    }
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    if (sine->duration) {
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        nb_samples = FFMIN(nb_samples, sine->duration - sine->pts);
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        av_assert1(nb_samples >= 0);
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        if (!nb_samples)
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            return AVERROR_EOF;
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    }
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    if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
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        return AVERROR(ENOMEM);
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    samples = (int16_t *)frame->data[0];
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401197
    for (i = 0; i < nb_samples; i++) {
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400800
        samples[i] = sine->sin[sine->phi >> (32 - LOG_PERIOD)];
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400800
        sine->phi += sine->dphi;
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400800
        if (sine->beep_index < sine->beep_length) {
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            samples[i] += sine->sin[sine->phi_beep >> (32 - LOG_PERIOD)] << 1;
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14112
            sine->phi_beep += sine->dphi_beep;
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        }
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400800
        if (++sine->beep_index == sine->beep_period)
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            sine->beep_index = 0;
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    }
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    frame->pts = sine->pts;
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    sine->pts += nb_samples;
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    return ff_filter_frame(outlink, frame);
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}
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static const AVFilterPad sine_outputs[] = {
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    {
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        .name          = "default",
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        .type          = AVMEDIA_TYPE_AUDIO,
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        .request_frame = request_frame,
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        .config_props  = config_props,
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    },
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    { NULL }
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};
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AVFilter ff_asrc_sine = {
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    .name          = "sine",
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    .description   = NULL_IF_CONFIG_SMALL("Generate sine wave audio signal."),
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    .query_formats = query_formats,
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    .init          = init,
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    .uninit        = uninit,
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    .priv_size     = sizeof(SineContext),
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    .inputs        = NULL,
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    .outputs       = sine_outputs,
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    .priv_class    = &sine_class,
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};