From 21b092de7c1e2d7fae24ceca3aa2f8f9f1730cfc Mon Sep 17 00:00:00 2001 From: Nicolas George Date: Sat, 16 Mar 2013 16:33:05 +0100 Subject: lavfi: add sine audio source. --- libavfilter/asrc_sine.c | 228 ++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 228 insertions(+) create mode 100644 libavfilter/asrc_sine.c (limited to 'libavfilter/asrc_sine.c') diff --git a/libavfilter/asrc_sine.c b/libavfilter/asrc_sine.c new file mode 100644 index 0000000000..8b406ff455 --- /dev/null +++ b/libavfilter/asrc_sine.c @@ -0,0 +1,228 @@ +/* + * Copyright (c) 2013 Nicolas George + * + * This file is part of FFmpeg. + * + * FFmpeg is free software; you can redistribute it and/or + * modify it under the terms of the GNU Lesser General Public License + * as published by the Free Software Foundation; either + * version 2.1 of the License, or (at your option) any later version. + * + * FFmpeg 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser General Public License + * along with FFmpeg; if not, write to the Free Software Foundation, Inc., + * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libavutil/avassert.h" +#include "libavutil/channel_layout.h" +#include "libavutil/opt.h" +#include "audio.h" +#include "avfilter.h" +#include "internal.h" + +typedef struct { + const AVClass *class; + double frequency; + double beep_factor; + int samples_per_frame; + int sample_rate; + int64_t duration; + int16_t *sin; + int64_t pts; + uint32_t phi; ///< current phase of the sine (2pi = 1<<32) + uint32_t dphi; ///< phase increment between two samples + unsigned beep_period; + unsigned beep_index; + unsigned beep_length; + uint32_t phi_beep; ///< current phase of the beep + uint32_t dphi_beep; ///< phase increment of the beep +} SineContext; + +#define CONTEXT SineContext +#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM + +#define OPT_GENERIC(name, field, def, min, max, descr, type, deffield, ...) \ + { name, descr, offsetof(CONTEXT, field), AV_OPT_TYPE_ ## type, \ + { .deffield = def }, min, max, FLAGS, __VA_ARGS__ } + +#define OPT_INT(name, field, def, min, max, descr, ...) \ + OPT_GENERIC(name, field, def, min, max, descr, INT, i64, __VA_ARGS__) + +#define OPT_DBL(name, field, def, min, max, descr, ...) \ + OPT_GENERIC(name, field, def, min, max, descr, DOUBLE, dbl, __VA_ARGS__) + +#define OPT_DUR(name, field, def, min, max, descr, ...) \ + OPT_GENERIC(name, field, def, min, max, descr, DURATION, str, __VA_ARGS__) + +static const AVOption sine_options[] = { + OPT_DBL("frequency", frequency, 440, 0, INFINITY, "set the sine frequency"), + OPT_DBL("f", frequency, 440, 0, INFINITY, "set the sine frequency"), + OPT_DBL("beep_factor", beep_factor, 0, 0, INFINITY, "set the beep fequency factor"), + OPT_DBL("b", beep_factor, 0, 0, INFINITY, "set the beep fequency factor"), + OPT_INT("sample_rate", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), + OPT_INT("r", sample_rate, 44100, 1, INT_MAX, "set the sample rate"), + OPT_DUR("duration", duration, 0, 0, INT64_MAX, "set the audio duration"), + OPT_DUR("d", duration, 0, 0, INT64_MAX, "set the audio duration"), + OPT_INT("samples_per_frame", samples_per_frame, 1024, 0, INT_MAX, "set the number of samples per frame"), + {NULL}, +}; + +AVFILTER_DEFINE_CLASS(sine); + +#define LOG_PERIOD 15 +#define AMPLITUDE 4095 +#define AMPLITUDE_SHIFT 3 + +static void make_sin_table(int16_t *sin) +{ + unsigned half_pi = 1 << (LOG_PERIOD - 2); + unsigned ampls = AMPLITUDE << AMPLITUDE_SHIFT; + uint64_t unit2 = (uint64_t)(ampls * ampls) << 32; + unsigned step, i, c, s, k, new_k, n2; + + /* Principle: if u = exp(i*a1) and v = exp(i*a2), then + exp(i*(a1+a2)/2) = (u+v) / length(u+v) */ + sin[0] = 0; + sin[half_pi] = ampls; + for (step = half_pi; step > 1; step /= 2) { + /* k = (1 << 16) * amplitude / length(u+v) + In exact values, k is constant at a given step */ + k = 0x10000; + for (i = 0; i < half_pi / 2; i += step) { + s = sin[i] + sin[i + step]; + c = sin[half_pi - i] + sin[half_pi - i - step]; + n2 = s * s + c * c; + /* Newton's method to solve n² * k² = unit² */ + while (1) { + new_k = (k + unit2 / ((uint64_t)k * n2) + 1) >> 1; + if (k == new_k) + break; + k = new_k; + } + sin[i + step / 2] = (k * s + 0x7FFF) >> 16; + sin[half_pi - i - step / 2] = (k * c + 0x8000) >> 16; + } + } + /* Unshift amplitude */ + for (i = 0; i <= half_pi; i++) + sin[i] = (sin[i] + (1 << (AMPLITUDE_SHIFT - 1))) >> AMPLITUDE_SHIFT; + /* Use symmetries to fill the other three quarters */ + for (i = 0; i < half_pi; i++) + sin[half_pi * 2 - i] = sin[i]; + for (i = 0; i < 2 * half_pi; i++) + sin[i + 2 * half_pi] = -sin[i]; +} + +static av_cold int init(AVFilterContext *ctx, const char *args) +{ + SineContext *sine = ctx->priv; + static const char *shorthand[] = { "frequency", "beep_factor", NULL }; + int ret; + + sine->class = &sine_class; + av_opt_set_defaults(sine); + + if ((ret = av_opt_set_from_string(sine, args, shorthand, "=", ":")) < 0) + return ret; + if (!(sine->sin = av_malloc(sizeof(*sine->sin) << LOG_PERIOD))) + return AVERROR(ENOMEM); + sine->dphi = ldexp(sine->frequency, 32) / sine->sample_rate + 0.5; + make_sin_table(sine->sin); + + if (sine->beep_factor) { + sine->beep_period = sine->sample_rate; + sine->beep_length = sine->beep_period / 25; + sine->dphi_beep = ldexp(sine->beep_factor * sine->frequency, 32) / + sine->sample_rate + 0.5; + } + + return 0; +} + +static av_cold void uninit(AVFilterContext *ctx) +{ + SineContext *sine = ctx->priv; + + av_freep(&sine->sin); +} + +static av_cold int query_formats(AVFilterContext *ctx) +{ + SineContext *sine = ctx->priv; + static const int64_t chlayouts[] = { AV_CH_LAYOUT_MONO, -1 }; + int sample_rates[] = { sine->sample_rate, -1 }; + static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_S16, + AV_SAMPLE_FMT_NONE }; + + ff_set_common_formats (ctx, ff_make_format_list(sample_fmts)); + ff_set_common_channel_layouts(ctx, avfilter_make_format64_list(chlayouts)); + ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates)); + return 0; +} + +static av_cold int config_props(AVFilterLink *outlink) +{ + SineContext *sine = outlink->src->priv; + sine->duration = av_rescale(sine->duration, sine->sample_rate, AV_TIME_BASE); + return 0; +} + +static int request_frame(AVFilterLink *outlink) +{ + SineContext *sine = outlink->src->priv; + AVFrame *frame; + int i, nb_samples = sine->samples_per_frame; + int16_t *samples; + + if (sine->duration) { + nb_samples = FFMIN(nb_samples, sine->duration - sine->pts); + av_assert1(nb_samples >= 0); + if (!nb_samples) + return AVERROR_EOF; + } + if (!(frame = ff_get_audio_buffer(outlink, nb_samples))) + return AVERROR(ENOMEM); + samples = (int16_t *)frame->data[0]; + + for (i = 0; i < nb_samples; i++) { + samples[i] = sine->sin[sine->phi >> (32 - LOG_PERIOD)]; + sine->phi += sine->dphi; + if (sine->beep_index < sine->beep_length) { + samples[i] += sine->sin[sine->phi_beep >> (32 - LOG_PERIOD)] << 1; + sine->phi_beep += sine->dphi_beep; + } + if (++sine->beep_index == sine->beep_period) + sine->beep_index = 0; + } + + frame->pts = sine->pts; + sine->pts += nb_samples; + return ff_filter_frame(outlink, frame); +} + +static const AVFilterPad sine_outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .request_frame = request_frame, + .config_props = config_props, + }, + { NULL } +}; + +AVFilter avfilter_asrc_sine = { + .name = "sine", + .description = NULL_IF_CONFIG_SMALL("Generate sine wave audio signal."), + .query_formats = query_formats, + .init = init, + .uninit = uninit, + .priv_size = sizeof(SineContext), + .inputs = NULL, + .outputs = sine_outputs, + .priv_class = &sine_class, +}; 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