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-rw-r--r--libavfilter/asrc_sine.c223
1 files changed, 223 insertions, 0 deletions
diff --git a/libavfilter/asrc_sine.c b/libavfilter/asrc_sine.c
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+++ b/libavfilter/asrc_sine.c
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+/*
+ * 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 <float.h>
+
+#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, DBL_MAX, "set the sine frequency"),
+ OPT_DBL("f", frequency, 440, 0, DBL_MAX, "set the sine frequency"),
+ OPT_DBL("beep_factor", beep_factor, 0, 0, DBL_MAX, "set the beep fequency factor"),
+ OPT_DBL("b", beep_factor, 0, 0, DBL_MAX, "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)
+{
+ SineContext *sine = ctx->priv;
+
+ 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 ff_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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