libavfilter/asrc_sine.c - manifest_repos/ffmpeg - Git at Google

 /*
  * 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/eval.h"
 #include "libavutil/opt.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "internal.h"

 typedef struct SineContext {
     const AVClass *class;
     double frequency;
     double beep_factor;
     char *samples_per_frame;
     AVExpr *samples_per_frame_expr;
     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__)

 #define OPT_STR(name, field, def, min, max, descr, ...) \
     OPT_GENERIC(name, field, def, min, max, descr, STRING, 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 frequency factor",),
     OPT_DBL("b",                 beep_factor,            0, 0, DBL_MAX,   "set the beep frequency 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_STR("samples_per_frame", samples_per_frame, "1024", 0, 0,         "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 const char *const var_names[] = {
     "n",
     "pts",
     "t",
     "TB",
     NULL
 };

 enum {
     VAR_N,
     VAR_PTS,
     VAR_T,
     VAR_TB,
     VAR_VARS_NB
 };

 static av_cold int init(AVFilterContext *ctx)
 {
     int ret;
     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;
     }

     ret = av_expr_parse(&sine->samples_per_frame_expr,
                         sine->samples_per_frame, var_names,
                         NULL, NULL, NULL, NULL, 0, sine);
     if (ret < 0)
         return ret;

     return 0;
 }

 static av_cold void uninit(AVFilterContext *ctx)
 {
     SineContext *sine = ctx->priv;

     av_expr_free(sine->samples_per_frame_expr);
     sine->samples_per_frame_expr = NULL;
     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 };
     AVFilterFormats *formats;
     AVFilterChannelLayouts *layouts;
     int ret;

     formats = ff_make_format_list(sample_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
     ret = ff_set_common_formats (ctx, formats);
     if (ret < 0)
         return ret;

     layouts = ff_make_format64_list(chlayouts);
     if (!layouts)
         return AVERROR(ENOMEM);
     ret = ff_set_common_channel_layouts(ctx, layouts);
     if (ret < 0)
         return ret;

     formats = ff_make_format_list(sample_rates);
     if (!formats)
         return AVERROR(ENOMEM);
     return ff_set_common_samplerates(ctx, formats);
 }

 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;
     double values[VAR_VARS_NB] = {
         [VAR_N]   = outlink->frame_count_in,
         [VAR_PTS] = sine->pts,
         [VAR_T]   = sine->pts * av_q2d(outlink->time_base),
         [VAR_TB]  = av_q2d(outlink->time_base),
     };
     int i, nb_samples = lrint(av_expr_eval(sine->samples_per_frame_expr, values, sine));
     int16_t *samples;

     if (nb_samples <= 0) {
         av_log(sine, AV_LOG_WARNING, "nb samples expression evaluated to %d, "
                "defaulting to 1024\n", nb_samples);
         nb_samples = 1024;
     }

     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,
 };
	/*
	* 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/eval.h"
	#include "libavutil/opt.h"
	#include "audio.h"
	#include "avfilter.h"
	#include "internal.h"

	typedef struct SineContext {
	const AVClass *class;
	double frequency;
	double beep_factor;
	char *samples_per_frame;
	AVExpr *samples_per_frame_expr;
	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__)

	#define OPT_STR(name, field, def, min, max, descr, ...) \
	OPT_GENERIC(name, field, def, min, max, descr, STRING, 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 frequency factor",),
	OPT_DBL("b", beep_factor, 0, 0, DBL_MAX, "set the beep frequency 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_STR("samples_per_frame", samples_per_frame, "1024", 0, 0, "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(ia1) and v = exp(ia2), 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 const char *const var_names[] = {
	"n",
	"pts",
	"t",
	"TB",
	NULL
	};

	enum {
	VAR_N,
	VAR_PTS,
	VAR_T,
	VAR_TB,
	VAR_VARS_NB
	};

	static av_cold int init(AVFilterContext *ctx)
	{
	int ret;
	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;
	}

	ret = av_expr_parse(&sine->samples_per_frame_expr,
	sine->samples_per_frame, var_names,
	NULL, NULL, NULL, NULL, 0, sine);
	if (ret < 0)
	return ret;

	return 0;
	}

	static av_cold void uninit(AVFilterContext *ctx)
	{
	SineContext *sine = ctx->priv;

	av_expr_free(sine->samples_per_frame_expr);
	sine->samples_per_frame_expr = NULL;
	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 };
	AVFilterFormats *formats;
	AVFilterChannelLayouts *layouts;
	int ret;

	formats = ff_make_format_list(sample_fmts);
	if (!formats)
	return AVERROR(ENOMEM);
	ret = ff_set_common_formats (ctx, formats);
	if (ret < 0)
	return ret;

	layouts = ff_make_format64_list(chlayouts);
	if (!layouts)
	return AVERROR(ENOMEM);
	ret = ff_set_common_channel_layouts(ctx, layouts);
	if (ret < 0)
	return ret;

	formats = ff_make_format_list(sample_rates);
	if (!formats)
	return AVERROR(ENOMEM);
	return ff_set_common_samplerates(ctx, formats);
	}

	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;
	double values[VAR_VARS_NB] = {
	[VAR_N] = outlink->frame_count_in,
	[VAR_PTS] = sine->pts,
	[VAR_T] = sine->pts * av_q2d(outlink->time_base),
	[VAR_TB] = av_q2d(outlink->time_base),
	};
	int i, nb_samples = lrint(av_expr_eval(sine->samples_per_frame_expr, values, sine));
	int16_t *samples;

	if (nb_samples <= 0) {
	av_log(sine, AV_LOG_WARNING, "nb samples expression evaluated to %d, "
	"defaulting to 1024\n", nb_samples);
	nb_samples = 1024;
	}

	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,
	};