/* * Copyright (c) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Vladimir Sadovnikov and others * Copyright (c) 2015 Paul B Mahol * * 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/opt.h"#include "libavutil/samplefmt.h"#include "avfilter.h"#include "audio.h"#include "filters.h" typedef struct CompensationDelayContext {    const AVClass *class;    int distance_mm;    int distance_cm;    int distance_m;    double dry, wet;    int temp;     unsigned delay;    unsigned w_ptr;    unsigned buf_size;    AVFrame *delay_frame;} CompensationDelayContext; #define OFFSET(x) offsetof(CompensationDelayContext, x)#define A (AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM) static const AVOption compensationdelay_options[] = {    { "mm",   "set mm distance",    OFFSET(distance_mm), AV_OPT_TYPE_INT,    {.i64=0},    0,  10, A },    { "cm",   "set cm distance",    OFFSET(distance_cm), AV_OPT_TYPE_INT,    {.i64=0},    0, 100, A },    { "m",    "set meter distance", OFFSET(distance_m),  AV_OPT_TYPE_INT,    {.i64=0},    0, 100, A },    { "dry",  "set dry amount",     OFFSET(dry),         AV_OPT_TYPE_DOUBLE, {.dbl=0},    0,   1, A },    { "wet",  "set wet amount",     OFFSET(wet),         AV_OPT_TYPE_DOUBLE, {.dbl=1},    0,   1, A },    { "temp", "set temperature °C", OFFSET(temp),        AV_OPT_TYPE_INT,    {.i64=20}, -50,  50, A },    { NULL }}; AVFILTER_DEFINE_CLASS(compensationdelay); // The maximum distance for options#define COMP_DELAY_MAX_DISTANCE            (100.0 * 100.0 + 100.0 * 1.0 + 1.0)// The actual speed of sound in normal conditions#define COMP_DELAY_SOUND_SPEED_KM_H(temp)  1.85325 * (643.95 * sqrt(((temp + 273.15) / 273.15)))#define COMP_DELAY_SOUND_SPEED_CM_S(temp)  (COMP_DELAY_SOUND_SPEED_KM_H(temp) * (1000.0 * 100.0) /* cm/km */ / (60.0 * 60.0) /* s/h */)#define COMP_DELAY_SOUND_FRONT_DELAY(temp) (1.0 / COMP_DELAY_SOUND_SPEED_CM_S(temp))// The maximum delay may be reached by this filter#define COMP_DELAY_MAX_DELAY               (COMP_DELAY_MAX_DISTANCE * COMP_DELAY_SOUND_FRONT_DELAY(50)) static int config_input(AVFilterLink *inlink){    AVFilterContext *ctx = inlink->dst;    CompensationDelayContext *s = ctx->priv;    unsigned min_size, new_size = 1;     s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *               COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * inlink->sample_rate;    min_size = inlink->sample_rate * COMP_DELAY_MAX_DELAY;     while (new_size < min_size)        new_size <<= 1;     s->buf_size = new_size;    s->delay_frame = ff_get_audio_buffer(inlink, s->buf_size);    if (!s->delay_frame)        return AVERROR(ENOMEM);     return 0;} static int filter_frame(AVFilterLink *inlink, AVFrame *in){    AVFilterContext *ctx = inlink->dst;    AVFilterLink *outlink = ctx->outputs[0];    CompensationDelayContext *s = ctx->priv;    const unsigned b_mask = s->buf_size - 1;    const unsigned buf_size = s->buf_size;    const unsigned delay = s->delay;    const double dry = s->dry;    const double wet = s->wet;    unsigned r_ptr, w_ptr = 0;    AVFrame *out;    int n, ch;     out = ff_get_audio_buffer(outlink, in->nb_samples);    if (!out) {        av_frame_free(&in);        return AVERROR(ENOMEM);    }    av_frame_copy_props(out, in);     for (ch = 0; ch < inlink->ch_layout.nb_channels; ch++) {        const double *src = (const double *)in->extended_data[ch];        double *dst = (double *)out->extended_data[ch];        double *buffer = (double *)s->delay_frame->extended_data[ch];         w_ptr =  s->w_ptr;        r_ptr = (w_ptr + buf_size - delay) & b_mask;         for (n = 0; n < in->nb_samples; n++) {            const double sample = src[n];             buffer[w_ptr] = sample;            dst[n] = dry * sample + wet * buffer[r_ptr];            w_ptr = (w_ptr + 1) & b_mask;            r_ptr = (r_ptr + 1) & b_mask;        }    }    s->w_ptr = w_ptr;     if (ctx->is_disabled) {        av_frame_free(&out);        return ff_filter_frame(outlink, in);    }     av_frame_free(&in);    return ff_filter_frame(outlink, out);} static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,                           char *res, int res_len, int flags){    CompensationDelayContext *s = ctx->priv;    AVFilterLink *outlink = ctx->outputs[0];    int ret;     ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);    if (ret < 0)        return ret;     s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *               COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * outlink->sample_rate;     return 0;} static av_cold void uninit(AVFilterContext *ctx){    CompensationDelayContext *s = ctx->priv;     av_frame_free(&s->delay_frame);} static const AVFilterPad compensationdelay_inputs[] = {    {        .name         = "default",        .type         = AVMEDIA_TYPE_AUDIO,        .config_props = config_input,        .filter_frame = filter_frame,    },}; const FFFilter ff_af_compensationdelay = {    .p.name        = "compensationdelay",    .p.description = NULL_IF_CONFIG_SMALL("Audio Compensation Delay Line."),    .p.priv_class  = &compensationdelay_class,    .p.flags       = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,    .priv_size     = sizeof(CompensationDelayContext),    .uninit        = uninit,    FILTER_INPUTS(compensationdelay_inputs),    FILTER_OUTPUTS(ff_audio_default_filterpad),    FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),    .process_command = process_command,};