233 lines
6.7 KiB
C
233 lines
6.7 KiB
C
/*
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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
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* License 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 GNU
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* 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
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/channel_layout.h"
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#include "libavutil/ffmath.h"
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#include "libavutil/opt.h"
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#include "avfilter.h"
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#include "audio.h"
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#include "formats.h"
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typedef struct ASubBoostContext {
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const AVClass *class;
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double dry_gain;
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double wet_gain;
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double feedback;
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double decay;
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double delay;
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double cutoff;
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double slope;
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double a0, a1, a2;
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double b0, b1, b2;
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int write_pos;
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int buffer_samples;
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AVFrame *i, *o;
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AVFrame *buffer;
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} ASubBoostContext;
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static int query_formats(AVFilterContext *ctx)
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{
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AVFilterFormats *formats = NULL;
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AVFilterChannelLayouts *layouts = NULL;
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static const enum AVSampleFormat sample_fmts[] = {
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AV_SAMPLE_FMT_DBLP,
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AV_SAMPLE_FMT_NONE
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};
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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_all_channel_counts();
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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_all_samplerates();
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return ff_set_common_samplerates(ctx, formats);
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}
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static int get_coeffs(AVFilterContext *ctx)
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{
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ASubBoostContext *s = ctx->priv;
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AVFilterLink *inlink = ctx->inputs[0];
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double w0 = 2 * M_PI * s->cutoff / inlink->sample_rate;
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double alpha = sin(w0) / 2 * sqrt(2. * (1. / s->slope - 1.) + 2.);
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s->a0 = 1 + alpha;
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s->a1 = -2 * cos(w0);
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s->a2 = 1 - alpha;
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s->b0 = (1 - cos(w0)) / 2;
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s->b1 = 1 - cos(w0);
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s->b2 = (1 - cos(w0)) / 2;
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s->a1 /= s->a0;
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s->a2 /= s->a0;
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s->b0 /= s->a0;
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s->b1 /= s->a0;
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s->b2 /= s->a0;
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s->buffer_samples = inlink->sample_rate * s->delay / 1000;
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return 0;
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}
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static int config_input(AVFilterLink *inlink)
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{
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AVFilterContext *ctx = inlink->dst;
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ASubBoostContext *s = ctx->priv;
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s->buffer = ff_get_audio_buffer(inlink, inlink->sample_rate / 10);
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s->i = ff_get_audio_buffer(inlink, 2);
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s->o = ff_get_audio_buffer(inlink, 2);
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if (!s->buffer || !s->i || !s->o)
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return AVERROR(ENOMEM);
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return get_coeffs(ctx);
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}
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static int filter_frame(AVFilterLink *inlink, AVFrame *in)
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{
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AVFilterContext *ctx = inlink->dst;
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AVFilterLink *outlink = ctx->outputs[0];
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ASubBoostContext *s = ctx->priv;
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const float wet = s->wet_gain, dry = s->dry_gain, feedback = s->feedback, decay = s->decay;
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int write_pos;
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AVFrame *out;
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if (av_frame_is_writable(in)) {
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out = in;
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} else {
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out = ff_get_audio_buffer(outlink, in->nb_samples);
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if (!out) {
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av_frame_free(&in);
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return AVERROR(ENOMEM);
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}
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av_frame_copy_props(out, in);
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}
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for (int ch = 0; ch < in->channels; ch++) {
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const double *src = (const double *)in->extended_data[ch];
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double *dst = (double *)out->extended_data[ch];
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double *buffer = (double *)s->buffer->extended_data[ch];
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double *ix = (double *)s->i->extended_data[ch];
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double *ox = (double *)s->o->extended_data[ch];
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write_pos = s->write_pos;
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for (int n = 0; n < in->nb_samples; n++) {
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double out_sample;
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out_sample = src[n] * s->b0 + ix[0] * s->b1 + ix[1] * s->b2 - ox[0] * s->a1 - ox[1] * s->a2;
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ix[1] = ix[0];
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ix[0] = src[n];
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ox[1] = ox[0];
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ox[0] = out_sample;
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buffer[write_pos] = buffer[write_pos] * decay + out_sample * feedback;
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dst[n] = src[n] * dry + buffer[write_pos] * wet;
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if (++write_pos >= s->buffer_samples)
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write_pos = 0;
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}
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}
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s->write_pos = write_pos;
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if (out != in)
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av_frame_free(&in);
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return ff_filter_frame(outlink, out);
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}
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static av_cold void uninit(AVFilterContext *ctx)
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{
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ASubBoostContext *s = ctx->priv;
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av_frame_free(&s->buffer);
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av_frame_free(&s->i);
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av_frame_free(&s->o);
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}
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static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
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char *res, int res_len, int flags)
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{
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int ret;
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ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
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if (ret < 0)
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return ret;
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return get_coeffs(ctx);
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}
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#define OFFSET(x) offsetof(ASubBoostContext, x)
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#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
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static const AVOption asubboost_options[] = {
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{ "dry", "set dry gain", OFFSET(dry_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS },
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{ "wet", "set wet gain", OFFSET(wet_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.8}, 0, 1, FLAGS },
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{ "decay", "set decay", OFFSET(decay), AV_OPT_TYPE_DOUBLE, {.dbl=0.7}, 0, 1, FLAGS },
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{ "feedback", "set feedback", OFFSET(feedback), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS },
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{ "cutoff", "set cutoff", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 50, 900, FLAGS },
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{ "slope", "set slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0.0001, 1, FLAGS },
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{ "delay", "set delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 1, 100, FLAGS },
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{ NULL }
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};
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AVFILTER_DEFINE_CLASS(asubboost);
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static const AVFilterPad inputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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.filter_frame = filter_frame,
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.config_props = config_input,
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},
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{ NULL }
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};
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static const AVFilterPad outputs[] = {
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{
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.name = "default",
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.type = AVMEDIA_TYPE_AUDIO,
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},
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{ NULL }
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};
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AVFilter ff_af_asubboost = {
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.name = "asubboost",
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.description = NULL_IF_CONFIG_SMALL("Boost subwoofer frequencies."),
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.query_formats = query_formats,
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.priv_size = sizeof(ASubBoostContext),
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.priv_class = &asubboost_class,
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.uninit = uninit,
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.inputs = inputs,
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.outputs = outputs,
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.process_command = process_command,
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};
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