/* * 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/channel_layout.h" #include "libavutil/ffmath.h" #include "libavutil/opt.h" #include "avfilter.h" #include "audio.h" #include "formats.h" typedef struct ASubBoostContext { const AVClass *class; double dry_gain; double wet_gain; double feedback; double decay; double delay; double cutoff; double slope; double a0, a1, a2; double b0, b1, b2; int write_pos; int buffer_samples; AVFrame *i, *o; AVFrame *buffer; } ASubBoostContext; static int query_formats(AVFilterContext *ctx) { AVFilterFormats *formats = NULL; AVFilterChannelLayouts *layouts = NULL; static const enum AVSampleFormat sample_fmts[] = { AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE }; 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_all_channel_counts(); if (!layouts) return AVERROR(ENOMEM); ret = ff_set_common_channel_layouts(ctx, layouts); if (ret < 0) return ret; formats = ff_all_samplerates(); return ff_set_common_samplerates(ctx, formats); } static int get_coeffs(AVFilterContext *ctx) { ASubBoostContext *s = ctx->priv; AVFilterLink *inlink = ctx->inputs[0]; double w0 = 2 * M_PI * s->cutoff / inlink->sample_rate; double alpha = sin(w0) / 2 * sqrt(2. * (1. / s->slope - 1.) + 2.); s->a0 = 1 + alpha; s->a1 = -2 * cos(w0); s->a2 = 1 - alpha; s->b0 = (1 - cos(w0)) / 2; s->b1 = 1 - cos(w0); s->b2 = (1 - cos(w0)) / 2; s->a1 /= s->a0; s->a2 /= s->a0; s->b0 /= s->a0; s->b1 /= s->a0; s->b2 /= s->a0; s->buffer_samples = inlink->sample_rate * s->delay / 1000; return 0; } static int config_input(AVFilterLink *inlink) { AVFilterContext *ctx = inlink->dst; ASubBoostContext *s = ctx->priv; s->buffer = ff_get_audio_buffer(inlink, inlink->sample_rate / 10); s->i = ff_get_audio_buffer(inlink, 2); s->o = ff_get_audio_buffer(inlink, 2); if (!s->buffer || !s->i || !s->o) return AVERROR(ENOMEM); return get_coeffs(ctx); } static int filter_frame(AVFilterLink *inlink, AVFrame *in) { AVFilterContext *ctx = inlink->dst; AVFilterLink *outlink = ctx->outputs[0]; ASubBoostContext *s = ctx->priv; const float wet = s->wet_gain, dry = s->dry_gain, feedback = s->feedback, decay = s->decay; int write_pos; AVFrame *out; if (av_frame_is_writable(in)) { out = in; } else { 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 (int ch = 0; ch < in->channels; ch++) { const double *src = (const double *)in->extended_data[ch]; double *dst = (double *)out->extended_data[ch]; double *buffer = (double *)s->buffer->extended_data[ch]; double *ix = (double *)s->i->extended_data[ch]; double *ox = (double *)s->o->extended_data[ch]; write_pos = s->write_pos; for (int n = 0; n < in->nb_samples; n++) { double out_sample; out_sample = src[n] * s->b0 + ix[0] * s->b1 + ix[1] * s->b2 - ox[0] * s->a1 - ox[1] * s->a2; ix[1] = ix[0]; ix[0] = src[n]; ox[1] = ox[0]; ox[0] = out_sample; buffer[write_pos] = buffer[write_pos] * decay + out_sample * feedback; dst[n] = src[n] * dry + buffer[write_pos] * wet; if (++write_pos >= s->buffer_samples) write_pos = 0; } } s->write_pos = write_pos; if (out != in) av_frame_free(&in); return ff_filter_frame(outlink, out); } static av_cold void uninit(AVFilterContext *ctx) { ASubBoostContext *s = ctx->priv; av_frame_free(&s->buffer); av_frame_free(&s->i); av_frame_free(&s->o); } static int process_command(AVFilterContext *ctx, const char *cmd, const char *args, char *res, int res_len, int flags) { int ret; ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags); if (ret < 0) return ret; return get_coeffs(ctx); } #define OFFSET(x) offsetof(ASubBoostContext, x) #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM static const AVOption asubboost_options[] = { { "dry", "set dry gain", OFFSET(dry_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS }, { "wet", "set wet gain", OFFSET(wet_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0.8}, 0, 1, FLAGS }, { "decay", "set decay", OFFSET(decay), AV_OPT_TYPE_DOUBLE, {.dbl=0.7}, 0, 1, FLAGS }, { "feedback", "set feedback", OFFSET(feedback), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0, 1, FLAGS }, { "cutoff", "set cutoff", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=100}, 50, 900, FLAGS }, { "slope", "set slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0.0001, 1, FLAGS }, { "delay", "set delay", OFFSET(delay), AV_OPT_TYPE_DOUBLE, {.dbl=20}, 1, 100, FLAGS }, { NULL } }; AVFILTER_DEFINE_CLASS(asubboost); static const AVFilterPad inputs[] = { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, .filter_frame = filter_frame, .config_props = config_input, }, { NULL } }; static const AVFilterPad outputs[] = { { .name = "default", .type = AVMEDIA_TYPE_AUDIO, }, { NULL } }; AVFilter ff_af_asubboost = { .name = "asubboost", .description = NULL_IF_CONFIG_SMALL("Boost subwoofer frequencies."), .query_formats = query_formats, .priv_size = sizeof(ASubBoostContext), .priv_class = &asubboost_class, .uninit = uninit, .inputs = inputs, .outputs = outputs, .process_command = process_command, };