| /* |
| * 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 |
| */ |
| |
| /** |
| * @file |
| * Crossover filter |
| * |
| * Split an audio stream into several bands. |
| */ |
| |
| #include "libavutil/attributes.h" |
| #include "libavutil/avstring.h" |
| #include "libavutil/channel_layout.h" |
| #include "libavutil/eval.h" |
| #include "libavutil/internal.h" |
| #include "libavutil/opt.h" |
| |
| #include "audio.h" |
| #include "avfilter.h" |
| #include "formats.h" |
| #include "internal.h" |
| |
| #define MAX_SPLITS 16 |
| #define MAX_BANDS MAX_SPLITS + 1 |
| |
| typedef struct BiquadContext { |
| double a0, a1, a2; |
| double b1, b2; |
| double i1, i2; |
| double o1, o2; |
| } BiquadContext; |
| |
| typedef struct CrossoverChannel { |
| BiquadContext lp[MAX_BANDS][4]; |
| BiquadContext hp[MAX_BANDS][4]; |
| } CrossoverChannel; |
| |
| typedef struct AudioCrossoverContext { |
| const AVClass *class; |
| |
| char *splits_str; |
| int order; |
| |
| int filter_count; |
| int nb_splits; |
| float *splits; |
| |
| CrossoverChannel *xover; |
| |
| AVFrame *input_frame; |
| AVFrame *frames[MAX_BANDS]; |
| } AudioCrossoverContext; |
| |
| #define OFFSET(x) offsetof(AudioCrossoverContext, x) |
| #define AF AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_FILTERING_PARAM |
| |
| static const AVOption acrossover_options[] = { |
| { "split", "set split frequencies", OFFSET(splits_str), AV_OPT_TYPE_STRING, {.str="500"}, 0, 0, AF }, |
| { "order", "set order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=1}, 0, 2, AF, "m" }, |
| { "2nd", "2nd order", 0, AV_OPT_TYPE_CONST, {.i64=0}, 0, 0, AF, "m" }, |
| { "4th", "4th order", 0, AV_OPT_TYPE_CONST, {.i64=1}, 0, 0, AF, "m" }, |
| { "8th", "8th order", 0, AV_OPT_TYPE_CONST, {.i64=2}, 0, 0, AF, "m" }, |
| { NULL } |
| }; |
| |
| AVFILTER_DEFINE_CLASS(acrossover); |
| |
| static av_cold int init(AVFilterContext *ctx) |
| { |
| AudioCrossoverContext *s = ctx->priv; |
| char *p, *arg, *saveptr = NULL; |
| int i, ret = 0; |
| |
| s->splits = av_calloc(MAX_SPLITS, sizeof(*s->splits)); |
| if (!s->splits) |
| return AVERROR(ENOMEM); |
| |
| p = s->splits_str; |
| for (i = 0; i < MAX_SPLITS; i++) { |
| float freq; |
| |
| if (!(arg = av_strtok(p, " |", &saveptr))) |
| break; |
| |
| p = NULL; |
| |
| if (av_sscanf(arg, "%f", &freq) != 1) { |
| av_log(ctx, AV_LOG_ERROR, "Invalid syntax for frequency[%d].\n", i); |
| return AVERROR(EINVAL); |
| } |
| if (freq <= 0) { |
| av_log(ctx, AV_LOG_ERROR, "Frequency %f must be positive number.\n", freq); |
| return AVERROR(EINVAL); |
| } |
| |
| if (i > 0 && freq <= s->splits[i-1]) { |
| av_log(ctx, AV_LOG_ERROR, "Frequency %f must be in increasing order.\n", freq); |
| return AVERROR(EINVAL); |
| } |
| |
| s->splits[i] = freq; |
| } |
| |
| s->nb_splits = i; |
| |
| for (i = 0; i <= s->nb_splits; i++) { |
| AVFilterPad pad = { 0 }; |
| char *name; |
| |
| pad.type = AVMEDIA_TYPE_AUDIO; |
| name = av_asprintf("out%d", ctx->nb_outputs); |
| if (!name) |
| return AVERROR(ENOMEM); |
| pad.name = name; |
| |
| if ((ret = ff_insert_outpad(ctx, i, &pad)) < 0) { |
| av_freep(&pad.name); |
| return ret; |
| } |
| } |
| |
| return ret; |
| } |
| |
| static void set_lp(BiquadContext *b, double fc, double q, double sr) |
| { |
| double omega = 2.0 * M_PI * fc / sr; |
| double sn = sin(omega); |
| double cs = cos(omega); |
| double alpha = sn / (2. * q); |
| double inv = 1.0 / (1.0 + alpha); |
| |
| b->a0 = (1. - cs) * 0.5 * inv; |
| b->a1 = (1. - cs) * inv; |
| b->a2 = b->a0; |
| b->b1 = -2. * cs * inv; |
| b->b2 = (1. - alpha) * inv; |
| } |
| |
| static void set_hp(BiquadContext *b, double fc, double q, double sr) |
| { |
| double omega = 2 * M_PI * fc / sr; |
| double sn = sin(omega); |
| double cs = cos(omega); |
| double alpha = sn / (2 * q); |
| double inv = 1.0 / (1.0 + alpha); |
| |
| b->a0 = inv * (1. + cs) / 2.; |
| b->a1 = -2. * b->a0; |
| b->a2 = b->a0; |
| b->b1 = -2. * cs * inv; |
| b->b2 = (1. - alpha) * inv; |
| } |
| |
| static int config_input(AVFilterLink *inlink) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| AudioCrossoverContext *s = ctx->priv; |
| int ch, band, sample_rate = inlink->sample_rate; |
| double q; |
| |
| s->xover = av_calloc(inlink->channels, sizeof(*s->xover)); |
| if (!s->xover) |
| return AVERROR(ENOMEM); |
| |
| switch (s->order) { |
| case 0: |
| q = 0.5; |
| s->filter_count = 1; |
| break; |
| case 1: |
| q = M_SQRT1_2; |
| s->filter_count = 2; |
| break; |
| case 2: |
| q = 0.54; |
| s->filter_count = 4; |
| break; |
| } |
| |
| for (ch = 0; ch < inlink->channels; ch++) { |
| for (band = 0; band <= s->nb_splits; band++) { |
| set_lp(&s->xover[ch].lp[band][0], s->splits[band], q, sample_rate); |
| set_hp(&s->xover[ch].hp[band][0], s->splits[band], q, sample_rate); |
| |
| if (s->order > 1) { |
| set_lp(&s->xover[ch].lp[band][1], s->splits[band], 1.34, sample_rate); |
| set_hp(&s->xover[ch].hp[band][1], s->splits[band], 1.34, sample_rate); |
| set_lp(&s->xover[ch].lp[band][2], s->splits[band], q, sample_rate); |
| set_hp(&s->xover[ch].hp[band][2], s->splits[band], q, sample_rate); |
| set_lp(&s->xover[ch].lp[band][3], s->splits[band], 1.34, sample_rate); |
| set_hp(&s->xover[ch].hp[band][3], s->splits[band], 1.34, sample_rate); |
| } else { |
| set_lp(&s->xover[ch].lp[band][1], s->splits[band], q, sample_rate); |
| set_hp(&s->xover[ch].hp[band][1], s->splits[band], q, sample_rate); |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int query_formats(AVFilterContext *ctx) |
| { |
| AVFilterFormats *formats; |
| AVFilterChannelLayouts *layouts; |
| static const enum AVSampleFormat sample_fmts[] = { |
| AV_SAMPLE_FMT_DBLP, |
| AV_SAMPLE_FMT_NONE |
| }; |
| int 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_make_format_list(sample_fmts); |
| if (!formats) |
| return AVERROR(ENOMEM); |
| ret = ff_set_common_formats(ctx, formats); |
| if (ret < 0) |
| return ret; |
| |
| formats = ff_all_samplerates(); |
| if (!formats) |
| return AVERROR(ENOMEM); |
| return ff_set_common_samplerates(ctx, formats); |
| } |
| |
| static double biquad_process(BiquadContext *b, double in) |
| { |
| double out = in * b->a0 + b->i1 * b->a1 + b->i2 * b->a2 - b->o1 * b->b1 - b->o2 * b->b2; |
| |
| b->i2 = b->i1; |
| b->o2 = b->o1; |
| b->i1 = in; |
| b->o1 = out; |
| |
| return out; |
| } |
| |
| static int filter_channels(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs) |
| { |
| AudioCrossoverContext *s = ctx->priv; |
| AVFrame *in = s->input_frame; |
| AVFrame **frames = s->frames; |
| const int start = (in->channels * jobnr) / nb_jobs; |
| const int end = (in->channels * (jobnr+1)) / nb_jobs; |
| int f, band; |
| |
| for (int ch = start; ch < end; ch++) { |
| const double *src = (const double *)in->extended_data[ch]; |
| CrossoverChannel *xover = &s->xover[ch]; |
| |
| for (int i = 0; i < in->nb_samples; i++) { |
| double sample = src[i], lo, hi; |
| |
| for (band = 0; band < ctx->nb_outputs; band++) { |
| double *dst = (double *)frames[band]->extended_data[ch]; |
| |
| lo = sample; |
| hi = sample; |
| for (f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) { |
| BiquadContext *lp = &xover->lp[band][f]; |
| lo = biquad_process(lp, lo); |
| } |
| |
| for (f = 0; band + 1 < ctx->nb_outputs && f < s->filter_count; f++) { |
| BiquadContext *hp = &xover->hp[band][f]; |
| hi = biquad_process(hp, hi); |
| } |
| |
| dst[i] = lo; |
| |
| sample = hi; |
| } |
| } |
| } |
| |
| return 0; |
| } |
| |
| static int filter_frame(AVFilterLink *inlink, AVFrame *in) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| AudioCrossoverContext *s = ctx->priv; |
| AVFrame **frames = s->frames; |
| int i, ret = 0; |
| |
| for (i = 0; i < ctx->nb_outputs; i++) { |
| frames[i] = ff_get_audio_buffer(ctx->outputs[i], in->nb_samples); |
| |
| if (!frames[i]) { |
| ret = AVERROR(ENOMEM); |
| break; |
| } |
| |
| frames[i]->pts = in->pts; |
| } |
| |
| if (ret < 0) |
| goto fail; |
| |
| s->input_frame = in; |
| ctx->internal->execute(ctx, filter_channels, NULL, NULL, FFMIN(inlink->channels, |
| ff_filter_get_nb_threads(ctx))); |
| |
| for (i = 0; i < ctx->nb_outputs; i++) { |
| ret = ff_filter_frame(ctx->outputs[i], frames[i]); |
| frames[i] = NULL; |
| if (ret < 0) |
| break; |
| } |
| |
| fail: |
| for (i = 0; i < ctx->nb_outputs; i++) |
| av_frame_free(&frames[i]); |
| av_frame_free(&in); |
| s->input_frame = NULL; |
| |
| return ret; |
| } |
| |
| static av_cold void uninit(AVFilterContext *ctx) |
| { |
| AudioCrossoverContext *s = ctx->priv; |
| int i; |
| |
| av_freep(&s->splits); |
| av_freep(&s->xover); |
| |
| for (i = 0; i < ctx->nb_outputs; i++) |
| av_freep(&ctx->output_pads[i].name); |
| } |
| |
| static const AVFilterPad inputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .filter_frame = filter_frame, |
| .config_props = config_input, |
| }, |
| { NULL } |
| }; |
| |
| AVFilter ff_af_acrossover = { |
| .name = "acrossover", |
| .description = NULL_IF_CONFIG_SMALL("Split audio into per-bands streams."), |
| .priv_size = sizeof(AudioCrossoverContext), |
| .priv_class = &acrossover_class, |
| .init = init, |
| .uninit = uninit, |
| .query_formats = query_formats, |
| .inputs = inputs, |
| .outputs = NULL, |
| .flags = AVFILTER_FLAG_DYNAMIC_OUTPUTS | |
| AVFILTER_FLAG_SLICE_THREADS, |
| }; |