| /* |
| * 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" |
| |
| #define MAX_ORDER 30 |
| |
| typedef struct Coeffs { |
| double g; |
| double a1; |
| double b0, b1; |
| } Coeffs; |
| |
| typedef struct ATiltContext { |
| const AVClass *class; |
| |
| double freq; |
| double level; |
| double slope; |
| double width; |
| int order; |
| |
| Coeffs coeffs[MAX_ORDER]; |
| |
| AVFrame *w; |
| |
| int (*filter_channels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs); |
| } ATiltContext; |
| |
| static double prewarp(double w, double T, double wp) |
| { |
| return wp * tan(w * T * 0.5) / tan(wp * T * 0.5); |
| } |
| |
| static double mz(int i, double w0, double r, double alpha) |
| { |
| return w0 * pow(r, -alpha + i); |
| } |
| |
| static double mp(int i, double w0, double r) |
| { |
| return w0 * pow(r, i); |
| } |
| |
| static double mzh(int i, double T, double w0, double r, double alpha) |
| { |
| return prewarp(mz(i, w0, r, alpha), T, w0); |
| } |
| |
| static double mph(int i, double T, double w0, double r) |
| { |
| return prewarp(mp(i, w0, r), T, w0); |
| } |
| |
| static void set_tf1s(Coeffs *coeffs, double b1, double b0, double a0, |
| double w1, double sr, double alpha) |
| { |
| double c = 1.0 / tan(w1 * 0.5 / sr); |
| double d = a0 + c; |
| |
| coeffs->b1 = (b0 - b1 * c) / d; |
| coeffs->b0 = (b0 + b1 * c) / d; |
| coeffs->a1 = (a0 - c) / d; |
| coeffs->g = a0 / b0; |
| } |
| |
| static void set_filter(AVFilterContext *ctx, |
| int order, double sr, double f0, |
| double bw, double alpha) |
| { |
| ATiltContext *s = ctx->priv; |
| const double w0 = 2. * M_PI * f0; |
| const double f1 = f0 + bw; |
| const double w1 = 1.; |
| const double r = pow(f1 / f0, 1.0 / (order - 1.0)); |
| const double T = 1. / sr; |
| |
| for (int i = 0; i < order; i++) { |
| Coeffs *coeffs = &s->coeffs[i]; |
| |
| set_tf1s(coeffs, 1.0, mzh(i, T, w0, r, alpha), mph(i, T, w0, r), |
| w1, sr, alpha); |
| } |
| } |
| |
| static int get_coeffs(AVFilterContext *ctx) |
| { |
| ATiltContext *s = ctx->priv; |
| AVFilterLink *inlink = ctx->inputs[0]; |
| |
| set_filter(ctx, s->order, inlink->sample_rate, s->freq, s->width, s->slope); |
| |
| return 0; |
| } |
| |
| typedef struct ThreadData { |
| AVFrame *in, *out; |
| } ThreadData; |
| |
| #define FILTER(name, type) \ |
| static int filter_channels_## name(AVFilterContext *ctx, void *arg, \ |
| int jobnr, int nb_jobs) \ |
| { \ |
| ATiltContext *s = ctx->priv; \ |
| ThreadData *td = arg; \ |
| AVFrame *out = td->out; \ |
| AVFrame *in = td->in; \ |
| const int start = (in->ch_layout.nb_channels * jobnr) / nb_jobs; \ |
| const int end = (in->ch_layout.nb_channels * (jobnr+1)) / nb_jobs; \ |
| const type level = s->level; \ |
| \ |
| for (int ch = start; ch < end; ch++) { \ |
| const type *src = (const type *)in->extended_data[ch]; \ |
| type *dst = (type *)out->extended_data[ch]; \ |
| \ |
| for (int b = 0; b < s->order; b++) { \ |
| Coeffs *coeffs = &s->coeffs[b]; \ |
| const type g = coeffs->g; \ |
| const type a1 = coeffs->a1; \ |
| const type b0 = coeffs->b0; \ |
| const type b1 = coeffs->b1; \ |
| type *w = ((type *)s->w->extended_data[ch]) + b * 2; \ |
| \ |
| for (int n = 0; n < in->nb_samples; n++) { \ |
| type sain = b ? dst[n] : src[n] * level; \ |
| type saout = sain * b0 + w[0] * b1 - w[1] * a1; \ |
| \ |
| w[0] = sain; \ |
| w[1] = saout; \ |
| \ |
| dst[n] = saout * g; \ |
| } \ |
| } \ |
| } \ |
| \ |
| return 0; \ |
| } |
| |
| FILTER(fltp, float) |
| FILTER(dblp, double) |
| |
| static int config_input(AVFilterLink *inlink) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| ATiltContext *s = ctx->priv; |
| |
| switch (inlink->format) { |
| case AV_SAMPLE_FMT_FLTP: s->filter_channels = filter_channels_fltp; break; |
| case AV_SAMPLE_FMT_DBLP: s->filter_channels = filter_channels_dblp; break; |
| } |
| |
| s->w = ff_get_audio_buffer(inlink, 2 * MAX_ORDER); |
| if (!s->w) |
| return AVERROR(ENOMEM); |
| |
| return get_coeffs(ctx); |
| } |
| |
| static int filter_frame(AVFilterLink *inlink, AVFrame *in) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| ATiltContext *s = ctx->priv; |
| AVFilterLink *outlink = ctx->outputs[0]; |
| ThreadData td; |
| 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); |
| } |
| |
| td.in = in; td.out = out; |
| ff_filter_execute(ctx, s->filter_channels, &td, NULL, FFMIN(inlink->ch_layout.nb_channels, |
| ff_filter_get_nb_threads(ctx))); |
| |
| if (out != 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) |
| { |
| int ret; |
| |
| ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags); |
| if (ret < 0) |
| return ret; |
| |
| return get_coeffs(ctx); |
| } |
| |
| static av_cold void uninit(AVFilterContext *ctx) |
| { |
| ATiltContext *s = ctx->priv; |
| |
| av_frame_free(&s->w); |
| } |
| |
| #define OFFSET(x) offsetof(ATiltContext, x) |
| #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM |
| |
| static const AVOption atilt_options[] = { |
| { "freq", "set central frequency",OFFSET(freq), AV_OPT_TYPE_DOUBLE, {.dbl=10000}, 20, 192000, FLAGS }, |
| { "slope", "set filter slope", OFFSET(slope), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -1, 1, FLAGS }, |
| { "width", "set filter width", OFFSET(width), AV_OPT_TYPE_DOUBLE, {.dbl=1000}, 100, 10000, FLAGS }, |
| { "order", "set filter order", OFFSET(order), AV_OPT_TYPE_INT, {.i64=5}, 2,MAX_ORDER, FLAGS }, |
| { "level", "set input level", OFFSET(level), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0., 4., FLAGS }, |
| { NULL } |
| }; |
| |
| AVFILTER_DEFINE_CLASS(atilt); |
| |
| static const AVFilterPad inputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .filter_frame = filter_frame, |
| .config_props = config_input, |
| }, |
| }; |
| |
| static const AVFilterPad outputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| }, |
| }; |
| |
| const AVFilter ff_af_atilt = { |
| .name = "atilt", |
| .description = NULL_IF_CONFIG_SMALL("Apply spectral tilt to audio."), |
| .priv_size = sizeof(ATiltContext), |
| .priv_class = &atilt_class, |
| .uninit = uninit, |
| FILTER_INPUTS(inputs), |
| FILTER_OUTPUTS(outputs), |
| FILTER_SAMPLEFMTS(AV_SAMPLE_FMT_FLTP, AV_SAMPLE_FMT_DBLP), |
| .process_command = process_command, |
| .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC | |
| AVFILTER_FLAG_SLICE_THREADS, |
| }; |