git.sesse.net Git - ffmpeg/blob - libavfilter/af_asupercut.c

   1 /*
   2  * This file is part of FFmpeg.
   3  *
   4  * FFmpeg is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * FFmpeg is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with FFmpeg; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  17  */
  18
  19 #include "libavutil/channel_layout.h"
  20 #include "libavutil/ffmath.h"
  21 #include "libavutil/opt.h"
  22 #include "avfilter.h"
  23 #include "audio.h"
  24 #include "formats.h"
  25
  26 typedef struct BiquadCoeffs {
  27     double a1, a2;
  28     double b0, b1, b2;
  29 } BiquadCoeffs;
  30
  31 typedef struct ASuperCutContext {
  32     const AVClass *class;
  33
  34     double cutoff;
  35     int order;
  36
  37     int filter_count;
  38     int bypass;
  39
  40     BiquadCoeffs coeffs[10];
  41
  42     AVFrame *w;
  43
  44     int (*filter_channels)(AVFilterContext *ctx, void *arg, int jobnr, int nb_jobs);
  45 } ASuperCutContext;
  46
  47 static int query_formats(AVFilterContext *ctx)
  48 {
  49     AVFilterFormats *formats = NULL;
  50     AVFilterChannelLayouts *layouts = NULL;
  51     static const enum AVSampleFormat sample_fmts[] = {
  52         AV_SAMPLE_FMT_FLTP,
  53         AV_SAMPLE_FMT_DBLP,
  54         AV_SAMPLE_FMT_NONE
  55     };
  56     int ret;
  57
  58     formats = ff_make_format_list(sample_fmts);
  59     if (!formats)
  60         return AVERROR(ENOMEM);
  61     ret = ff_set_common_formats(ctx, formats);
  62     if (ret < 0)
  63         return ret;
  64
  65     layouts = ff_all_channel_counts();
  66     if (!layouts)
  67         return AVERROR(ENOMEM);
  68
  69     ret = ff_set_common_channel_layouts(ctx, layouts);
  70     if (ret < 0)
  71         return ret;
  72
  73     formats = ff_all_samplerates();
  74     return ff_set_common_samplerates(ctx, formats);
  75 }
  76
  77 static void calc_q_factors(int n, double *q)
  78 {
  79     for (int i = 0; i < n / 2; i++)
  80         q[i] = 1. / (-2. * cos(M_PI * (2. * (i + 1) + n - 1.) / (2. * n)));
  81 }
  82
  83 static int get_coeffs(AVFilterContext *ctx)
  84 {
  85     ASuperCutContext *s = ctx->priv;
  86     AVFilterLink *inlink = ctx->inputs[0];
  87     double w0 = s->cutoff / inlink->sample_rate;
  88     double K = tan(M_PI * w0);
  89     double q[10];
  90
  91     s->bypass = w0 >= 0.5;
  92     if (s->bypass)
  93         return 0;
  94
  95     s->filter_count = s->order / 2 + (s->order & 1);
  96     calc_q_factors(s->order, q);
  97
  98     if (s->order & 1) {
  99         BiquadCoeffs *coeffs = &s->coeffs[0];
 100         double omega = 2. * tan(M_PI * w0);
 101
 102         coeffs->b0 = omega / (2. + omega);
 103         coeffs->b1 = coeffs->b0;
 104         coeffs->b2 = 0.;
 105         coeffs->a1 = -(omega - 2.) / (2. + omega);
 106         coeffs->a2 = 0.;
 107     }
 108
 109     for (int b = (s->order & 1); b < s->filter_count; b++) {
 110         BiquadCoeffs *coeffs = &s->coeffs[b];
 111         const int idx = b - (s->order & 1);
 112         double norm = 1.0 / (1.0 + K / q[idx] + K * K);
 113
 114         coeffs->b0 = K * K * norm;
 115         coeffs->b1 = 2.0 * coeffs->b0;
 116         coeffs->b2 = coeffs->b0;
 117         coeffs->a1 = -2.0 * (K * K - 1.0) * norm;
 118         coeffs->a2 = -(1.0 - K / q[idx] + K * K) * norm;
 119     }
 120
 121     return 0;
 122 }
 123
 124 typedef struct ThreadData {
 125     AVFrame *in, *out;
 126 } ThreadData;
 127
 128 #define FILTER(name, type)                                          \
 129 static int filter_channels_## name(AVFilterContext *ctx, void *arg, \
 130                                    int jobnr, int nb_jobs)          \
 131 {                                                                   \
 132     ASuperCutContext *s = ctx->priv;                                \
 133     ThreadData *td = arg;                                           \
 134     AVFrame *out = td->out;                                         \
 135     AVFrame *in = td->in;                                           \
 136     const int start = (in->channels * jobnr) / nb_jobs;             \
 137     const int end = (in->channels * (jobnr+1)) / nb_jobs;           \
 138                                                                     \
 139     for (int ch = start; ch < end; ch++) {                          \
 140         const type *src = (const type *)in->extended_data[ch];      \
 141         type *dst = (type *)out->extended_data[ch];                 \
 142                                                                     \
 143         for (int b = 0; b < s->filter_count; b++) {                 \
 144             BiquadCoeffs *coeffs = &s->coeffs[b];                   \
 145             const type a1 = coeffs->a1;                             \
 146             const type a2 = coeffs->a2;                             \
 147             const type b0 = coeffs->b0;                             \
 148             const type b1 = coeffs->b1;                             \
 149             const type b2 = coeffs->b2;                             \
 150             type *w = ((type *)s->w->extended_data[ch]) + b * 2;    \
 151                                                                     \
 152             for (int n = 0; n < in->nb_samples; n++) {              \
 153                 type sin = b ? dst[n] : src[n];                     \
 154                 type sout = sin * b0 + w[0];                        \
 155                                                                     \
 156                 w[0] = b1 * sin + w[1] + a1 * sout;                 \
 157                 w[1] = b2 * sin + a2 * sout;                        \
 158                                                                     \
 159                 dst[n] = sout;                                      \
 160             }                                                       \
 161         }                                                           \
 162     }                                                               \
 163                                                                     \
 164     return 0;                                                       \
 165 }
 166
 167 FILTER(fltp, float)
 168 FILTER(dblp, double)
 169
 170 static int config_input(AVFilterLink *inlink)
 171 {
 172     AVFilterContext *ctx = inlink->dst;
 173     ASuperCutContext *s = ctx->priv;
 174
 175     switch (inlink->format) {
 176     case AV_SAMPLE_FMT_FLTP: s->filter_channels = filter_channels_fltp; break;
 177     case AV_SAMPLE_FMT_DBLP: s->filter_channels = filter_channels_dblp; break;
 178     }
 179
 180     s->w = ff_get_audio_buffer(inlink, 2 * 10);
 181     if (!s->w)
 182         return AVERROR(ENOMEM);
 183
 184     return get_coeffs(ctx);
 185 }
 186
 187 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
 188 {
 189     AVFilterContext *ctx = inlink->dst;
 190     ASuperCutContext *s = ctx->priv;
 191     AVFilterLink *outlink = ctx->outputs[0];
 192     ThreadData td;
 193     AVFrame *out;
 194
 195     if (s->bypass)
 196         return ff_filter_frame(outlink, in);
 197
 198     if (av_frame_is_writable(in)) {
 199         out = in;
 200     } else {
 201         out = ff_get_audio_buffer(outlink, in->nb_samples);
 202         if (!out) {
 203             av_frame_free(&in);
 204             return AVERROR(ENOMEM);
 205         }
 206         av_frame_copy_props(out, in);
 207     }
 208
 209     td.in = in; td.out = out;
 210     ctx->internal->execute(ctx, s->filter_channels, &td, NULL, FFMIN(inlink->channels,
 211                                                                ff_filter_get_nb_threads(ctx)));
 212
 213     if (out != in)
 214         av_frame_free(&in);
 215     return ff_filter_frame(outlink, out);
 216 }
 217
 218 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
 219                            char *res, int res_len, int flags)
 220 {
 221     int ret;
 222
 223     ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
 224     if (ret < 0)
 225         return ret;
 226
 227     return get_coeffs(ctx);
 228 }
 229
 230 static av_cold void uninit(AVFilterContext *ctx)
 231 {
 232     ASuperCutContext *s = ctx->priv;
 233
 234     av_frame_free(&s->w);
 235 }
 236
 237 #define OFFSET(x) offsetof(ASuperCutContext, x)
 238 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
 239
 240 static const AVOption asupercut_options[] = {
 241     { "cutoff", "set cutoff frequency", OFFSET(cutoff), AV_OPT_TYPE_DOUBLE, {.dbl=20000}, 20000, 192000, FLAGS },
 242     { "order",  "set filter order",     OFFSET(order),  AV_OPT_TYPE_INT,    {.i64=10},        3,     20, FLAGS },
 243     { NULL }
 244 };
 245
 246 AVFILTER_DEFINE_CLASS(asupercut);
 247
 248 static const AVFilterPad inputs[] = {
 249     {
 250         .name         = "default",
 251         .type         = AVMEDIA_TYPE_AUDIO,
 252         .filter_frame = filter_frame,
 253         .config_props = config_input,
 254     },
 255     { NULL }
 256 };
 257
 258 static const AVFilterPad outputs[] = {
 259     {
 260         .name = "default",
 261         .type = AVMEDIA_TYPE_AUDIO,
 262     },
 263     { NULL }
 264 };
 265
 266 AVFilter ff_af_asupercut = {
 267     .name            = "asupercut",
 268     .description     = NULL_IF_CONFIG_SMALL("Cut super frequencies."),
 269     .query_formats   = query_formats,
 270     .priv_size       = sizeof(ASuperCutContext),
 271     .priv_class      = &asupercut_class,
 272     .uninit          = uninit,
 273     .inputs          = inputs,
 274     .outputs         = outputs,
 275     .process_command = process_command,
 276     .flags           = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC |
 277                        AVFILTER_FLAG_SLICE_THREADS,
 278 };