libavfilter/asrc_hilbert.c

   1 /*
   2  * Copyright (c) 2018 Paul B Mahol
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public License
   8  * as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public License
  17  * along with FFmpeg; if not, write to the Free Software Foundation, Inc.,
  18  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "libavutil/channel_layout.h"
  22 #include "libavutil/mem.h"
  23 #include "libavutil/opt.h"
  24 #include "audio.h"
  25 #include "avfilter.h"
  26 #include "formats.h"
  27 #include "filters.h"
  28 #include "window_func.h"
  29
  30 typedef struct HilbertContext {
  31     const AVClass *class;
  32
  33     int sample_rate;
  34     int nb_taps;
  35     int nb_samples;
  36     int win_func;
  37
  38     float *taps;
  39     int64_t pts;
  40 } HilbertContext;
  41
  42 #define OFFSET(x) offsetof(HilbertContext, x)
  43 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
  44
  45 static const AVOption hilbert_options[] = {
  46     { "sample_rate", "set sample rate",    OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100},  1, INT_MAX,    FLAGS },
  47     { "r",           "set sample rate",    OFFSET(sample_rate), AV_OPT_TYPE_INT, {.i64=44100},  1, INT_MAX,    FLAGS },
  48     { "taps",        "set number of taps", OFFSET(nb_taps),     AV_OPT_TYPE_INT, {.i64=22051}, 11, UINT16_MAX, FLAGS },
  49     { "t",           "set number of taps", OFFSET(nb_taps),     AV_OPT_TYPE_INT, {.i64=22051}, 11, UINT16_MAX, FLAGS },
  50     { "nb_samples",  "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
  51     { "n",           "set the number of samples per requested frame", OFFSET(nb_samples), AV_OPT_TYPE_INT, {.i64 = 1024}, 1, INT_MAX, FLAGS },
  52     WIN_FUNC_OPTION("win_func", OFFSET(win_func), FLAGS, WFUNC_BLACKMAN),
  53     WIN_FUNC_OPTION("w",        OFFSET(win_func), FLAGS, WFUNC_BLACKMAN),
  54     {NULL}
  55 };
  56
  57 AVFILTER_DEFINE_CLASS(hilbert);
  58
  59 static av_cold int init(AVFilterContext *ctx)
  60 {
  61     HilbertContext *s = ctx->priv;
  62
  63     if (!(s->nb_taps & 1)) {
  64         av_log(s, AV_LOG_ERROR, "Number of taps %d must be odd length.\n", s->nb_taps);
  65         return AVERROR(EINVAL);
  66     }
  67
  68     return 0;
  69 }
  70
  71 static av_cold void uninit(AVFilterContext *ctx)
  72 {
  73     HilbertContext *s = ctx->priv;
  74
  75     av_freep(&s->taps);
  76 }
  77
  78 static av_cold int query_formats(const AVFilterContext *ctx,
  79                                  AVFilterFormatsConfig **cfg_in,
  80                                  AVFilterFormatsConfig **cfg_out)
  81 {
  82     HilbertContext *s = ctx->priv;
  83     static const AVChannelLayout chlayouts[] = { AV_CHANNEL_LAYOUT_MONO, { 0 } };
  84     int sample_rates[] = { s->sample_rate, -1 };
  85     static const enum AVSampleFormat sample_fmts[] = {
  86         AV_SAMPLE_FMT_FLT,
  87         AV_SAMPLE_FMT_NONE
  88     };
  89     int ret = ff_set_common_formats_from_list2(ctx, cfg_in, cfg_out, sample_fmts);
  90     if (ret < 0)
  91         return ret;
  92
  93     ret = ff_set_common_channel_layouts_from_list2(ctx, cfg_in, cfg_out, chlayouts);
  94     if (ret < 0)
  95         return ret;
  96
  97     return ff_set_common_samplerates_from_list2(ctx, cfg_in, cfg_out, sample_rates);
  98 }
  99
 100 static av_cold int config_props(AVFilterLink *outlink)
 101 {
 102     AVFilterContext *ctx = outlink->src;
 103     HilbertContext *s = ctx->priv;
 104     float overlap;
 105     int i;
 106
 107     s->taps = av_malloc_array(s->nb_taps, sizeof(*s->taps));
 108     if (!s->taps)
 109         return AVERROR(ENOMEM);
 110
 111     generate_window_func(s->taps, s->nb_taps, s->win_func, &overlap);
 112
 113     for (i = 0; i < s->nb_taps; i++) {
 114         int k = -(s->nb_taps / 2) + i;
 115
 116         if (k & 1) {
 117             float pk = M_PI * k;
 118
 119             s->taps[i] *= (1.f - cosf(pk)) / pk;
 120         } else {
 121             s->taps[i] = 0.f;
 122         }
 123     }
 124
 125     s->pts = 0;
 126
 127     return 0;
 128 }
 129
 130 static int activate(AVFilterContext *ctx)
 131 {
 132     AVFilterLink *outlink = ctx->outputs[0];
 133     HilbertContext *s = ctx->priv;
 134     AVFrame *frame;
 135     int nb_samples;
 136
 137     if (!ff_outlink_frame_wanted(outlink))
 138         return FFERROR_NOT_READY;
 139
 140     nb_samples = FFMIN(s->nb_samples, s->nb_taps - s->pts);
 141     if (nb_samples <= 0) {
 142         ff_outlink_set_status(outlink, AVERROR_EOF, s->pts);
 143         return 0;
 144     }
 145
 146     if (!(frame = ff_get_audio_buffer(outlink, nb_samples)))
 147         return AVERROR(ENOMEM);
 148
 149     memcpy(frame->data[0], s->taps + s->pts, nb_samples * sizeof(float));
 150
 151     frame->pts = s->pts;
 152     s->pts    += nb_samples;
 153     return ff_filter_frame(outlink, frame);
 154 }
 155
 156 static const AVFilterPad hilbert_outputs[] = {
 157     {
 158         .name          = "default",
 159         .type          = AVMEDIA_TYPE_AUDIO,
 160         .config_props  = config_props,
 161     },
 162 };
 163
 164 const FFFilter ff_asrc_hilbert = {
 165     .p.name        = "hilbert",
 166     .p.description = NULL_IF_CONFIG_SMALL("Generate a Hilbert transform FIR coefficients."),
 167     .p.priv_class  = &hilbert_class,
 168     .init          = init,
 169     .uninit        = uninit,
 170     .activate      = activate,
 171     .priv_size     = sizeof(HilbertContext),
 172     FILTER_OUTPUTS(hilbert_outputs),
 173     FILTER_QUERY_FUNC2(query_formats),
 174 };