| /* |
| * Copyright (c) 2015 Kyle Swanson <k@ylo.ph>. |
| * |
| * 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/opt.h" |
| #include "avfilter.h" |
| #include "internal.h" |
| #include "audio.h" |
| |
| typedef struct TremoloContext { |
| const AVClass *class; |
| double freq; |
| double depth; |
| double *table; |
| int table_size; |
| int index; |
| } TremoloContext; |
| |
| #define OFFSET(x) offsetof(TremoloContext, x) |
| #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM |
| |
| static const AVOption tremolo_options[] = { |
| { "f", "set frequency in hertz", OFFSET(freq), AV_OPT_TYPE_DOUBLE, {.dbl = 5.0}, 0.1, 20000.0, FLAGS }, |
| { "d", "set depth as percentage", OFFSET(depth), AV_OPT_TYPE_DOUBLE, {.dbl = 0.5}, 0.0, 1.0, FLAGS }, |
| { NULL } |
| }; |
| |
| AVFILTER_DEFINE_CLASS(tremolo); |
| |
| static int filter_frame(AVFilterLink *inlink, AVFrame *in) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| AVFilterLink *outlink = ctx->outputs[0]; |
| TremoloContext *s = ctx->priv; |
| const double *src = (const double *)in->data[0]; |
| const int channels = inlink->channels; |
| const int nb_samples = in->nb_samples; |
| AVFrame *out; |
| double *dst; |
| int n, c; |
| |
| 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); |
| } |
| dst = (double *)out->data[0]; |
| |
| for (n = 0; n < nb_samples; n++) { |
| for (c = 0; c < channels; c++) |
| dst[c] = src[c] * s->table[s->index]; |
| dst += channels; |
| src += channels; |
| s->index++; |
| if (s->index >= s->table_size) |
| s->index = 0; |
| } |
| |
| if (in != out) |
| av_frame_free(&in); |
| |
| return ff_filter_frame(outlink, out); |
| } |
| |
| static int query_formats(AVFilterContext *ctx) |
| { |
| AVFilterFormats *formats; |
| AVFilterChannelLayouts *layouts; |
| static const enum AVSampleFormat sample_fmts[] = { |
| AV_SAMPLE_FMT_DBL, |
| 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 av_cold void uninit(AVFilterContext *ctx) |
| { |
| TremoloContext *s = ctx->priv; |
| av_freep(&s->table); |
| } |
| |
| static int config_input(AVFilterLink *inlink) |
| { |
| AVFilterContext *ctx = inlink->dst; |
| TremoloContext *s = ctx->priv; |
| const double offset = 1. - s->depth / 2.; |
| int i; |
| |
| s->table_size = inlink->sample_rate / s->freq; |
| s->table = av_malloc_array(s->table_size, sizeof(*s->table)); |
| if (!s->table) |
| return AVERROR(ENOMEM); |
| |
| for (i = 0; i < s->table_size; i++) { |
| double env = s->freq * i / inlink->sample_rate; |
| env = sin(2 * M_PI * fmod(env + 0.25, 1.0)); |
| s->table[i] = env * (1 - fabs(offset)) + offset; |
| } |
| |
| s->index = 0; |
| |
| return 0; |
| } |
| |
| static const AVFilterPad avfilter_af_tremolo_inputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| .config_props = config_input, |
| .filter_frame = filter_frame, |
| }, |
| { NULL } |
| }; |
| |
| static const AVFilterPad avfilter_af_tremolo_outputs[] = { |
| { |
| .name = "default", |
| .type = AVMEDIA_TYPE_AUDIO, |
| }, |
| { NULL } |
| }; |
| |
| AVFilter ff_af_tremolo = { |
| .name = "tremolo", |
| .description = NULL_IF_CONFIG_SMALL("Apply tremolo effect."), |
| .priv_size = sizeof(TremoloContext), |
| .priv_class = &tremolo_class, |
| .uninit = uninit, |
| .query_formats = query_formats, |
| .inputs = avfilter_af_tremolo_inputs, |
| .outputs = avfilter_af_tremolo_outputs, |
| }; |