diff options
Diffstat (limited to 'libavfilter/af_tremolo.c')
| -rw-r--r-- | libavfilter/af_tremolo.c | 170 |
1 files changed, 170 insertions, 0 deletions
diff --git a/libavfilter/af_tremolo.c b/libavfilter/af_tremolo.c new file mode 100644 index 0000000000..572e9e3b56 --- /dev/null +++ b/libavfilter/af_tremolo.c @@ -0,0 +1,170 @@ +/* + * 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 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(inlink, 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 >= inlink->sample_rate / s->freq) + 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 = av_malloc_array(inlink->sample_rate / s->freq, sizeof(*s->table)); + if (!s->table) + return AVERROR(ENOMEM); + + for (i = 0; i < inlink->sample_rate / s->freq; 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, +}; |