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author | Paul B Mahol <onemda@gmail.com> | 2017-05-14 18:30:12 +0200 |
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committer | Paul B Mahol <onemda@gmail.com> | 2017-05-17 20:18:39 +0200 |
commit | deaab31d61fd3679491a5e81cd26432886815ddf (patch) | |
tree | accbc68fcf0b77c68dfd16dfd7a44f0c3815610b /libavfilter/af_crossfeed.c | |
parent | 94d05ff15985d17aba070eaec82acd21c0da3d86 (diff) | |
download | ffmpeg-deaab31d61fd3679491a5e81cd26432886815ddf.tar.gz |
avfilter: add audio crossfeed filter
Signed-off-by: Paul B Mahol <onemda@gmail.com>
Diffstat (limited to 'libavfilter/af_crossfeed.c')
-rw-r--r-- | libavfilter/af_crossfeed.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/libavfilter/af_crossfeed.c b/libavfilter/af_crossfeed.c new file mode 100644 index 0000000000..d3def92fb3 --- /dev/null +++ b/libavfilter/af_crossfeed.c @@ -0,0 +1,169 @@ +/* + * 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/opt.h" +#include "avfilter.h" +#include "audio.h" +#include "formats.h" + +typedef struct CrossfeedContext { + const AVClass *class; + + double range; + double strength; + double level_in; + double level_out; + + double a0, a1, a2; + double b0, b1, b2; + + double i1, i2; + double o1, o2; +} CrossfeedContext; + +static int query_formats(AVFilterContext *ctx) +{ + AVFilterFormats *formats = NULL; + AVFilterChannelLayouts *layout = NULL; + int ret; + + if ((ret = ff_add_format (&formats, AV_SAMPLE_FMT_DBL )) < 0 || + (ret = ff_set_common_formats (ctx , formats )) < 0 || + (ret = ff_add_channel_layout (&layout , AV_CH_LAYOUT_STEREO)) < 0 || + (ret = ff_set_common_channel_layouts (ctx , layout )) < 0 || + (ret = ff_set_common_samplerates (ctx , ff_all_samplerates())) < 0) + return ret; + + return 0; +} + +static int config_input(AVFilterLink *inlink) +{ + AVFilterContext *ctx = inlink->dst; + CrossfeedContext *s = ctx->priv; + double A = exp(s->strength * -30 / 40 * log(10.)); + double w0 = 2 * M_PI * (1. - s->range) * 2100 / inlink->sample_rate; + double alpha; + + alpha = sin(w0) / 2 * sqrt(2 * (1 / 0.5 - 1) + 2); + + s->a0 = (A + 1) + (A - 1) * cos(w0) + 2 * sqrt(A) * alpha; + s->a1 = -2 * ((A - 1) + (A + 1) * cos(w0)); + s->a2 = (A + 1) + (A - 1) * cos(w0) - 2 * sqrt(A) * alpha; + s->b0 = A * ((A + 1) - (A - 1) * cos(w0) + 2 * sqrt(A) * alpha); + s->b1 = 2 * A * ((A - 1) - (A + 1) * cos(w0)); + s->b2 = A * ((A + 1) - (A - 1) * cos(w0) - 2 * sqrt(A) * alpha); + + s->a1 /= s->a0; + s->a2 /= s->a0; + s->b0 /= s->a0; + s->b1 /= s->a0; + s->b2 /= s->a0; + + return 0; +} + +static int filter_frame(AVFilterLink *inlink, AVFrame *in) +{ + AVFilterContext *ctx = inlink->dst; + AVFilterLink *outlink = ctx->outputs[0]; + CrossfeedContext *s = ctx->priv; + const double *src = (const double *)in->data[0]; + const double level_in = s->level_in; + const double level_out = s->level_out; + const double b0 = s->b0; + const double b1 = s->b1; + const double b2 = s->b2; + const double a1 = s->a1; + const double a2 = s->a2; + AVFrame *out; + double *dst; + int n; + + 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 < out->nb_samples; n++, src += 2, dst += 2) { + double mid = (src[0] + src[1]) * level_in * .5; + double side = (src[0] - src[1]) * level_in * .5; + double oside = side * b0 + s->i1 * b1 + s->i2 * b2 - s->o1 * a1 - s->o2 * a2; + + s->i2 = s->i1; + s->i1 = side; + s->o2 = s->o1; + s->o1 = oside; + + dst[0] = (mid + oside) * level_out; + dst[1] = (mid - oside) * level_out; + } + + if (out != in) + av_frame_free(&in); + return ff_filter_frame(outlink, out); +} + +#define OFFSET(x) offsetof(CrossfeedContext, x) +#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM + +static const AVOption crossfeed_options[] = { + { "strength", "set crossfeed strength", OFFSET(strength), AV_OPT_TYPE_DOUBLE, {.dbl=.2}, 0, 1, FLAGS }, + { "range", "set soundstage wideness", OFFSET(range), AV_OPT_TYPE_DOUBLE, {.dbl=.5}, 0, 1, FLAGS }, + { "level_in", "set level in", OFFSET(level_in), AV_OPT_TYPE_DOUBLE, {.dbl=.9}, 0, 1, FLAGS }, + { "level_out", "set level out", OFFSET(level_out), AV_OPT_TYPE_DOUBLE, {.dbl=1.}, 0, 1, FLAGS }, + { NULL } +}; + +AVFILTER_DEFINE_CLASS(crossfeed); + +static const AVFilterPad inputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .filter_frame = filter_frame, + .config_props = config_input, + }, + { NULL } +}; + +static const AVFilterPad outputs[] = { + { + .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + }, + { NULL } +}; + +AVFilter ff_af_crossfeed = { + .name = "crossfeed", + .description = NULL_IF_CONFIG_SMALL("Apply headphone crossfeed filter."), + .query_formats = query_formats, + .priv_size = sizeof(CrossfeedContext), + .priv_class = &crossfeed_class, + .inputs = inputs, + .outputs = outputs, +}; |