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Diffstat (limited to 'libavfilter/af_earwax.c')
| -rw-r--r-- | libavfilter/af_earwax.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/libavfilter/af_earwax.c b/libavfilter/af_earwax.c new file mode 100644 index 0000000..7265c43 --- /dev/null +++ b/libavfilter/af_earwax.c @@ -0,0 +1,169 @@ +/* + * Copyright (c) 2011 Mina Nagy Zaki + * Copyright (c) 2000 Edward Beingessner And Sundry Contributors. + * This source code is freely redistributable and may be used for any purpose. + * This copyright notice must be maintained. Edward Beingessner And Sundry + * Contributors are not responsible for the consequences of using this + * software. + * + * 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 + */ + +/** + * @file + * Stereo Widening Effect. Adds audio cues to move stereo image in + * front of the listener. Adapted from the libsox earwax effect. + */ + +#include "libavutil/audioconvert.h" +#include "avfilter.h" +#include "audio.h" +#include "formats.h" + +#define NUMTAPS 64 + +static const int8_t filt[NUMTAPS] = { +/* 30° 330° */ + 4, -6, /* 32 tap stereo FIR filter. */ + 4, -11, /* One side filters as if the */ + -1, -5, /* signal was from 30 degrees */ + 3, 3, /* from the ear, the other as */ + -2, 5, /* if 330 degrees. */ + -5, 0, + 9, 1, + 6, 3, /* Input */ + -4, -1, /* Left Right */ + -5, -3, /* __________ __________ */ + -2, -5, /* | | | | */ + -7, 1, /* .---| Hh,0(f) | | Hh,0(f) |---. */ + 6, -7, /* / |__________| |__________| \ */ + 30, -29, /* / \ / \ */ + 12, -3, /* / X \ */ + -11, 4, /* / / \ \ */ + -3, 7, /* ____V_____ __________V V__________ _____V____ */ + -20, 23, /* | | | | | | | | */ + 2, 0, /* | Hh,30(f) | | Hh,330(f)| | Hh,330(f)| | Hh,30(f) | */ + 1, -6, /* |__________| |__________| |__________| |__________| */ + -14, -5, /* \ ___ / \ ___ / */ + 15, -18, /* \ / \ / _____ \ / \ / */ + 6, 7, /* `->| + |<--' / \ `-->| + |<-' */ + 15, -10, /* \___/ _/ \_ \___/ */ + -14, 22, /* \ / \ / \ / */ + -7, -2, /* `--->| | | |<---' */ + -4, 9, /* \_/ \_/ */ + 6, -12, /* */ + 6, -6, /* Headphones */ + 0, -11, + 0, -5, + 4, 0}; + +typedef struct { + int16_t taps[NUMTAPS * 2]; +} EarwaxContext; + +static int query_formats(AVFilterContext *ctx) +{ + int sample_rates[] = { 44100, -1 }; + + AVFilterFormats *formats = NULL; + AVFilterChannelLayouts *layout = NULL; + + ff_add_format(&formats, AV_SAMPLE_FMT_S16); + ff_set_common_formats(ctx, formats); + ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO); + ff_set_common_channel_layouts(ctx, layout); + ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates)); + + return 0; +} + +static int config_input(AVFilterLink *inlink) +{ + if (inlink->sample_rate != 44100) { + av_log(inlink->dst, AV_LOG_ERROR, + "The earwax filter only works for 44.1kHz audio. Insert " + "a resample filter before this\n"); + return AVERROR(EINVAL); + } + return 0; +} + +//FIXME: replace with DSPContext.scalarproduct_int16 +static inline int16_t *scalarproduct(const int16_t *in, const int16_t *endin, int16_t *out) +{ + int32_t sample; + int16_t j; + + while (in < endin) { + sample = 32; + for (j = 0; j < NUMTAPS; j++) + sample += in[j] * filt[j]; + *out = sample >> 6; + out++; + in++; + } + + return out; +} + +static int filter_samples(AVFilterLink *inlink, AVFilterBufferRef *insamples) +{ + AVFilterLink *outlink = inlink->dst->outputs[0]; + int16_t *taps, *endin, *in, *out; + AVFilterBufferRef *outsamples = + ff_get_audio_buffer(inlink, AV_PERM_WRITE, + insamples->audio->nb_samples); + int ret; + + avfilter_copy_buffer_ref_props(outsamples, insamples); + + taps = ((EarwaxContext *)inlink->dst->priv)->taps; + out = (int16_t *)outsamples->data[0]; + in = (int16_t *)insamples ->data[0]; + + // copy part of new input and process with saved input + memcpy(taps+NUMTAPS, in, NUMTAPS * sizeof(*taps)); + out = scalarproduct(taps, taps + NUMTAPS, out); + + // process current input + endin = in + insamples->audio->nb_samples * 2 - NUMTAPS; + out = scalarproduct(in, endin, out); + + // save part of input for next round + memcpy(taps, endin, NUMTAPS * sizeof(*taps)); + + ret = ff_filter_samples(outlink, outsamples); + avfilter_unref_buffer(insamples); + return ret; +} + +AVFilter avfilter_af_earwax = { + .name = "earwax", + .description = NULL_IF_CONFIG_SMALL("Widen the stereo image."), + .query_formats = query_formats, + .priv_size = sizeof(EarwaxContext), + .inputs = (const AVFilterPad[]) {{ .name = "default", + .type = AVMEDIA_TYPE_AUDIO, + .filter_samples = filter_samples, + .config_props = config_input, + .min_perms = AV_PERM_READ, }, + { .name = NULL}}, + + .outputs = (const AVFilterPad[]) {{ .name = "default", + .type = AVMEDIA_TYPE_AUDIO, }, + { .name = NULL}}, +}; |
