| 1 | /* |
| 2 | * Copyright (c) 2011 Mina Nagy Zaki |
| 3 | * Copyright (c) 2000 Edward Beingessner And Sundry Contributors. |
| 4 | * This source code is freely redistributable and may be used for any purpose. |
| 5 | * This copyright notice must be maintained. Edward Beingessner And Sundry |
| 6 | * Contributors are not responsible for the consequences of using this |
| 7 | * software. |
| 8 | * |
| 9 | * This file is part of FFmpeg. |
| 10 | * |
| 11 | * FFmpeg is free software; you can redistribute it and/or |
| 12 | * modify it under the terms of the GNU Lesser General Public |
| 13 | * License as published by the Free Software Foundation; either |
| 14 | * version 2.1 of the License, or (at your option) any later version. |
| 15 | * |
| 16 | * FFmpeg is distributed in the hope that it will be useful, |
| 17 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 19 | * Lesser General Public License for more details. |
| 20 | * |
| 21 | * You should have received a copy of the GNU Lesser General Public |
| 22 | * License along with FFmpeg; if not, write to the Free Software |
| 23 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 24 | */ |
| 25 | |
| 26 | /** |
| 27 | * @file |
| 28 | * Stereo Widening Effect. Adds audio cues to move stereo image in |
| 29 | * front of the listener. Adapted from the libsox earwax effect. |
| 30 | */ |
| 31 | |
| 32 | #include "libavutil/channel_layout.h" |
| 33 | #include "avfilter.h" |
| 34 | #include "audio.h" |
| 35 | #include "formats.h" |
| 36 | |
| 37 | #define NUMTAPS 64 |
| 38 | |
| 39 | static const int8_t filt[NUMTAPS] = { |
| 40 | /* 30° 330° */ |
| 41 | 4, -6, /* 32 tap stereo FIR filter. */ |
| 42 | 4, -11, /* One side filters as if the */ |
| 43 | -1, -5, /* signal was from 30 degrees */ |
| 44 | 3, 3, /* from the ear, the other as */ |
| 45 | -2, 5, /* if 330 degrees. */ |
| 46 | -5, 0, |
| 47 | 9, 1, |
| 48 | 6, 3, /* Input */ |
| 49 | -4, -1, /* Left Right */ |
| 50 | -5, -3, /* __________ __________ */ |
| 51 | -2, -5, /* | | | | */ |
| 52 | -7, 1, /* .---| Hh,0(f) | | Hh,0(f) |---. */ |
| 53 | 6, -7, /* / |__________| |__________| \ */ |
| 54 | 30, -29, /* / \ / \ */ |
| 55 | 12, -3, /* / X \ */ |
| 56 | -11, 4, /* / / \ \ */ |
| 57 | -3, 7, /* ____V_____ __________V V__________ _____V____ */ |
| 58 | -20, 23, /* | | | | | | | | */ |
| 59 | 2, 0, /* | Hh,30(f) | | Hh,330(f)| | Hh,330(f)| | Hh,30(f) | */ |
| 60 | 1, -6, /* |__________| |__________| |__________| |__________| */ |
| 61 | -14, -5, /* \ ___ / \ ___ / */ |
| 62 | 15, -18, /* \ / \ / _____ \ / \ / */ |
| 63 | 6, 7, /* `->| + |<--' / \ `-->| + |<-' */ |
| 64 | 15, -10, /* \___/ _/ \_ \___/ */ |
| 65 | -14, 22, /* \ / \ / \ / */ |
| 66 | -7, -2, /* `--->| | | |<---' */ |
| 67 | -4, 9, /* \_/ \_/ */ |
| 68 | 6, -12, /* */ |
| 69 | 6, -6, /* Headphones */ |
| 70 | 0, -11, |
| 71 | 0, -5, |
| 72 | 4, 0}; |
| 73 | |
| 74 | typedef struct { |
| 75 | int16_t taps[NUMTAPS * 2]; |
| 76 | } EarwaxContext; |
| 77 | |
| 78 | static int query_formats(AVFilterContext *ctx) |
| 79 | { |
| 80 | static const int sample_rates[] = { 44100, -1 }; |
| 81 | |
| 82 | AVFilterFormats *formats = NULL; |
| 83 | AVFilterChannelLayouts *layout = NULL; |
| 84 | |
| 85 | ff_add_format(&formats, AV_SAMPLE_FMT_S16); |
| 86 | ff_set_common_formats(ctx, formats); |
| 87 | ff_add_channel_layout(&layout, AV_CH_LAYOUT_STEREO); |
| 88 | ff_set_common_channel_layouts(ctx, layout); |
| 89 | ff_set_common_samplerates(ctx, ff_make_format_list(sample_rates)); |
| 90 | |
| 91 | return 0; |
| 92 | } |
| 93 | |
| 94 | //FIXME: replace with DSPContext.scalarproduct_int16 |
| 95 | static inline int16_t *scalarproduct(const int16_t *in, const int16_t *endin, int16_t *out) |
| 96 | { |
| 97 | int32_t sample; |
| 98 | int16_t j; |
| 99 | |
| 100 | while (in < endin) { |
| 101 | sample = 0; |
| 102 | for (j = 0; j < NUMTAPS; j++) |
| 103 | sample += in[j] * filt[j]; |
| 104 | *out = av_clip_int16(sample >> 6); |
| 105 | out++; |
| 106 | in++; |
| 107 | } |
| 108 | |
| 109 | return out; |
| 110 | } |
| 111 | |
| 112 | static int filter_frame(AVFilterLink *inlink, AVFrame *insamples) |
| 113 | { |
| 114 | AVFilterLink *outlink = inlink->dst->outputs[0]; |
| 115 | int16_t *taps, *endin, *in, *out; |
| 116 | AVFrame *outsamples = ff_get_audio_buffer(inlink, insamples->nb_samples); |
| 117 | int len; |
| 118 | |
| 119 | if (!outsamples) { |
| 120 | av_frame_free(&insamples); |
| 121 | return AVERROR(ENOMEM); |
| 122 | } |
| 123 | av_frame_copy_props(outsamples, insamples); |
| 124 | |
| 125 | taps = ((EarwaxContext *)inlink->dst->priv)->taps; |
| 126 | out = (int16_t *)outsamples->data[0]; |
| 127 | in = (int16_t *)insamples ->data[0]; |
| 128 | |
| 129 | len = FFMIN(NUMTAPS, 2*insamples->nb_samples); |
| 130 | // copy part of new input and process with saved input |
| 131 | memcpy(taps+NUMTAPS, in, len * sizeof(*taps)); |
| 132 | out = scalarproduct(taps, taps + len, out); |
| 133 | |
| 134 | // process current input |
| 135 | if (2*insamples->nb_samples >= NUMTAPS ){ |
| 136 | endin = in + insamples->nb_samples * 2 - NUMTAPS; |
| 137 | scalarproduct(in, endin, out); |
| 138 | |
| 139 | // save part of input for next round |
| 140 | memcpy(taps, endin, NUMTAPS * sizeof(*taps)); |
| 141 | } else |
| 142 | memmove(taps, taps + 2*insamples->nb_samples, NUMTAPS * sizeof(*taps)); |
| 143 | |
| 144 | av_frame_free(&insamples); |
| 145 | return ff_filter_frame(outlink, outsamples); |
| 146 | } |
| 147 | |
| 148 | static const AVFilterPad earwax_inputs[] = { |
| 149 | { |
| 150 | .name = "default", |
| 151 | .type = AVMEDIA_TYPE_AUDIO, |
| 152 | .filter_frame = filter_frame, |
| 153 | }, |
| 154 | { NULL } |
| 155 | }; |
| 156 | |
| 157 | static const AVFilterPad earwax_outputs[] = { |
| 158 | { |
| 159 | .name = "default", |
| 160 | .type = AVMEDIA_TYPE_AUDIO, |
| 161 | }, |
| 162 | { NULL } |
| 163 | }; |
| 164 | |
| 165 | AVFilter ff_af_earwax = { |
| 166 | .name = "earwax", |
| 167 | .description = NULL_IF_CONFIG_SMALL("Widen the stereo image."), |
| 168 | .query_formats = query_formats, |
| 169 | .priv_size = sizeof(EarwaxContext), |
| 170 | .inputs = earwax_inputs, |
| 171 | .outputs = earwax_outputs, |
| 172 | }; |