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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 | }; |