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1 | /* |
2 | * Copyright (c) 2006 Rob Sykes <robs@users.sourceforge.net> | |
3 | * | |
4 | * This file is part of FFmpeg. | |
5 | * | |
6 | * FFmpeg is free software; you can redistribute it and/or | |
7 | * modify it under the terms of the GNU Lesser General Public | |
8 | * License as published by the Free Software Foundation; either | |
9 | * version 2.1 of the License, or (at your option) any later version. | |
10 | * | |
11 | * FFmpeg is distributed in the hope that it will be useful, | |
12 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
13 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
14 | * Lesser General Public License for more details. | |
15 | * | |
16 | * You should have received a copy of the GNU Lesser General Public | |
17 | * License along with FFmpeg; if not, write to the Free Software | |
18 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
19 | */ | |
20 | ||
21 | #include "libavutil/avstring.h" | |
22 | #include "libavutil/opt.h" | |
23 | #include "libavutil/samplefmt.h" | |
24 | #include "avfilter.h" | |
25 | #include "audio.h" | |
26 | #include "internal.h" | |
27 | #include "generate_wave_table.h" | |
28 | ||
29 | #define INTERPOLATION_LINEAR 0 | |
30 | #define INTERPOLATION_QUADRATIC 1 | |
31 | ||
32 | typedef struct FlangerContext { | |
33 | const AVClass *class; | |
34 | double delay_min; | |
35 | double delay_depth; | |
36 | double feedback_gain; | |
37 | double delay_gain; | |
38 | double speed; | |
39 | int wave_shape; | |
40 | double channel_phase; | |
41 | int interpolation; | |
42 | double in_gain; | |
43 | int max_samples; | |
44 | uint8_t **delay_buffer; | |
45 | int delay_buf_pos; | |
46 | double *delay_last; | |
47 | float *lfo; | |
48 | int lfo_length; | |
49 | int lfo_pos; | |
50 | } FlangerContext; | |
51 | ||
52 | #define OFFSET(x) offsetof(FlangerContext, x) | |
53 | #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM | |
54 | ||
55 | static const AVOption flanger_options[] = { | |
56 | { "delay", "base delay in milliseconds", OFFSET(delay_min), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 30, A }, | |
57 | { "depth", "added swept delay in milliseconds", OFFSET(delay_depth), AV_OPT_TYPE_DOUBLE, {.dbl=2}, 0, 10, A }, | |
58 | { "regen", "percentage regeneration (delayed signal feedback)", OFFSET(feedback_gain), AV_OPT_TYPE_DOUBLE, {.dbl=0}, -95, 95, A }, | |
59 | { "width", "percentage of delayed signal mixed with original", OFFSET(delay_gain), AV_OPT_TYPE_DOUBLE, {.dbl=71}, 0, 100, A }, | |
60 | { "speed", "sweeps per second (Hz)", OFFSET(speed), AV_OPT_TYPE_DOUBLE, {.dbl=0.5}, 0.1, 10, A }, | |
61 | { "shape", "swept wave shape", OFFSET(wave_shape), AV_OPT_TYPE_INT, {.i64=WAVE_SIN}, WAVE_SIN, WAVE_NB-1, A, "type" }, | |
62 | { "triangular", NULL, 0, AV_OPT_TYPE_CONST, {.i64=WAVE_TRI}, 0, 0, A, "type" }, | |
63 | { "t", NULL, 0, AV_OPT_TYPE_CONST, {.i64=WAVE_TRI}, 0, 0, A, "type" }, | |
64 | { "sinusoidal", NULL, 0, AV_OPT_TYPE_CONST, {.i64=WAVE_SIN}, 0, 0, A, "type" }, | |
65 | { "s", NULL, 0, AV_OPT_TYPE_CONST, {.i64=WAVE_SIN}, 0, 0, A, "type" }, | |
66 | { "phase", "swept wave percentage phase-shift for multi-channel", OFFSET(channel_phase), AV_OPT_TYPE_DOUBLE, {.dbl=25}, 0, 100, A }, | |
67 | { "interp", "delay-line interpolation", OFFSET(interpolation), AV_OPT_TYPE_INT, {.i64=0}, 0, 1, A, "itype" }, | |
68 | { "linear", NULL, 0, AV_OPT_TYPE_CONST, {.i64=INTERPOLATION_LINEAR}, 0, 0, A, "itype" }, | |
69 | { "quadratic", NULL, 0, AV_OPT_TYPE_CONST, {.i64=INTERPOLATION_QUADRATIC}, 0, 0, A, "itype" }, | |
70 | { NULL } | |
71 | }; | |
72 | ||
73 | AVFILTER_DEFINE_CLASS(flanger); | |
74 | ||
75 | static int init(AVFilterContext *ctx) | |
76 | { | |
77 | FlangerContext *s = ctx->priv; | |
78 | ||
79 | s->feedback_gain /= 100; | |
80 | s->delay_gain /= 100; | |
81 | s->channel_phase /= 100; | |
82 | s->delay_min /= 1000; | |
83 | s->delay_depth /= 1000; | |
84 | s->in_gain = 1 / (1 + s->delay_gain); | |
85 | s->delay_gain /= 1 + s->delay_gain; | |
86 | s->delay_gain *= 1 - fabs(s->feedback_gain); | |
87 | ||
88 | return 0; | |
89 | } | |
90 | ||
91 | static int query_formats(AVFilterContext *ctx) | |
92 | { | |
93 | AVFilterChannelLayouts *layouts; | |
94 | AVFilterFormats *formats; | |
95 | static const enum AVSampleFormat sample_fmts[] = { | |
96 | AV_SAMPLE_FMT_DBLP, AV_SAMPLE_FMT_NONE | |
97 | }; | |
98 | ||
99 | layouts = ff_all_channel_layouts(); | |
100 | if (!layouts) | |
101 | return AVERROR(ENOMEM); | |
102 | ff_set_common_channel_layouts(ctx, layouts); | |
103 | ||
104 | formats = ff_make_format_list(sample_fmts); | |
105 | if (!formats) | |
106 | return AVERROR(ENOMEM); | |
107 | ff_set_common_formats(ctx, formats); | |
108 | ||
109 | formats = ff_all_samplerates(); | |
110 | if (!formats) | |
111 | return AVERROR(ENOMEM); | |
112 | ff_set_common_samplerates(ctx, formats); | |
113 | ||
114 | return 0; | |
115 | } | |
116 | ||
117 | static int config_input(AVFilterLink *inlink) | |
118 | { | |
119 | AVFilterContext *ctx = inlink->dst; | |
120 | FlangerContext *s = ctx->priv; | |
121 | ||
122 | s->max_samples = (s->delay_min + s->delay_depth) * inlink->sample_rate + 2.5; | |
123 | s->lfo_length = inlink->sample_rate / s->speed; | |
124 | s->delay_last = av_calloc(inlink->channels, sizeof(*s->delay_last)); | |
125 | s->lfo = av_calloc(s->lfo_length, sizeof(*s->lfo)); | |
126 | if (!s->lfo || !s->delay_last) | |
127 | return AVERROR(ENOMEM); | |
128 | ||
129 | ff_generate_wave_table(s->wave_shape, AV_SAMPLE_FMT_FLT, s->lfo, s->lfo_length, | |
130 | floor(s->delay_min * inlink->sample_rate + 0.5), | |
131 | s->max_samples - 2., 3 * M_PI_2); | |
132 | ||
133 | return av_samples_alloc_array_and_samples(&s->delay_buffer, NULL, | |
134 | inlink->channels, s->max_samples, | |
135 | inlink->format, 0); | |
136 | } | |
137 | ||
138 | static int filter_frame(AVFilterLink *inlink, AVFrame *frame) | |
139 | { | |
140 | AVFilterContext *ctx = inlink->dst; | |
141 | FlangerContext *s = ctx->priv; | |
142 | AVFrame *out_frame; | |
143 | int chan, i; | |
144 | ||
145 | if (av_frame_is_writable(frame)) { | |
146 | out_frame = frame; | |
147 | } else { | |
148 | out_frame = ff_get_audio_buffer(inlink, frame->nb_samples); | |
149 | if (!out_frame) | |
150 | return AVERROR(ENOMEM); | |
151 | av_frame_copy_props(out_frame, frame); | |
152 | } | |
153 | ||
154 | for (i = 0; i < frame->nb_samples; i++) { | |
155 | ||
156 | s->delay_buf_pos = (s->delay_buf_pos + s->max_samples - 1) % s->max_samples; | |
157 | ||
158 | for (chan = 0; chan < inlink->channels; chan++) { | |
159 | double *src = (double *)frame->extended_data[chan]; | |
160 | double *dst = (double *)out_frame->extended_data[chan]; | |
161 | double delayed_0, delayed_1; | |
162 | double delayed; | |
163 | double in, out; | |
164 | int channel_phase = chan * s->lfo_length * s->channel_phase + .5; | |
165 | double delay = s->lfo[(s->lfo_pos + channel_phase) % s->lfo_length]; | |
166 | int int_delay = (int)delay; | |
167 | double frac_delay = modf(delay, &delay); | |
168 | double *delay_buffer = (double *)s->delay_buffer[chan]; | |
169 | ||
170 | in = src[i]; | |
171 | delay_buffer[s->delay_buf_pos] = in + s->delay_last[chan] * | |
172 | s->feedback_gain; | |
173 | delayed_0 = delay_buffer[(s->delay_buf_pos + int_delay++) % s->max_samples]; | |
174 | delayed_1 = delay_buffer[(s->delay_buf_pos + int_delay++) % s->max_samples]; | |
175 | ||
176 | if (s->interpolation == INTERPOLATION_LINEAR) { | |
177 | delayed = delayed_0 + (delayed_1 - delayed_0) * frac_delay; | |
178 | } else { | |
179 | double a, b; | |
180 | double delayed_2 = delay_buffer[(s->delay_buf_pos + int_delay++) % s->max_samples]; | |
181 | delayed_2 -= delayed_0; | |
182 | delayed_1 -= delayed_0; | |
183 | a = delayed_2 * .5 - delayed_1; | |
184 | b = delayed_1 * 2 - delayed_2 *.5; | |
185 | delayed = delayed_0 + (a * frac_delay + b) * frac_delay; | |
186 | } | |
187 | ||
188 | s->delay_last[chan] = delayed; | |
189 | out = in * s->in_gain + delayed * s->delay_gain; | |
190 | dst[i] = out; | |
191 | } | |
192 | s->lfo_pos = (s->lfo_pos + 1) % s->lfo_length; | |
193 | } | |
194 | ||
195 | if (frame != out_frame) | |
196 | av_frame_free(&frame); | |
197 | ||
198 | return ff_filter_frame(ctx->outputs[0], out_frame); | |
199 | } | |
200 | ||
201 | static av_cold void uninit(AVFilterContext *ctx) | |
202 | { | |
203 | FlangerContext *s = ctx->priv; | |
204 | ||
205 | av_freep(&s->lfo); | |
206 | av_freep(&s->delay_last); | |
207 | ||
208 | if (s->delay_buffer) | |
209 | av_freep(&s->delay_buffer[0]); | |
210 | av_freep(&s->delay_buffer); | |
211 | } | |
212 | ||
213 | static const AVFilterPad flanger_inputs[] = { | |
214 | { | |
215 | .name = "default", | |
216 | .type = AVMEDIA_TYPE_AUDIO, | |
217 | .config_props = config_input, | |
218 | .filter_frame = filter_frame, | |
219 | }, | |
220 | { NULL } | |
221 | }; | |
222 | ||
223 | static const AVFilterPad flanger_outputs[] = { | |
224 | { | |
225 | .name = "default", | |
226 | .type = AVMEDIA_TYPE_AUDIO, | |
227 | }, | |
228 | { NULL } | |
229 | }; | |
230 | ||
231 | AVFilter ff_af_flanger = { | |
232 | .name = "flanger", | |
233 | .description = NULL_IF_CONFIG_SMALL("Apply a flanging effect to the audio."), | |
234 | .query_formats = query_formats, | |
235 | .priv_size = sizeof(FlangerContext), | |
236 | .priv_class = &flanger_class, | |
237 | .init = init, | |
238 | .uninit = uninit, | |
239 | .inputs = flanger_inputs, | |
240 | .outputs = flanger_outputs, | |
241 | }; |