2 * Copyright (c) 2016 Paul B Mahol
4 * This file is part of FFmpeg.
6 * FFmpeg is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU Lesser General Public License as published
8 * by the Free Software Foundation; either version 2.1 of the License,
9 * or (at your option) any later version.
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.
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
21 #include "libavutil/audio_fifo.h"
22 #include "libavutil/avstring.h"
23 #include "libavfilter/internal.h"
24 #include "libavutil/common.h"
25 #include "libavutil/opt.h"
26 #include "libavcodec/avfft.h"
27 #include "libavutil/eval.h"
29 #include "window_func.h"
31 typedef struct AFFTFiltContext {
37 FFTContext *fft, *ifft;
38 FFTComplex **fft_data;
51 float *window_func_lut;
54 static const char *const var_names[] = { "sr", "b", "nb", "ch", "chs", "pts", NULL };
55 enum { VAR_SAMPLE_RATE, VAR_BIN, VAR_NBBINS, VAR_CHANNEL, VAR_CHANNELS, VAR_PTS, VAR_VARS_NB };
57 #define OFFSET(x) offsetof(AFFTFiltContext, x)
58 #define A AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
60 static const AVOption afftfilt_options[] = {
61 { "real", "set channels real expressions", OFFSET(real_str), AV_OPT_TYPE_STRING, {.str = "1" }, 0, 0, A },
62 { "imag", "set channels imaginary expressions", OFFSET(img_str), AV_OPT_TYPE_STRING, {.str = NULL }, 0, 0, A },
63 { "win_size", "set window size", OFFSET(fft_bits), AV_OPT_TYPE_INT, {.i64=12}, 4, 16, A, "fft" },
64 { "w16", 0, 0, AV_OPT_TYPE_CONST, {.i64=4}, 0, 0, A, "fft" },
65 { "w32", 0, 0, AV_OPT_TYPE_CONST, {.i64=5}, 0, 0, A, "fft" },
66 { "w64", 0, 0, AV_OPT_TYPE_CONST, {.i64=6}, 0, 0, A, "fft" },
67 { "w128", 0, 0, AV_OPT_TYPE_CONST, {.i64=7}, 0, 0, A, "fft" },
68 { "w256", 0, 0, AV_OPT_TYPE_CONST, {.i64=8}, 0, 0, A, "fft" },
69 { "w512", 0, 0, AV_OPT_TYPE_CONST, {.i64=9}, 0, 0, A, "fft" },
70 { "w1024", 0, 0, AV_OPT_TYPE_CONST, {.i64=10}, 0, 0, A, "fft" },
71 { "w2048", 0, 0, AV_OPT_TYPE_CONST, {.i64=11}, 0, 0, A, "fft" },
72 { "w4096", 0, 0, AV_OPT_TYPE_CONST, {.i64=12}, 0, 0, A, "fft" },
73 { "w8192", 0, 0, AV_OPT_TYPE_CONST, {.i64=13}, 0, 0, A, "fft" },
74 { "w16384", 0, 0, AV_OPT_TYPE_CONST, {.i64=14}, 0, 0, A, "fft" },
75 { "w32768", 0, 0, AV_OPT_TYPE_CONST, {.i64=15}, 0, 0, A, "fft" },
76 { "w65536", 0, 0, AV_OPT_TYPE_CONST, {.i64=16}, 0, 0, A, "fft" },
77 { "win_func", "set window function", OFFSET(win_func), AV_OPT_TYPE_INT, {.i64 = WFUNC_HANNING}, 0, NB_WFUNC-1, A, "win_func" },
78 { "rect", "Rectangular", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_RECT}, 0, 0, A, "win_func" },
79 { "bartlett", "Bartlett", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_BARTLETT}, 0, 0, A, "win_func" },
80 { "hann", "Hann", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING}, 0, 0, A, "win_func" },
81 { "hanning", "Hanning", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HANNING}, 0, 0, A, "win_func" },
82 { "hamming", "Hamming", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_HAMMING}, 0, 0, A, "win_func" },
83 { "sine", "Sine", 0, AV_OPT_TYPE_CONST, {.i64=WFUNC_SINE}, 0, 0, A, "win_func" },
84 { "overlap", "set window overlap", OFFSET(overlap), AV_OPT_TYPE_FLOAT, {.dbl=0.75}, 0, 1, A },
88 AVFILTER_DEFINE_CLASS(afftfilt);
90 static int config_input(AVFilterLink *inlink)
92 AVFilterContext *ctx = inlink->dst;
93 AFFTFiltContext *s = ctx->priv;
98 const char *last_expr = "1";
100 s->fft = av_fft_init(s->fft_bits, 0);
101 s->ifft = av_fft_init(s->fft_bits, 1);
102 if (!s->fft || !s->ifft)
103 return AVERROR(ENOMEM);
105 s->window_size = 1 << s->fft_bits;
107 s->fft_data = av_calloc(inlink->channels, sizeof(*s->fft_data));
109 return AVERROR(ENOMEM);
111 for (ch = 0; ch < inlink->channels; ch++) {
112 s->fft_data[ch] = av_calloc(s->window_size, sizeof(**s->fft_data));
113 if (!s->fft_data[ch])
114 return AVERROR(ENOMEM);
117 s->real = av_calloc(inlink->channels, sizeof(*s->real));
119 return AVERROR(ENOMEM);
121 s->imag = av_calloc(inlink->channels, sizeof(*s->imag));
123 return AVERROR(ENOMEM);
125 args = av_strdup(s->real_str);
127 return AVERROR(ENOMEM);
129 for (ch = 0; ch < inlink->channels; ch++) {
130 char *arg = av_strtok(ch == 0 ? args : NULL, "|", &saveptr);
132 ret = av_expr_parse(&s->real[ch], arg ? arg : last_expr, var_names,
133 NULL, NULL, NULL, NULL, 0, ctx);
143 args = av_strdup(s->img_str ? s->img_str : s->real_str);
145 return AVERROR(ENOMEM);
147 for (ch = 0; ch < inlink->channels; ch++) {
148 char *arg = av_strtok(ch == 0 ? args : NULL, "|", &saveptr);
150 ret = av_expr_parse(&s->imag[ch], arg ? arg : last_expr, var_names,
151 NULL, NULL, NULL, NULL, 0, ctx);
160 s->fifo = av_audio_fifo_alloc(inlink->format, inlink->channels, s->window_size);
162 return AVERROR(ENOMEM);
164 s->window_func_lut = av_realloc_f(s->window_func_lut, s->window_size,
165 sizeof(*s->window_func_lut));
166 if (!s->window_func_lut)
167 return AVERROR(ENOMEM);
168 ff_generate_window_func(s->window_func_lut, s->window_size, s->win_func, &overlap);
170 s->overlap = overlap;
172 for (s->win_scale = 0, i = 0; i < s->window_size; i++) {
173 s->win_scale += s->window_func_lut[i] * s->window_func_lut[i];
176 s->hop_size = s->window_size * (1 - s->overlap);
177 if (s->hop_size <= 0)
178 return AVERROR(EINVAL);
180 s->buffer = ff_get_audio_buffer(inlink, s->window_size * 2);
182 return AVERROR(ENOMEM);
187 static int filter_frame(AVFilterLink *inlink, AVFrame *frame)
189 AVFilterContext *ctx = inlink->dst;
190 AVFilterLink *outlink = ctx->outputs[0];
191 AFFTFiltContext *s = ctx->priv;
192 const int window_size = s->window_size;
193 const float f = 1. / s->win_scale;
194 double values[VAR_VARS_NB];
195 AVFrame *out, *in = NULL;
196 int ch, n, ret, i, j, k;
197 int start = s->start, end = s->end;
199 av_audio_fifo_write(s->fifo, (void **)frame->extended_data, frame->nb_samples);
200 av_frame_free(&frame);
202 while (av_audio_fifo_size(s->fifo) >= window_size) {
204 in = ff_get_audio_buffer(outlink, window_size);
206 return AVERROR(ENOMEM);
209 ret = av_audio_fifo_peek(s->fifo, (void **)in->extended_data, window_size);
213 for (ch = 0; ch < inlink->channels; ch++) {
214 const float *src = (float *)in->extended_data[ch];
215 FFTComplex *fft_data = s->fft_data[ch];
217 for (n = 0; n < in->nb_samples; n++) {
218 fft_data[n].re = src[n] * s->window_func_lut[n];
222 for (; n < window_size; n++) {
228 values[VAR_PTS] = s->pts;
229 values[VAR_SAMPLE_RATE] = inlink->sample_rate;
230 values[VAR_NBBINS] = window_size / 2;
231 values[VAR_CHANNELS] = inlink->channels;
233 for (ch = 0; ch < inlink->channels; ch++) {
234 FFTComplex *fft_data = s->fft_data[ch];
235 float *buf = (float *)s->buffer->extended_data[ch];
238 values[VAR_CHANNEL] = ch;
240 av_fft_permute(s->fft, fft_data);
241 av_fft_calc(s->fft, fft_data);
243 for (n = 0; n < window_size / 2; n++) {
248 fr = av_expr_eval(s->real[ch], values, s);
249 fi = av_expr_eval(s->imag[ch], values, s);
251 fft_data[n].re *= fr;
252 fft_data[n].im *= fi;
255 for (n = window_size / 2 + 1, x = window_size / 2 - 1; n < window_size; n++, x--) {
256 fft_data[n].re = fft_data[x].re;
257 fft_data[n].im = -fft_data[x].im;
260 av_fft_permute(s->ifft, fft_data);
261 av_fft_calc(s->ifft, fft_data);
266 for (i = 0, j = start; j < k && i < window_size; i++, j++) {
267 buf[j] += s->fft_data[ch][i].re * f;
270 for (; i < window_size; i++, j++) {
271 buf[j] = s->fft_data[ch][i].re * f;
274 start += s->hop_size;
281 if (start >= window_size) {
284 start -= window_size;
290 out = ff_get_audio_buffer(outlink, window_size);
292 ret = AVERROR(ENOMEM);
297 s->pts += window_size;
299 for (ch = 0; ch < inlink->channels; ch++) {
300 dst = (float *)out->extended_data[ch];
301 buf = (float *)s->buffer->extended_data[ch];
303 for (n = 0; n < window_size; n++) {
304 dst[n] = buf[n] * (1 - s->overlap);
306 memmove(buf, buf + window_size, window_size * 4);
309 ret = ff_filter_frame(outlink, out);
314 av_audio_fifo_drain(s->fifo, s->hop_size);
321 static int query_formats(AVFilterContext *ctx)
323 AVFilterFormats *formats;
324 AVFilterChannelLayouts *layouts;
325 static const enum AVSampleFormat sample_fmts[] = {
331 layouts = ff_all_channel_counts();
333 return AVERROR(ENOMEM);
334 ret = ff_set_common_channel_layouts(ctx, layouts);
338 formats = ff_make_format_list(sample_fmts);
340 return AVERROR(ENOMEM);
341 ret = ff_set_common_formats(ctx, formats);
345 formats = ff_all_samplerates();
347 return AVERROR(ENOMEM);
348 return ff_set_common_samplerates(ctx, formats);
351 static av_cold void uninit(AVFilterContext *ctx)
353 AFFTFiltContext *s = ctx->priv;
359 for (i = 0; i < s->nb_exprs; i++) {
361 av_freep(&s->fft_data[i]);
363 av_freep(&s->fft_data);
365 for (i = 0; i < s->nb_exprs; i++) {
366 av_expr_free(s->real[i]);
367 av_expr_free(s->imag[i]);
372 av_frame_free(&s->buffer);
375 static const AVFilterPad inputs[] = {
378 .type = AVMEDIA_TYPE_AUDIO,
379 .config_props = config_input,
380 .filter_frame = filter_frame,
385 static const AVFilterPad outputs[] = {
388 .type = AVMEDIA_TYPE_AUDIO,
393 AVFilter ff_af_afftfilt = {
395 .description = NULL_IF_CONFIG_SMALL("Apply arbitrary expressions to samples in frequency domain."),
396 .priv_size = sizeof(AFFTFiltContext),
397 .priv_class = &afftfilt_class,
400 .query_formats = query_formats,