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1 /*
2  * Copyright (c) 2013-2015 Paul B Mahol
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 /**
22  * @file
23  * fade audio filter
24  */
25 
26 #include "config_components.h"
27 
28 #include "libavutil/opt.h"
29 #include "audio.h"
30 #include "avfilter.h"
31 #include "filters.h"
32 #include "internal.h"
33 
34 typedef struct AudioFadeContext {
35     const AVClass *class;
36     int type;
37     int curve, curve2;
38     int64_t nb_samples;
39     int64_t start_sample;
40     int64_t duration;
41     int64_t start_time;
42     int overlap;
43     int cf0_eof;
44     int crossfade_is_over;
45     int64_t pts;
46 
47     void (*fade_samples)(uint8_t **dst, uint8_t * const *src,
48                          int nb_samples, int channels, int direction,
49                          int64_t start, int64_t range, int curve);
50     void (*crossfade_samples)(uint8_t **dst, uint8_t * const *cf0,
51                               uint8_t * const *cf1,
52                               int nb_samples, int channels,
53                               int curve0, int curve1);
54 } AudioFadeContext;
55 
56 enum CurveType { NONE = -1, TRI, QSIN, ESIN, HSIN, LOG, IPAR, QUA, CUB, SQU, CBR, PAR, EXP, IQSIN, IHSIN, DESE, DESI, LOSI, SINC, ISINC, NB_CURVES };
57 
58 #define OFFSET(x) offsetof(AudioFadeContext, x)
59 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
60 #define TFLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM
61 
62     static const enum AVSampleFormat sample_fmts[] = {
63         AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P,
64         AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
65         AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
66         AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
67         AV_SAMPLE_FMT_NONE
68     };
69 
fade_gain(int curve,int64_t index,int64_t range)70 static double fade_gain(int curve, int64_t index, int64_t range)
71 {
72 #define CUBE(a) ((a)*(a)*(a))
73     double gain;
74 
75     gain = av_clipd(1.0 * index / range, 0, 1.0);
76 
77     switch (curve) {
78     case QSIN:
79         gain = sin(gain * M_PI / 2.0);
80         break;
81     case IQSIN:
82         /* 0.6... = 2 / M_PI */
83         gain = 0.6366197723675814 * asin(gain);
84         break;
85     case ESIN:
86         gain = 1.0 - cos(M_PI / 4.0 * (CUBE(2.0*gain - 1) + 1));
87         break;
88     case HSIN:
89         gain = (1.0 - cos(gain * M_PI)) / 2.0;
90         break;
91     case IHSIN:
92         /* 0.3... = 1 / M_PI */
93         gain = 0.3183098861837907 * acos(1 - 2 * gain);
94         break;
95     case EXP:
96         /* -11.5... = 5*ln(0.1) */
97         gain = exp(-11.512925464970227 * (1 - gain));
98         break;
99     case LOG:
100         gain = av_clipd(1 + 0.2 * log10(gain), 0, 1.0);
101         break;
102     case PAR:
103         gain = 1 - sqrt(1 - gain);
104         break;
105     case IPAR:
106         gain = (1 - (1 - gain) * (1 - gain));
107         break;
108     case QUA:
109         gain *= gain;
110         break;
111     case CUB:
112         gain = CUBE(gain);
113         break;
114     case SQU:
115         gain = sqrt(gain);
116         break;
117     case CBR:
118         gain = cbrt(gain);
119         break;
120     case DESE:
121         gain = gain <= 0.5 ? cbrt(2 * gain) / 2: 1 - cbrt(2 * (1 - gain)) / 2;
122         break;
123     case DESI:
124         gain = gain <= 0.5 ? CUBE(2 * gain) / 2: 1 - CUBE(2 * (1 - gain)) / 2;
125         break;
126     case LOSI: {
127                    const double a = 1. / (1. - 0.787) - 1;
128                    double A = 1. / (1.0 + exp(0 -((gain-0.5) * a * 2.0)));
129                    double B = 1. / (1.0 + exp(a));
130                    double C = 1. / (1.0 + exp(0-a));
131                    gain = (A - B) / (C - B);
132                }
133         break;
134     case SINC:
135         gain = gain >= 1.0 ? 1.0 : sin(M_PI * (1.0 - gain)) / (M_PI * (1.0 - gain));
136         break;
137     case ISINC:
138         gain = gain <= 0.0 ? 0.0 : 1.0 - sin(M_PI * gain) / (M_PI * gain);
139         break;
140     case NONE:
141         gain = 1.0;
142         break;
143     }
144 
145     return gain;
146 }
147 
148 #define FADE_PLANAR(name, type)                                             \
149 static void fade_samples_## name ##p(uint8_t **dst, uint8_t * const *src,   \
150                                      int nb_samples, int channels, int dir, \
151                                      int64_t start, int64_t range, int curve) \
152 {                                                                           \
153     int i, c;                                                               \
154                                                                             \
155     for (i = 0; i < nb_samples; i++) {                                      \
156         double gain = fade_gain(curve, start + i * dir, range);             \
157         for (c = 0; c < channels; c++) {                                    \
158             type *d = (type *)dst[c];                                       \
159             const type *s = (type *)src[c];                                 \
160                                                                             \
161             d[i] = s[i] * gain;                                             \
162         }                                                                   \
163     }                                                                       \
164 }
165 
166 #define FADE(name, type)                                                    \
167 static void fade_samples_## name (uint8_t **dst, uint8_t * const *src,      \
168                                   int nb_samples, int channels, int dir,    \
169                                   int64_t start, int64_t range, int curve)  \
170 {                                                                           \
171     type *d = (type *)dst[0];                                               \
172     const type *s = (type *)src[0];                                         \
173     int i, c, k = 0;                                                        \
174                                                                             \
175     for (i = 0; i < nb_samples; i++) {                                      \
176         double gain = fade_gain(curve, start + i * dir, range);             \
177         for (c = 0; c < channels; c++, k++)                                 \
178             d[k] = s[k] * gain;                                             \
179     }                                                                       \
180 }
181 
FADE_PLANAR(dbl,double)182 FADE_PLANAR(dbl, double)
183 FADE_PLANAR(flt, float)
184 FADE_PLANAR(s16, int16_t)
185 FADE_PLANAR(s32, int32_t)
186 
187 FADE(dbl, double)
188 FADE(flt, float)
189 FADE(s16, int16_t)
190 FADE(s32, int32_t)
191 
192 static int config_output(AVFilterLink *outlink)
193 {
194     AVFilterContext *ctx = outlink->src;
195     AudioFadeContext *s  = ctx->priv;
196 
197     switch (outlink->format) {
198     case AV_SAMPLE_FMT_DBL:  s->fade_samples = fade_samples_dbl;  break;
199     case AV_SAMPLE_FMT_DBLP: s->fade_samples = fade_samples_dblp; break;
200     case AV_SAMPLE_FMT_FLT:  s->fade_samples = fade_samples_flt;  break;
201     case AV_SAMPLE_FMT_FLTP: s->fade_samples = fade_samples_fltp; break;
202     case AV_SAMPLE_FMT_S16:  s->fade_samples = fade_samples_s16;  break;
203     case AV_SAMPLE_FMT_S16P: s->fade_samples = fade_samples_s16p; break;
204     case AV_SAMPLE_FMT_S32:  s->fade_samples = fade_samples_s32;  break;
205     case AV_SAMPLE_FMT_S32P: s->fade_samples = fade_samples_s32p; break;
206     }
207 
208     if (s->duration)
209         s->nb_samples = av_rescale(s->duration, outlink->sample_rate, AV_TIME_BASE);
210     s->duration = 0;
211     if (s->start_time)
212         s->start_sample = av_rescale(s->start_time, outlink->sample_rate, AV_TIME_BASE);
213     s->start_time = 0;
214 
215     return 0;
216 }
217 
218 #if CONFIG_AFADE_FILTER
219 
220 static const AVOption afade_options[] = {
221     { "type",         "set the fade direction",                      OFFSET(type),         AV_OPT_TYPE_INT,    {.i64 = 0    }, 0, 1, TFLAGS, "type" },
222     { "t",            "set the fade direction",                      OFFSET(type),         AV_OPT_TYPE_INT,    {.i64 = 0    }, 0, 1, TFLAGS, "type" },
223     { "in",           "fade-in",                                     0,                    AV_OPT_TYPE_CONST,  {.i64 = 0    }, 0, 0, TFLAGS, "type" },
224     { "out",          "fade-out",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = 1    }, 0, 0, TFLAGS, "type" },
225     { "start_sample", "set number of first sample to start fading",  OFFSET(start_sample), AV_OPT_TYPE_INT64,  {.i64 = 0    }, 0, INT64_MAX, TFLAGS },
226     { "ss",           "set number of first sample to start fading",  OFFSET(start_sample), AV_OPT_TYPE_INT64,  {.i64 = 0    }, 0, INT64_MAX, TFLAGS },
227     { "nb_samples",   "set number of samples for fade duration",     OFFSET(nb_samples),   AV_OPT_TYPE_INT64,  {.i64 = 44100}, 1, INT64_MAX, TFLAGS },
228     { "ns",           "set number of samples for fade duration",     OFFSET(nb_samples),   AV_OPT_TYPE_INT64,  {.i64 = 44100}, 1, INT64_MAX, TFLAGS },
229     { "start_time",   "set time to start fading",                    OFFSET(start_time),   AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, INT64_MAX, TFLAGS },
230     { "st",           "set time to start fading",                    OFFSET(start_time),   AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, INT64_MAX, TFLAGS },
231     { "duration",     "set fade duration",                           OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, INT64_MAX, TFLAGS },
232     { "d",            "set fade duration",                           OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, INT64_MAX, TFLAGS },
233     { "curve",        "set fade curve type",                         OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, TFLAGS, "curve" },
234     { "c",            "set fade curve type",                         OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, TFLAGS, "curve" },
235     { "nofade",       "no fade; keep audio as-is",                   0,                    AV_OPT_TYPE_CONST,  {.i64 = NONE }, 0, 0, TFLAGS, "curve" },
236     { "tri",          "linear slope",                                0,                    AV_OPT_TYPE_CONST,  {.i64 = TRI  }, 0, 0, TFLAGS, "curve" },
237     { "qsin",         "quarter of sine wave",                        0,                    AV_OPT_TYPE_CONST,  {.i64 = QSIN }, 0, 0, TFLAGS, "curve" },
238     { "esin",         "exponential sine wave",                       0,                    AV_OPT_TYPE_CONST,  {.i64 = ESIN }, 0, 0, TFLAGS, "curve" },
239     { "hsin",         "half of sine wave",                           0,                    AV_OPT_TYPE_CONST,  {.i64 = HSIN }, 0, 0, TFLAGS, "curve" },
240     { "log",          "logarithmic",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = LOG  }, 0, 0, TFLAGS, "curve" },
241     { "ipar",         "inverted parabola",                           0,                    AV_OPT_TYPE_CONST,  {.i64 = IPAR }, 0, 0, TFLAGS, "curve" },
242     { "qua",          "quadratic",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = QUA  }, 0, 0, TFLAGS, "curve" },
243     { "cub",          "cubic",                                       0,                    AV_OPT_TYPE_CONST,  {.i64 = CUB  }, 0, 0, TFLAGS, "curve" },
244     { "squ",          "square root",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = SQU  }, 0, 0, TFLAGS, "curve" },
245     { "cbr",          "cubic root",                                  0,                    AV_OPT_TYPE_CONST,  {.i64 = CBR  }, 0, 0, TFLAGS, "curve" },
246     { "par",          "parabola",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = PAR  }, 0, 0, TFLAGS, "curve" },
247     { "exp",          "exponential",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = EXP  }, 0, 0, TFLAGS, "curve" },
248     { "iqsin",        "inverted quarter of sine wave",               0,                    AV_OPT_TYPE_CONST,  {.i64 = IQSIN}, 0, 0, TFLAGS, "curve" },
249     { "ihsin",        "inverted half of sine wave",                  0,                    AV_OPT_TYPE_CONST,  {.i64 = IHSIN}, 0, 0, TFLAGS, "curve" },
250     { "dese",         "double-exponential seat",                     0,                    AV_OPT_TYPE_CONST,  {.i64 = DESE }, 0, 0, TFLAGS, "curve" },
251     { "desi",         "double-exponential sigmoid",                  0,                    AV_OPT_TYPE_CONST,  {.i64 = DESI }, 0, 0, TFLAGS, "curve" },
252     { "losi",         "logistic sigmoid",                            0,                    AV_OPT_TYPE_CONST,  {.i64 = LOSI }, 0, 0, TFLAGS, "curve" },
253     { "sinc",         "sine cardinal function",                      0,                    AV_OPT_TYPE_CONST,  {.i64 = SINC }, 0, 0, TFLAGS, "curve" },
254     { "isinc",        "inverted sine cardinal function",             0,                    AV_OPT_TYPE_CONST,  {.i64 = ISINC}, 0, 0, TFLAGS, "curve" },
255     { NULL }
256 };
257 
258 AVFILTER_DEFINE_CLASS(afade);
259 
init(AVFilterContext * ctx)260 static av_cold int init(AVFilterContext *ctx)
261 {
262     AudioFadeContext *s = ctx->priv;
263 
264     if (INT64_MAX - s->nb_samples < s->start_sample)
265         return AVERROR(EINVAL);
266 
267     return 0;
268 }
269 
filter_frame(AVFilterLink * inlink,AVFrame * buf)270 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
271 {
272     AudioFadeContext *s     = inlink->dst->priv;
273     AVFilterLink *outlink   = inlink->dst->outputs[0];
274     int nb_samples          = buf->nb_samples;
275     AVFrame *out_buf;
276     int64_t cur_sample = av_rescale_q(buf->pts, inlink->time_base, (AVRational){1, inlink->sample_rate});
277 
278     if ((!s->type && (s->start_sample + s->nb_samples < cur_sample)) ||
279         ( s->type && (cur_sample + nb_samples < s->start_sample)))
280         return ff_filter_frame(outlink, buf);
281 
282     if (av_frame_is_writable(buf)) {
283         out_buf = buf;
284     } else {
285         out_buf = ff_get_audio_buffer(outlink, nb_samples);
286         if (!out_buf)
287             return AVERROR(ENOMEM);
288         av_frame_copy_props(out_buf, buf);
289     }
290 
291     if ((!s->type && (cur_sample + nb_samples < s->start_sample)) ||
292         ( s->type && (s->start_sample + s->nb_samples < cur_sample))) {
293         av_samples_set_silence(out_buf->extended_data, 0, nb_samples,
294                                out_buf->ch_layout.nb_channels, out_buf->format);
295     } else {
296         int64_t start;
297 
298         if (!s->type)
299             start = cur_sample - s->start_sample;
300         else
301             start = s->start_sample + s->nb_samples - cur_sample;
302 
303         s->fade_samples(out_buf->extended_data, buf->extended_data,
304                         nb_samples, buf->ch_layout.nb_channels,
305                         s->type ? -1 : 1, start,
306                         s->nb_samples, s->curve);
307     }
308 
309     if (buf != out_buf)
310         av_frame_free(&buf);
311 
312     return ff_filter_frame(outlink, out_buf);
313 }
314 
process_command(AVFilterContext * ctx,const char * cmd,const char * args,char * res,int res_len,int flags)315 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
316                            char *res, int res_len, int flags)
317 {
318     int ret;
319 
320     ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
321     if (ret < 0)
322         return ret;
323 
324     return config_output(ctx->outputs[0]);
325 }
326 
327 static const AVFilterPad avfilter_af_afade_inputs[] = {
328     {
329         .name         = "default",
330         .type         = AVMEDIA_TYPE_AUDIO,
331         .filter_frame = filter_frame,
332     },
333 };
334 
335 static const AVFilterPad avfilter_af_afade_outputs[] = {
336     {
337         .name         = "default",
338         .type         = AVMEDIA_TYPE_AUDIO,
339         .config_props = config_output,
340     },
341 };
342 
343 const AVFilter ff_af_afade = {
344     .name          = "afade",
345     .description   = NULL_IF_CONFIG_SMALL("Fade in/out input audio."),
346     .priv_size     = sizeof(AudioFadeContext),
347     .init          = init,
348     FILTER_INPUTS(avfilter_af_afade_inputs),
349     FILTER_OUTPUTS(avfilter_af_afade_outputs),
350     FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
351     .priv_class    = &afade_class,
352     .process_command = process_command,
353     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
354 };
355 
356 #endif /* CONFIG_AFADE_FILTER */
357 
358 #if CONFIG_ACROSSFADE_FILTER
359 
360 static const AVOption acrossfade_options[] = {
361     { "nb_samples",   "set number of samples for cross fade duration", OFFSET(nb_samples),   AV_OPT_TYPE_INT,    {.i64 = 44100}, 1, INT32_MAX/10, FLAGS },
362     { "ns",           "set number of samples for cross fade duration", OFFSET(nb_samples),   AV_OPT_TYPE_INT,    {.i64 = 44100}, 1, INT32_MAX/10, FLAGS },
363     { "duration",     "set cross fade duration",                       OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, 60000000, FLAGS },
364     { "d",            "set cross fade duration",                       OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0 },  0, 60000000, FLAGS },
365     { "overlap",      "overlap 1st stream end with 2nd stream start",  OFFSET(overlap),      AV_OPT_TYPE_BOOL,   {.i64 = 1    }, 0,  1, FLAGS },
366     { "o",            "overlap 1st stream end with 2nd stream start",  OFFSET(overlap),      AV_OPT_TYPE_BOOL,   {.i64 = 1    }, 0,  1, FLAGS },
367     { "curve1",       "set fade curve type for 1st stream",            OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, FLAGS, "curve" },
368     { "c1",           "set fade curve type for 1st stream",            OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, FLAGS, "curve" },
369     {     "nofade",   "no fade; keep audio as-is",                     0,                    AV_OPT_TYPE_CONST,  {.i64 = NONE }, 0, 0, FLAGS, "curve" },
370     {     "tri",      "linear slope",                                  0,                    AV_OPT_TYPE_CONST,  {.i64 = TRI  }, 0, 0, FLAGS, "curve" },
371     {     "qsin",     "quarter of sine wave",                          0,                    AV_OPT_TYPE_CONST,  {.i64 = QSIN }, 0, 0, FLAGS, "curve" },
372     {     "esin",     "exponential sine wave",                         0,                    AV_OPT_TYPE_CONST,  {.i64 = ESIN }, 0, 0, FLAGS, "curve" },
373     {     "hsin",     "half of sine wave",                             0,                    AV_OPT_TYPE_CONST,  {.i64 = HSIN }, 0, 0, FLAGS, "curve" },
374     {     "log",      "logarithmic",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = LOG  }, 0, 0, FLAGS, "curve" },
375     {     "ipar",     "inverted parabola",                             0,                    AV_OPT_TYPE_CONST,  {.i64 = IPAR }, 0, 0, FLAGS, "curve" },
376     {     "qua",      "quadratic",                                     0,                    AV_OPT_TYPE_CONST,  {.i64 = QUA  }, 0, 0, FLAGS, "curve" },
377     {     "cub",      "cubic",                                         0,                    AV_OPT_TYPE_CONST,  {.i64 = CUB  }, 0, 0, FLAGS, "curve" },
378     {     "squ",      "square root",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = SQU  }, 0, 0, FLAGS, "curve" },
379     {     "cbr",      "cubic root",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = CBR  }, 0, 0, FLAGS, "curve" },
380     {     "par",      "parabola",                                      0,                    AV_OPT_TYPE_CONST,  {.i64 = PAR  }, 0, 0, FLAGS, "curve" },
381     {     "exp",      "exponential",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = EXP  }, 0, 0, FLAGS, "curve" },
382     {     "iqsin",    "inverted quarter of sine wave",                 0,                    AV_OPT_TYPE_CONST,  {.i64 = IQSIN}, 0, 0, FLAGS, "curve" },
383     {     "ihsin",    "inverted half of sine wave",                    0,                    AV_OPT_TYPE_CONST,  {.i64 = IHSIN}, 0, 0, FLAGS, "curve" },
384     {     "dese",     "double-exponential seat",                       0,                    AV_OPT_TYPE_CONST,  {.i64 = DESE }, 0, 0, FLAGS, "curve" },
385     {     "desi",     "double-exponential sigmoid",                    0,                    AV_OPT_TYPE_CONST,  {.i64 = DESI }, 0, 0, FLAGS, "curve" },
386     {     "losi",     "logistic sigmoid",                              0,                    AV_OPT_TYPE_CONST,  {.i64 = LOSI }, 0, 0, FLAGS, "curve" },
387     {     "sinc",     "sine cardinal function",                        0,                    AV_OPT_TYPE_CONST,  {.i64 = SINC }, 0, 0, FLAGS, "curve" },
388     {     "isinc",    "inverted sine cardinal function",               0,                    AV_OPT_TYPE_CONST,  {.i64 = ISINC}, 0, 0, FLAGS, "curve" },
389     { "curve2",       "set fade curve type for 2nd stream",            OFFSET(curve2),       AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, FLAGS, "curve" },
390     { "c2",           "set fade curve type for 2nd stream",            OFFSET(curve2),       AV_OPT_TYPE_INT,    {.i64 = TRI  }, NONE, NB_CURVES - 1, FLAGS, "curve" },
391     { NULL }
392 };
393 
394 AVFILTER_DEFINE_CLASS(acrossfade);
395 
396 #define CROSSFADE_PLANAR(name, type)                                           \
397 static void crossfade_samples_## name ##p(uint8_t **dst, uint8_t * const *cf0, \
398                                           uint8_t * const *cf1,                \
399                                           int nb_samples, int channels,        \
400                                           int curve0, int curve1)              \
401 {                                                                              \
402     int i, c;                                                                  \
403                                                                                \
404     for (i = 0; i < nb_samples; i++) {                                         \
405         double gain0 = fade_gain(curve0, nb_samples - 1 - i, nb_samples);      \
406         double gain1 = fade_gain(curve1, i, nb_samples);                       \
407         for (c = 0; c < channels; c++) {                                       \
408             type *d = (type *)dst[c];                                          \
409             const type *s0 = (type *)cf0[c];                                   \
410             const type *s1 = (type *)cf1[c];                                   \
411                                                                                \
412             d[i] = s0[i] * gain0 + s1[i] * gain1;                              \
413         }                                                                      \
414     }                                                                          \
415 }
416 
417 #define CROSSFADE(name, type)                                               \
418 static void crossfade_samples_## name (uint8_t **dst, uint8_t * const *cf0, \
419                                        uint8_t * const *cf1,                \
420                                        int nb_samples, int channels,        \
421                                        int curve0, int curve1)              \
422 {                                                                           \
423     type *d = (type *)dst[0];                                               \
424     const type *s0 = (type *)cf0[0];                                        \
425     const type *s1 = (type *)cf1[0];                                        \
426     int i, c, k = 0;                                                        \
427                                                                             \
428     for (i = 0; i < nb_samples; i++) {                                      \
429         double gain0 = fade_gain(curve0, nb_samples - 1 - i, nb_samples);   \
430         double gain1 = fade_gain(curve1, i, nb_samples);                    \
431         for (c = 0; c < channels; c++, k++)                                 \
432             d[k] = s0[k] * gain0 + s1[k] * gain1;                           \
433     }                                                                       \
434 }
435 
CROSSFADE_PLANAR(dbl,double)436 CROSSFADE_PLANAR(dbl, double)
437 CROSSFADE_PLANAR(flt, float)
438 CROSSFADE_PLANAR(s16, int16_t)
439 CROSSFADE_PLANAR(s32, int32_t)
440 
441 CROSSFADE(dbl, double)
442 CROSSFADE(flt, float)
443 CROSSFADE(s16, int16_t)
444 CROSSFADE(s32, int32_t)
445 
446 static int activate(AVFilterContext *ctx)
447 {
448     AudioFadeContext *s   = ctx->priv;
449     AVFilterLink *outlink = ctx->outputs[0];
450     AVFrame *in = NULL, *out, *cf[2] = { NULL };
451     int ret = 0, nb_samples, status;
452     int64_t pts;
453 
454     FF_FILTER_FORWARD_STATUS_BACK_ALL(outlink, ctx);
455 
456     if (s->crossfade_is_over) {
457         ret = ff_inlink_consume_frame(ctx->inputs[1], &in);
458         if (ret > 0) {
459             in->pts = s->pts;
460             s->pts += av_rescale_q(in->nb_samples,
461                       (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
462             return ff_filter_frame(outlink, in);
463         } else if (ret < 0) {
464             return ret;
465         } else if (ff_inlink_acknowledge_status(ctx->inputs[1], &status, &pts)) {
466             ff_outlink_set_status(ctx->outputs[0], status, pts);
467             return 0;
468         } else if (!ret) {
469             if (ff_outlink_frame_wanted(ctx->outputs[0])) {
470                 ff_inlink_request_frame(ctx->inputs[1]);
471                 return 0;
472             }
473         }
474     }
475 
476     nb_samples = ff_inlink_queued_samples(ctx->inputs[0]);
477     if (nb_samples  > s->nb_samples) {
478         nb_samples -= s->nb_samples;
479         ret = ff_inlink_consume_samples(ctx->inputs[0], nb_samples, nb_samples, &in);
480         if (ret < 0)
481             return ret;
482         in->pts = s->pts;
483         s->pts += av_rescale_q(in->nb_samples,
484             (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
485         return ff_filter_frame(outlink, in);
486     } else if (s->cf0_eof && nb_samples >= s->nb_samples &&
487                ff_inlink_queued_samples(ctx->inputs[1]) >= s->nb_samples) {
488         if (s->overlap) {
489             out = ff_get_audio_buffer(outlink, s->nb_samples);
490             if (!out)
491                 return AVERROR(ENOMEM);
492 
493             ret = ff_inlink_consume_samples(ctx->inputs[0], s->nb_samples, s->nb_samples, &cf[0]);
494             if (ret < 0) {
495                 av_frame_free(&out);
496                 return ret;
497             }
498 
499             ret = ff_inlink_consume_samples(ctx->inputs[1], s->nb_samples, s->nb_samples, &cf[1]);
500             if (ret < 0) {
501                 av_frame_free(&out);
502                 return ret;
503             }
504 
505             s->crossfade_samples(out->extended_data, cf[0]->extended_data,
506                                  cf[1]->extended_data,
507                                  s->nb_samples, out->ch_layout.nb_channels,
508                                  s->curve, s->curve2);
509             out->pts = s->pts;
510             s->pts += av_rescale_q(s->nb_samples,
511                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
512             s->crossfade_is_over = 1;
513             av_frame_free(&cf[0]);
514             av_frame_free(&cf[1]);
515             return ff_filter_frame(outlink, out);
516         } else {
517             out = ff_get_audio_buffer(outlink, s->nb_samples);
518             if (!out)
519                 return AVERROR(ENOMEM);
520 
521             ret = ff_inlink_consume_samples(ctx->inputs[0], s->nb_samples, s->nb_samples, &cf[0]);
522             if (ret < 0) {
523                 av_frame_free(&out);
524                 return ret;
525             }
526 
527             s->fade_samples(out->extended_data, cf[0]->extended_data, s->nb_samples,
528                             outlink->ch_layout.nb_channels, -1, s->nb_samples - 1, s->nb_samples, s->curve);
529             out->pts = s->pts;
530             s->pts += av_rescale_q(s->nb_samples,
531                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
532             av_frame_free(&cf[0]);
533             ret = ff_filter_frame(outlink, out);
534             if (ret < 0)
535                 return ret;
536 
537             out = ff_get_audio_buffer(outlink, s->nb_samples);
538             if (!out)
539                 return AVERROR(ENOMEM);
540 
541             ret = ff_inlink_consume_samples(ctx->inputs[1], s->nb_samples, s->nb_samples, &cf[1]);
542             if (ret < 0) {
543                 av_frame_free(&out);
544                 return ret;
545             }
546 
547             s->fade_samples(out->extended_data, cf[1]->extended_data, s->nb_samples,
548                             outlink->ch_layout.nb_channels, 1, 0, s->nb_samples, s->curve2);
549             out->pts = s->pts;
550             s->pts += av_rescale_q(s->nb_samples,
551                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
552             s->crossfade_is_over = 1;
553             av_frame_free(&cf[1]);
554             return ff_filter_frame(outlink, out);
555         }
556     } else if (ff_outlink_frame_wanted(ctx->outputs[0])) {
557         if (!s->cf0_eof && ff_outlink_get_status(ctx->inputs[0])) {
558             s->cf0_eof = 1;
559         }
560         if (ff_outlink_get_status(ctx->inputs[1])) {
561             ff_outlink_set_status(ctx->outputs[0], AVERROR_EOF, AV_NOPTS_VALUE);
562             return 0;
563         }
564         if (!s->cf0_eof)
565             ff_inlink_request_frame(ctx->inputs[0]);
566         else
567             ff_inlink_request_frame(ctx->inputs[1]);
568         return 0;
569     }
570 
571     return ret;
572 }
573 
acrossfade_config_output(AVFilterLink * outlink)574 static int acrossfade_config_output(AVFilterLink *outlink)
575 {
576     AVFilterContext *ctx = outlink->src;
577     AudioFadeContext *s  = ctx->priv;
578 
579     outlink->time_base   = ctx->inputs[0]->time_base;
580 
581     switch (outlink->format) {
582     case AV_SAMPLE_FMT_DBL:  s->crossfade_samples = crossfade_samples_dbl;  break;
583     case AV_SAMPLE_FMT_DBLP: s->crossfade_samples = crossfade_samples_dblp; break;
584     case AV_SAMPLE_FMT_FLT:  s->crossfade_samples = crossfade_samples_flt;  break;
585     case AV_SAMPLE_FMT_FLTP: s->crossfade_samples = crossfade_samples_fltp; break;
586     case AV_SAMPLE_FMT_S16:  s->crossfade_samples = crossfade_samples_s16;  break;
587     case AV_SAMPLE_FMT_S16P: s->crossfade_samples = crossfade_samples_s16p; break;
588     case AV_SAMPLE_FMT_S32:  s->crossfade_samples = crossfade_samples_s32;  break;
589     case AV_SAMPLE_FMT_S32P: s->crossfade_samples = crossfade_samples_s32p; break;
590     }
591 
592     config_output(outlink);
593 
594     return 0;
595 }
596 
597 static const AVFilterPad avfilter_af_acrossfade_inputs[] = {
598     {
599         .name         = "crossfade0",
600         .type         = AVMEDIA_TYPE_AUDIO,
601     },
602     {
603         .name         = "crossfade1",
604         .type         = AVMEDIA_TYPE_AUDIO,
605     },
606 };
607 
608 static const AVFilterPad avfilter_af_acrossfade_outputs[] = {
609     {
610         .name          = "default",
611         .type          = AVMEDIA_TYPE_AUDIO,
612         .config_props  = acrossfade_config_output,
613     },
614 };
615 
616 const AVFilter ff_af_acrossfade = {
617     .name          = "acrossfade",
618     .description   = NULL_IF_CONFIG_SMALL("Cross fade two input audio streams."),
619     .priv_size     = sizeof(AudioFadeContext),
620     .activate      = activate,
621     .priv_class    = &acrossfade_class,
622     FILTER_INPUTS(avfilter_af_acrossfade_inputs),
623     FILTER_OUTPUTS(avfilter_af_acrossfade_outputs),
624     FILTER_SAMPLEFMTS_ARRAY(sample_fmts),
625 };
626 
627 #endif /* CONFIG_ACROSSFADE_FILTER */
628