libavfilter/af_afade.c
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 /*
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  * Copyright (c) 2013-2015 Paul B Mahol
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  *
  * This file is part of FFmpeg.
  *
  * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
  * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
  * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
 /**
  * @file
  * fade audio filter
  */
 
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 #include "libavutil/audio_fifo.h"
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 #include "libavutil/opt.h"
 #include "audio.h"
 #include "avfilter.h"
 #include "internal.h"
 
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 typedef struct AudioFadeContext {
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     const AVClass *class;
     int type;
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     int curve, curve2;
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     int64_t nb_samples;
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     int64_t start_sample;
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     int64_t duration;
     int64_t start_time;
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     int overlap;
     int cf0_eof;
     int crossfade_is_over;
     AVAudioFifo *fifo[2];
     int64_t pts;
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     void (*fade_samples)(uint8_t **dst, uint8_t * const *src,
                          int nb_samples, int channels, int direction,
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                          int64_t start, int64_t range, int curve);
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     void (*crossfade_samples)(uint8_t **dst, uint8_t * const *cf0,
                               uint8_t * const *cf1,
                               int nb_samples, int channels,
                               int curve0, int curve1);
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 } AudioFadeContext;
 
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 enum CurveType { TRI, QSIN, ESIN, HSIN, LOG, IPAR, QUA, CUB, SQU, CBR, PAR, EXP, IQSIN, IHSIN, DESE, DESI, NB_CURVES };
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 #define OFFSET(x) offsetof(AudioFadeContext, x)
 #define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM
 
 static int query_formats(AVFilterContext *ctx)
 {
     AVFilterFormats *formats;
     AVFilterChannelLayouts *layouts;
     static const enum AVSampleFormat sample_fmts[] = {
         AV_SAMPLE_FMT_S16, AV_SAMPLE_FMT_S16P,
         AV_SAMPLE_FMT_S32, AV_SAMPLE_FMT_S32P,
         AV_SAMPLE_FMT_FLT, AV_SAMPLE_FMT_FLTP,
         AV_SAMPLE_FMT_DBL, AV_SAMPLE_FMT_DBLP,
         AV_SAMPLE_FMT_NONE
     };
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     int ret;
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     layouts = ff_all_channel_counts();
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     if (!layouts)
         return AVERROR(ENOMEM);
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     ret = ff_set_common_channel_layouts(ctx, layouts);
     if (ret < 0)
         return ret;
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     formats = ff_make_format_list(sample_fmts);
     if (!formats)
         return AVERROR(ENOMEM);
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     ret = ff_set_common_formats(ctx, formats);
     if (ret < 0)
         return ret;
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     formats = ff_all_samplerates();
     if (!formats)
         return AVERROR(ENOMEM);
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     return ff_set_common_samplerates(ctx, formats);
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 }
 
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 static double fade_gain(int curve, int64_t index, int64_t range)
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 {
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 #define CUBE(a) ((a)*(a)*(a))
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     double gain;
 
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     gain = av_clipd(1.0 * index / range, 0, 1.0);
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     switch (curve) {
     case QSIN:
         gain = sin(gain * M_PI / 2.0);
         break;
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     case IQSIN:
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         /* 0.6... = 2 / M_PI */
         gain = 0.6366197723675814 * asin(gain);
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         break;
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     case ESIN:
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         gain = 1.0 - cos(M_PI / 4.0 * (CUBE(2.0*gain - 1) + 1));
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         break;
     case HSIN:
         gain = (1.0 - cos(gain * M_PI)) / 2.0;
         break;
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     case IHSIN:
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         /* 0.3... = 1 / M_PI */
         gain = 0.3183098861837907 * acos(1 - 2 * gain);
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         break;
     case EXP:
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         /* -11.5... = 5*ln(0.1) */
         gain = exp(-11.512925464970227 * (1 - gain));
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         break;
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     case LOG:
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         gain = av_clipd(1 + 0.2 * log10(gain), 0, 1.0);
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         break;
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     case PAR:
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         gain = 1 - sqrt(1 - gain);
         break;
     case IPAR:
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         gain = (1 - (1 - gain) * (1 - gain));
         break;
     case QUA:
         gain *= gain;
         break;
     case CUB:
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         gain = CUBE(gain);
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         break;
     case SQU:
         gain = sqrt(gain);
         break;
     case CBR:
         gain = cbrt(gain);
         break;
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     case DESE:
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         gain = gain <= 0.5 ? cbrt(2 * gain) / 2: 1 - cbrt(2 * (1 - gain)) / 2;
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         break;
     case DESI:
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         gain = gain <= 0.5 ? CUBE(2 * gain) / 2: 1 - CUBE(2 * (1 - gain)) / 2;
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         break;
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     }
 
     return gain;
 }
 
 #define FADE_PLANAR(name, type)                                             \
 static void fade_samples_## name ##p(uint8_t **dst, uint8_t * const *src,   \
                                      int nb_samples, int channels, int dir, \
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                                      int64_t start, int64_t range, int curve) \
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 {                                                                           \
     int i, c;                                                               \
                                                                             \
     for (i = 0; i < nb_samples; i++) {                                      \
         double gain = fade_gain(curve, start + i * dir, range);             \
         for (c = 0; c < channels; c++) {                                    \
             type *d = (type *)dst[c];                                       \
             const type *s = (type *)src[c];                                 \
                                                                             \
             d[i] = s[i] * gain;                                             \
         }                                                                   \
     }                                                                       \
 }
 
 #define FADE(name, type)                                                    \
 static void fade_samples_## name (uint8_t **dst, uint8_t * const *src,      \
                                   int nb_samples, int channels, int dir,    \
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                                   int64_t start, int64_t range, int curve)  \
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 {                                                                           \
     type *d = (type *)dst[0];                                               \
     const type *s = (type *)src[0];                                         \
     int i, c, k = 0;                                                        \
                                                                             \
     for (i = 0; i < nb_samples; i++) {                                      \
         double gain = fade_gain(curve, start + i * dir, range);             \
         for (c = 0; c < channels; c++, k++)                                 \
             d[k] = s[k] * gain;                                             \
     }                                                                       \
 }
 
 FADE_PLANAR(dbl, double)
 FADE_PLANAR(flt, float)
 FADE_PLANAR(s16, int16_t)
 FADE_PLANAR(s32, int32_t)
 
 FADE(dbl, double)
 FADE(flt, float)
 FADE(s16, int16_t)
 FADE(s32, int32_t)
 
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 static int config_output(AVFilterLink *outlink)
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 {
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     AVFilterContext *ctx = outlink->src;
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     AudioFadeContext *s  = ctx->priv;
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     switch (outlink->format) {
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     case AV_SAMPLE_FMT_DBL:  s->fade_samples = fade_samples_dbl;  break;
     case AV_SAMPLE_FMT_DBLP: s->fade_samples = fade_samples_dblp; break;
     case AV_SAMPLE_FMT_FLT:  s->fade_samples = fade_samples_flt;  break;
     case AV_SAMPLE_FMT_FLTP: s->fade_samples = fade_samples_fltp; break;
     case AV_SAMPLE_FMT_S16:  s->fade_samples = fade_samples_s16;  break;
     case AV_SAMPLE_FMT_S16P: s->fade_samples = fade_samples_s16p; break;
     case AV_SAMPLE_FMT_S32:  s->fade_samples = fade_samples_s32;  break;
     case AV_SAMPLE_FMT_S32P: s->fade_samples = fade_samples_s32p; break;
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     }
 
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     if (s->duration)
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         s->nb_samples = av_rescale(s->duration, outlink->sample_rate, AV_TIME_BASE);
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     if (s->start_time)
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         s->start_sample = av_rescale(s->start_time, outlink->sample_rate, AV_TIME_BASE);
 
     return 0;
 }
 
 #if CONFIG_AFADE_FILTER
 
 static const AVOption afade_options[] = {
     { "type",         "set the fade direction",                      OFFSET(type),         AV_OPT_TYPE_INT,    {.i64 = 0    }, 0, 1, FLAGS, "type" },
     { "t",            "set the fade direction",                      OFFSET(type),         AV_OPT_TYPE_INT,    {.i64 = 0    }, 0, 1, FLAGS, "type" },
     { "in",           "fade-in",                                     0,                    AV_OPT_TYPE_CONST,  {.i64 = 0    }, 0, 0, FLAGS, "type" },
     { "out",          "fade-out",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = 1    }, 0, 0, FLAGS, "type" },
     { "start_sample", "set number of first sample to start fading",  OFFSET(start_sample), AV_OPT_TYPE_INT64,  {.i64 = 0    }, 0, INT64_MAX, FLAGS },
     { "ss",           "set number of first sample to start fading",  OFFSET(start_sample), AV_OPT_TYPE_INT64,  {.i64 = 0    }, 0, INT64_MAX, FLAGS },
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     { "nb_samples",   "set number of samples for fade duration",     OFFSET(nb_samples),   AV_OPT_TYPE_INT64,  {.i64 = 44100}, 1, INT64_MAX, FLAGS },
     { "ns",           "set number of samples for fade duration",     OFFSET(nb_samples),   AV_OPT_TYPE_INT64,  {.i64 = 44100}, 1, INT64_MAX, FLAGS },
     { "start_time",   "set time to start fading",                    OFFSET(start_time),   AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT64_MAX, FLAGS },
     { "st",           "set time to start fading",                    OFFSET(start_time),   AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT64_MAX, FLAGS },
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     { "duration",     "set fade duration",                           OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },
     { "d",            "set fade duration",                           OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, INT32_MAX, FLAGS },
     { "curve",        "set fade curve type",                         OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
     { "c",            "set fade curve type",                         OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
     { "tri",          "linear slope",                                0,                    AV_OPT_TYPE_CONST,  {.i64 = TRI  }, 0, 0, FLAGS, "curve" },
     { "qsin",         "quarter of sine wave",                        0,                    AV_OPT_TYPE_CONST,  {.i64 = QSIN }, 0, 0, FLAGS, "curve" },
     { "esin",         "exponential sine wave",                       0,                    AV_OPT_TYPE_CONST,  {.i64 = ESIN }, 0, 0, FLAGS, "curve" },
     { "hsin",         "half of sine wave",                           0,                    AV_OPT_TYPE_CONST,  {.i64 = HSIN }, 0, 0, FLAGS, "curve" },
     { "log",          "logarithmic",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = LOG  }, 0, 0, FLAGS, "curve" },
     { "ipar",         "inverted parabola",                           0,                    AV_OPT_TYPE_CONST,  {.i64 = IPAR }, 0, 0, FLAGS, "curve" },
     { "qua",          "quadratic",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = QUA  }, 0, 0, FLAGS, "curve" },
     { "cub",          "cubic",                                       0,                    AV_OPT_TYPE_CONST,  {.i64 = CUB  }, 0, 0, FLAGS, "curve" },
     { "squ",          "square root",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = SQU  }, 0, 0, FLAGS, "curve" },
     { "cbr",          "cubic root",                                  0,                    AV_OPT_TYPE_CONST,  {.i64 = CBR  }, 0, 0, FLAGS, "curve" },
     { "par",          "parabola",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = PAR  }, 0, 0, FLAGS, "curve" },
     { "exp",          "exponential",                                 0,                    AV_OPT_TYPE_CONST,  {.i64 = EXP  }, 0, 0, FLAGS, "curve" },
     { "iqsin",        "inverted quarter of sine wave",               0,                    AV_OPT_TYPE_CONST,  {.i64 = IQSIN}, 0, 0, FLAGS, "curve" },
     { "ihsin",        "inverted half of sine wave",                  0,                    AV_OPT_TYPE_CONST,  {.i64 = IHSIN}, 0, 0, FLAGS, "curve" },
     { "dese",         "double-exponential seat",                     0,                    AV_OPT_TYPE_CONST,  {.i64 = DESE }, 0, 0, FLAGS, "curve" },
     { "desi",         "double-exponential sigmoid",                  0,                    AV_OPT_TYPE_CONST,  {.i64 = DESI }, 0, 0, FLAGS, "curve" },
     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(afade);
 
 static av_cold int init(AVFilterContext *ctx)
 {
     AudioFadeContext *s = ctx->priv;
 
     if (INT64_MAX - s->nb_samples < s->start_sample)
         return AVERROR(EINVAL);
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     return 0;
 }
 
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 static int filter_frame(AVFilterLink *inlink, AVFrame *buf)
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 {
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     AudioFadeContext *s     = inlink->dst->priv;
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     AVFilterLink *outlink   = inlink->dst->outputs[0];
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     int nb_samples          = buf->nb_samples;
     AVFrame *out_buf;
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     int64_t cur_sample = av_rescale_q(buf->pts, inlink->time_base, (AVRational){1, inlink->sample_rate});
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     if ((!s->type && (s->start_sample + s->nb_samples < cur_sample)) ||
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         ( s->type && (cur_sample + nb_samples < s->start_sample)))
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         return ff_filter_frame(outlink, buf);
 
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     if (av_frame_is_writable(buf)) {
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         out_buf = buf;
     } else {
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         out_buf = ff_get_audio_buffer(inlink, nb_samples);
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         if (!out_buf)
             return AVERROR(ENOMEM);
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         av_frame_copy_props(out_buf, buf);
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     }
 
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     if ((!s->type && (cur_sample + nb_samples < s->start_sample)) ||
         ( s->type && (s->start_sample + s->nb_samples < cur_sample))) {
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         av_samples_set_silence(out_buf->extended_data, 0, nb_samples,
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                                out_buf->channels, out_buf->format);
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     } else {
         int64_t start;
 
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         if (!s->type)
             start = cur_sample - s->start_sample;
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         else
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             start = s->start_sample + s->nb_samples - cur_sample;
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         s->fade_samples(out_buf->extended_data, buf->extended_data,
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                         nb_samples, buf->channels,
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                         s->type ? -1 : 1, start,
                         s->nb_samples, s->curve);
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     }
 
     if (buf != out_buf)
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         av_frame_free(&buf);
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     return ff_filter_frame(outlink, out_buf);
 }
 
 static const AVFilterPad avfilter_af_afade_inputs[] = {
     {
         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_af_afade_outputs[] = {
     {
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         .name         = "default",
         .type         = AVMEDIA_TYPE_AUDIO,
         .config_props = config_output,
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     },
     { NULL }
 };
 
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 AVFilter ff_af_afade = {
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     .name          = "afade",
     .description   = NULL_IF_CONFIG_SMALL("Fade in/out input audio."),
     .query_formats = query_formats,
     .priv_size     = sizeof(AudioFadeContext),
     .init          = init,
     .inputs        = avfilter_af_afade_inputs,
     .outputs       = avfilter_af_afade_outputs,
     .priv_class    = &afade_class,
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     .flags         = AVFILTER_FLAG_SUPPORT_TIMELINE_GENERIC,
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 };
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 #endif /* CONFIG_AFADE_FILTER */
 
 #if CONFIG_ACROSSFADE_FILTER
 
 static const AVOption acrossfade_options[] = {
     { "nb_samples",   "set number of samples for cross fade duration", OFFSET(nb_samples),   AV_OPT_TYPE_INT,    {.i64 = 44100}, 1, INT32_MAX/10, FLAGS },
     { "ns",           "set number of samples for cross fade duration", OFFSET(nb_samples),   AV_OPT_TYPE_INT,    {.i64 = 44100}, 1, INT32_MAX/10, FLAGS },
     { "duration",     "set cross fade duration",                       OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, 60, FLAGS },
     { "d",            "set cross fade duration",                       OFFSET(duration),     AV_OPT_TYPE_DURATION, {.i64 = 0. }, 0, 60, FLAGS },
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     { "overlap",      "overlap 1st stream end with 2nd stream start",  OFFSET(overlap),      AV_OPT_TYPE_BOOL,   {.i64 = 1    }, 0,  1, FLAGS },
     { "o",            "overlap 1st stream end with 2nd stream start",  OFFSET(overlap),      AV_OPT_TYPE_BOOL,   {.i64 = 1    }, 0,  1, FLAGS },
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     { "curve1",       "set fade curve type for 1st stream",            OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
     { "c1",           "set fade curve type for 1st stream",            OFFSET(curve),        AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
     {     "tri",      "linear slope",                                  0,                    AV_OPT_TYPE_CONST,  {.i64 = TRI  }, 0, 0, FLAGS, "curve" },
     {     "qsin",     "quarter of sine wave",                          0,                    AV_OPT_TYPE_CONST,  {.i64 = QSIN }, 0, 0, FLAGS, "curve" },
     {     "esin",     "exponential sine wave",                         0,                    AV_OPT_TYPE_CONST,  {.i64 = ESIN }, 0, 0, FLAGS, "curve" },
     {     "hsin",     "half of sine wave",                             0,                    AV_OPT_TYPE_CONST,  {.i64 = HSIN }, 0, 0, FLAGS, "curve" },
     {     "log",      "logarithmic",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = LOG  }, 0, 0, FLAGS, "curve" },
     {     "ipar",     "inverted parabola",                             0,                    AV_OPT_TYPE_CONST,  {.i64 = IPAR }, 0, 0, FLAGS, "curve" },
     {     "qua",      "quadratic",                                     0,                    AV_OPT_TYPE_CONST,  {.i64 = QUA  }, 0, 0, FLAGS, "curve" },
     {     "cub",      "cubic",                                         0,                    AV_OPT_TYPE_CONST,  {.i64 = CUB  }, 0, 0, FLAGS, "curve" },
     {     "squ",      "square root",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = SQU  }, 0, 0, FLAGS, "curve" },
     {     "cbr",      "cubic root",                                    0,                    AV_OPT_TYPE_CONST,  {.i64 = CBR  }, 0, 0, FLAGS, "curve" },
     {     "par",      "parabola",                                      0,                    AV_OPT_TYPE_CONST,  {.i64 = PAR  }, 0, 0, FLAGS, "curve" },
     {     "exp",      "exponential",                                   0,                    AV_OPT_TYPE_CONST,  {.i64 = EXP  }, 0, 0, FLAGS, "curve" },
     {     "iqsin",    "inverted quarter of sine wave",                 0,                    AV_OPT_TYPE_CONST,  {.i64 = IQSIN}, 0, 0, FLAGS, "curve" },
     {     "ihsin",    "inverted half of sine wave",                    0,                    AV_OPT_TYPE_CONST,  {.i64 = IHSIN}, 0, 0, FLAGS, "curve" },
     {     "dese",     "double-exponential seat",                       0,                    AV_OPT_TYPE_CONST,  {.i64 = DESE }, 0, 0, FLAGS, "curve" },
     {     "desi",     "double-exponential sigmoid",                    0,                    AV_OPT_TYPE_CONST,  {.i64 = DESI }, 0, 0, FLAGS, "curve" },
     { "curve2",       "set fade curve type for 2nd stream",            OFFSET(curve2),       AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
     { "c2",           "set fade curve type for 2nd stream",            OFFSET(curve2),       AV_OPT_TYPE_INT,    {.i64 = TRI  }, 0, NB_CURVES - 1, FLAGS, "curve" },
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     { NULL }
 };
 
 AVFILTER_DEFINE_CLASS(acrossfade);
 
 #define CROSSFADE_PLANAR(name, type)                                           \
 static void crossfade_samples_## name ##p(uint8_t **dst, uint8_t * const *cf0, \
                                           uint8_t * const *cf1,                \
                                           int nb_samples, int channels,        \
                                           int curve0, int curve1)              \
 {                                                                              \
     int i, c;                                                                  \
                                                                                \
     for (i = 0; i < nb_samples; i++) {                                         \
         double gain0 = fade_gain(curve0, nb_samples - 1 - i, nb_samples);      \
         double gain1 = fade_gain(curve1, i, nb_samples);                       \
         for (c = 0; c < channels; c++) {                                       \
             type *d = (type *)dst[c];                                          \
             const type *s0 = (type *)cf0[c];                                   \
             const type *s1 = (type *)cf1[c];                                   \
                                                                                \
             d[i] = s0[i] * gain0 + s1[i] * gain1;                              \
         }                                                                      \
     }                                                                          \
 }
 
 #define CROSSFADE(name, type)                                               \
 static void crossfade_samples_## name (uint8_t **dst, uint8_t * const *cf0, \
                                        uint8_t * const *cf1,                \
                                        int nb_samples, int channels,        \
                                        int curve0, int curve1)              \
 {                                                                           \
     type *d = (type *)dst[0];                                               \
     const type *s0 = (type *)cf0[0];                                        \
     const type *s1 = (type *)cf1[0];                                        \
     int i, c, k = 0;                                                        \
                                                                             \
     for (i = 0; i < nb_samples; i++) {                                      \
         double gain0 = fade_gain(curve0, nb_samples - 1 - i, nb_samples);   \
         double gain1 = fade_gain(curve1, i, nb_samples);                    \
         for (c = 0; c < channels; c++, k++)                                 \
             d[k] = s0[k] * gain0 + s1[k] * gain1;                           \
     }                                                                       \
 }
 
 CROSSFADE_PLANAR(dbl, double)
 CROSSFADE_PLANAR(flt, float)
 CROSSFADE_PLANAR(s16, int16_t)
 CROSSFADE_PLANAR(s32, int32_t)
 
 CROSSFADE(dbl, double)
 CROSSFADE(flt, float)
 CROSSFADE(s16, int16_t)
 CROSSFADE(s32, int32_t)
 
 static int acrossfade_filter_frame(AVFilterLink *inlink, AVFrame *in)
 {
     AVFilterContext *ctx  = inlink->dst;
     AudioFadeContext *s   = ctx->priv;
     AVFilterLink *outlink = ctx->outputs[0];
     AVFrame *out, *cf[2] = { NULL };
     int ret = 0, nb_samples;
 
     if (s->crossfade_is_over) {
         in->pts = s->pts;
         s->pts += av_rescale_q(in->nb_samples,
             (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
         return ff_filter_frame(outlink, in);
     } else if (inlink == ctx->inputs[0]) {
         av_audio_fifo_write(s->fifo[0], (void **)in->extended_data, in->nb_samples);
 
         nb_samples = av_audio_fifo_size(s->fifo[0]) - s->nb_samples;
         if (nb_samples > 0) {
             out = ff_get_audio_buffer(outlink, nb_samples);
             if (!out) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
             av_audio_fifo_read(s->fifo[0], (void **)out->extended_data, nb_samples);
             out->pts = s->pts;
             s->pts += av_rescale_q(nb_samples,
                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
             ret = ff_filter_frame(outlink, out);
         }
     } else if (av_audio_fifo_size(s->fifo[1]) < s->nb_samples) {
         if (!s->overlap && av_audio_fifo_size(s->fifo[0]) > 0) {
             nb_samples = av_audio_fifo_size(s->fifo[0]);
 
             cf[0] = ff_get_audio_buffer(outlink, nb_samples);
             out = ff_get_audio_buffer(outlink, nb_samples);
             if (!out || !cf[0]) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
             av_audio_fifo_read(s->fifo[0], (void **)cf[0]->extended_data, nb_samples);
 
             s->fade_samples(out->extended_data, cf[0]->extended_data, nb_samples,
                             outlink->channels, -1, nb_samples - 1, nb_samples, s->curve);
             out->pts = s->pts;
             s->pts += av_rescale_q(nb_samples,
                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
             ret = ff_filter_frame(outlink, out);
             if (ret < 0)
                 goto fail;
         }
 
         av_audio_fifo_write(s->fifo[1], (void **)in->extended_data, in->nb_samples);
     } else if (av_audio_fifo_size(s->fifo[1]) >= s->nb_samples) {
04a7ce1a
         av_audio_fifo_write(s->fifo[1], (void **)in->extended_data, in->nb_samples);
 
4a2836ea
         if (s->overlap) {
             cf[0] = ff_get_audio_buffer(outlink, s->nb_samples);
             cf[1] = ff_get_audio_buffer(outlink, s->nb_samples);
             out = ff_get_audio_buffer(outlink, s->nb_samples);
             if (!out || !cf[0] || !cf[1]) {
                 av_frame_free(&out);
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
 
             av_audio_fifo_read(s->fifo[0], (void **)cf[0]->extended_data, s->nb_samples);
             av_audio_fifo_read(s->fifo[1], (void **)cf[1]->extended_data, s->nb_samples);
 
             s->crossfade_samples(out->extended_data, cf[0]->extended_data,
                                  cf[1]->extended_data,
6af050d7
                                  s->nb_samples, in->channels,
4a2836ea
                                  s->curve, s->curve2);
             out->pts = s->pts;
             s->pts += av_rescale_q(s->nb_samples,
                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
             ret = ff_filter_frame(outlink, out);
             if (ret < 0)
                 goto fail;
         } else {
             out = ff_get_audio_buffer(outlink, s->nb_samples);
             cf[1] = ff_get_audio_buffer(outlink, s->nb_samples);
             if (!out || !cf[1]) {
                 ret = AVERROR(ENOMEM);
                 av_frame_free(&out);
                 goto fail;
             }
 
             av_audio_fifo_read(s->fifo[1], (void **)cf[1]->extended_data, s->nb_samples);
 
             s->fade_samples(out->extended_data, cf[1]->extended_data, s->nb_samples,
                             outlink->channels, 1, 0, s->nb_samples, s->curve2);
             out->pts = s->pts;
             s->pts += av_rescale_q(s->nb_samples,
                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
             ret = ff_filter_frame(outlink, out);
             if (ret < 0)
                 goto fail;
         }
 
         nb_samples = av_audio_fifo_size(s->fifo[1]);
         if (nb_samples > 0) {
             out = ff_get_audio_buffer(outlink, nb_samples);
             if (!out) {
                 ret = AVERROR(ENOMEM);
                 goto fail;
             }
 
             av_audio_fifo_read(s->fifo[1], (void **)out->extended_data, nb_samples);
             out->pts = s->pts;
             s->pts += av_rescale_q(nb_samples,
                 (AVRational){ 1, outlink->sample_rate }, outlink->time_base);
             ret = ff_filter_frame(outlink, out);
         }
         s->crossfade_is_over = 1;
     }
 
 fail:
     av_frame_free(&in);
     av_frame_free(&cf[0]);
     av_frame_free(&cf[1]);
     return ret;
 }
 
 static int acrossfade_request_frame(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AudioFadeContext *s = ctx->priv;
     int ret = 0;
 
     if (!s->cf0_eof) {
         AVFilterLink *cf0 = ctx->inputs[0];
         ret = ff_request_frame(cf0);
         if (ret < 0 && ret != AVERROR_EOF)
             return ret;
         if (ret == AVERROR_EOF) {
             s->cf0_eof = 1;
             ret = 0;
         }
     } else {
         AVFilterLink *cf1 = ctx->inputs[1];
         int nb_samples = av_audio_fifo_size(s->fifo[1]);
 
         ret = ff_request_frame(cf1);
         if (ret == AVERROR_EOF && nb_samples > 0) {
             AVFrame *out = ff_get_audio_buffer(outlink, nb_samples);
             if (!out)
                 return AVERROR(ENOMEM);
 
             av_audio_fifo_read(s->fifo[1], (void **)out->extended_data, nb_samples);
             ret = ff_filter_frame(outlink, out);
         }
     }
 
     return ret;
 }
 
 static int acrossfade_config_output(AVFilterLink *outlink)
 {
     AVFilterContext *ctx = outlink->src;
     AudioFadeContext *s  = ctx->priv;
 
     if (ctx->inputs[0]->sample_rate != ctx->inputs[1]->sample_rate) {
         av_log(ctx, AV_LOG_ERROR,
                "Inputs must have the same sample rate "
                "%d for in0 vs %d for in1\n",
                ctx->inputs[0]->sample_rate, ctx->inputs[1]->sample_rate);
         return AVERROR(EINVAL);
     }
 
     outlink->sample_rate = ctx->inputs[0]->sample_rate;
     outlink->time_base   = ctx->inputs[0]->time_base;
     outlink->channel_layout = ctx->inputs[0]->channel_layout;
     outlink->channels = ctx->inputs[0]->channels;
 
     switch (outlink->format) {
     case AV_SAMPLE_FMT_DBL:  s->crossfade_samples = crossfade_samples_dbl;  break;
     case AV_SAMPLE_FMT_DBLP: s->crossfade_samples = crossfade_samples_dblp; break;
     case AV_SAMPLE_FMT_FLT:  s->crossfade_samples = crossfade_samples_flt;  break;
     case AV_SAMPLE_FMT_FLTP: s->crossfade_samples = crossfade_samples_fltp; break;
     case AV_SAMPLE_FMT_S16:  s->crossfade_samples = crossfade_samples_s16;  break;
     case AV_SAMPLE_FMT_S16P: s->crossfade_samples = crossfade_samples_s16p; break;
     case AV_SAMPLE_FMT_S32:  s->crossfade_samples = crossfade_samples_s32;  break;
     case AV_SAMPLE_FMT_S32P: s->crossfade_samples = crossfade_samples_s32p; break;
     }
 
     config_output(outlink);
 
     s->fifo[0] = av_audio_fifo_alloc(outlink->format, outlink->channels, s->nb_samples);
     s->fifo[1] = av_audio_fifo_alloc(outlink->format, outlink->channels, s->nb_samples);
     if (!s->fifo[0] || !s->fifo[1])
         return AVERROR(ENOMEM);
 
     return 0;
 }
 
 static av_cold void uninit(AVFilterContext *ctx)
 {
     AudioFadeContext *s = ctx->priv;
 
     av_audio_fifo_free(s->fifo[0]);
     av_audio_fifo_free(s->fifo[1]);
 }
 
 static const AVFilterPad avfilter_af_acrossfade_inputs[] = {
     {
         .name         = "crossfade0",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = acrossfade_filter_frame,
     },
     {
         .name         = "crossfade1",
         .type         = AVMEDIA_TYPE_AUDIO,
         .filter_frame = acrossfade_filter_frame,
     },
     { NULL }
 };
 
 static const AVFilterPad avfilter_af_acrossfade_outputs[] = {
     {
         .name          = "default",
         .type          = AVMEDIA_TYPE_AUDIO,
         .request_frame = acrossfade_request_frame,
         .config_props  = acrossfade_config_output,
     },
     { NULL }
 };
 
 AVFilter ff_af_acrossfade = {
     .name          = "acrossfade",
     .description   = NULL_IF_CONFIG_SMALL("Cross fade two input audio streams."),
     .query_formats = query_formats,
     .priv_size     = sizeof(AudioFadeContext),
     .uninit        = uninit,
     .priv_class    = &acrossfade_class,
     .inputs        = avfilter_af_acrossfade_inputs,
     .outputs       = avfilter_af_acrossfade_outputs,
 };
 
 #endif /* CONFIG_ACROSSFADE_FILTER */