audio - ffmpeg中不同的淡入/淡出曲线有什么区别？

Question

这是 afade 的可能曲线列表和 acrossfade从这里过滤https://ffmpeg.org/ffmpeg-filters.html#afade-1

tri
    select triangular, linear slope (default) 

qsin
    select quarter of sine wave 

hsin
    select half of sine wave 

esin
    select exponential sine wave 

log
    select logarithmic 

ipar
    select inverted parabola 

qua
    select quadratic 

cub
    select cubic 

squ
    select square root 

cbr
    select cubic root 

par
    select parabola 

exp
    select exponential 

iqsin
    select inverted quarter of sine wave 

ihsin
    select inverted half of sine wave 

dese
    select double-exponential seat 

desi
    select double-exponential sigmoid 

这是他们的代码，来自 libavfilter/af_afade.c :

switch (curve) {
case QSIN:
    gain = sin(gain * M_PI / 2.0);
    break;
case IQSIN:
    /* 0.6... = 2 / M_PI */
    gain = 0.6366197723675814 * asin(gain);
    break;
case ESIN:
    gain = 1.0 - cos(M_PI / 4.0 * (CUBE(2.0*gain - 1) + 1));
    break;
case HSIN:
    gain = (1.0 - cos(gain * M_PI)) / 2.0;
    break;
case IHSIN:
    /* 0.3... = 1 / M_PI */
    gain = 0.3183098861837907 * acos(1 - 2 * gain);
    break;
case EXP:
    /* -11.5... = 5*ln(0.1) */
    gain = exp(-11.512925464970227 * (1 - gain));
    break;
case LOG:
    gain = av_clipd(1 + 0.2 * log10(gain), 0, 1.0);
    break;
case PAR:
    gain = 1 - sqrt(1 - gain);
    break;
case IPAR:
    gain = (1 - (1 - gain) * (1 - gain));
    break;
case QUA:
    gain *= gain;
    break;
case CUB:
    gain = CUBE(gain);
    break;
case SQU:
    gain = sqrt(gain);
    break;
case CBR:
    gain = cbrt(gain);
    break;
case DESE:
    gain = gain <= 0.5 ? cbrt(2 * gain) / 2: 1 - cbrt(2 * (1 - gain)) / 2;
    break;
case DESI:
    gain = gain <= 0.5 ? CUBE(2 * gain) / 2: 1 - CUBE(2 * (1 - gain)) / 2;
    break;
}

他们看起来怎么样？它们听起来怎么样？淡入淡出和交叉淡入淡出推荐哪一种？就我个人而言，我只是想避免音频点击，也许交叉淡入淡出在这里有点矫枉过正。

相关链接: http://manual.audacityteam.org/man/fade_and_crossfade.html .不确定如何大胆的名称转换为 ffmpeg 名称。

Answer 1

您可以在此处找到所有不同渐变曲线的图:

https://trac.ffmpeg.org/wiki/AfadeCurves