From 520a5d33f0ea9f8838dbc7282470db700d248065 Mon Sep 17 00:00:00 2001 From: Ganesh Ajjanagadde Date: Mon, 21 Dec 2015 17:12:04 -0800 Subject: lavfi/af_aemphasis: remove unnecessary complex number usage complex is not available on all platforms. Furthermore, it is trivial to rewrite complex number expressions to real arithmetic, and in fact sometimes advantageous for performance reasons: by wrapping as a complex, one forces a particular Cartesian representation that is not necessarily optimal for the purpose. Configure dependencies also removed, and aemphasis is now available across all platforms. Reviewed-by: Paul B Mahol Signed-off-by: Ganesh Ajjanagadde --- libavfilter/af_aemphasis.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) (limited to 'libavfilter/af_aemphasis.c') diff --git a/libavfilter/af_aemphasis.c b/libavfilter/af_aemphasis.c index 2966f7721f..a5b8e3058a 100644 --- a/libavfilter/af_aemphasis.c +++ b/libavfilter/af_aemphasis.c @@ -18,8 +18,6 @@ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ -#include - #include "libavutil/opt.h" #include "avfilter.h" #include "internal.h" @@ -189,14 +187,15 @@ static inline void set_lp_rbj(BiquadD2 *bq, double fc, double q, double sr, doub static double freq_gain(BiquadCoeffs *c, double freq, double sr) { - double complex z, w; + double zr, zi; freq *= 2.0 * M_PI / sr; - w = 0 + I * freq; - z = 1.0 / cexp(w); + zr = cos(freq); + zi = -sin(freq); - return cabs(((double complex)c->a0 + c->a1 * z + c->a2 * z*z) / - ((double complex)1.0 + c->b1 * z + c->b2 * z*z)); + /* |(a0 + a1*z + a2*z^2)/(1 + b1*z + b2*z^2)| */ + return hypot(c->a0 + c->a1*zr + c->a2*(zr*zr-zi*zi), c->a1*zi + 2*c->a2*zr*zi) / + hypot(1 + c->b1*zr + c->b2*(zr*zr-zi*zi), c->b1*zi + 2*c->b2*zr*zi); } static int config_input(AVFilterLink *inlink) -- cgit v1.2.3