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| author | Ganesh Ajjanagadde <gajjanagadde@gmail.com> | 2015-12-21 17:12:04 -0800 |
|---|---|---|
| committer | Ganesh Ajjanagadde <gajjanagadde@gmail.com> | 2015-12-23 09:22:59 -0800 |
| commit | 520a5d33f0ea9f8838dbc7282470db700d248065 (patch) | |
| tree | 4602726be342894896dbbe5af366ba3c05185ef0 | |
| parent | a0ec4aebabe1f816cc69e20309981907ba5d1395 (diff) | |
| download | ffmpeg-520a5d33f0ea9f8838dbc7282470db700d248065.tar.gz | |
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 <onemda@gmail.com>
Signed-off-by: Ganesh Ajjanagadde <gajjanagadde@gmail.com>
| -rwxr-xr-x | configure | 1 | ||||
| -rw-r--r-- | libavfilter/af_aemphasis.c | 13 |
2 files changed, 6 insertions, 8 deletions
@@ -2836,7 +2836,6 @@ unix_protocol_deps="sys_un_h" unix_protocol_select="network" # filters -aemphasis_filter_deps="cabs cexp" amovie_filter_deps="avcodec avformat" aresample_filter_deps="swresample" ass_filter_deps="libass" 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 <complex.h> - #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) |