[FFmpeg-devel] [PATCH] all: use predefined mathematics macros

[Paul B Mahol]

On 11/11/15, Ganesh Ajjanagadde <gajjanagadde at gmail.com> wrote:
> This uses M_SQRT2, M_PI, and M_E instead of the actual literals.
> Benefits include:
> 1. Reduced scope for copy/paste errors and improved readability.
> 2. Consistency across the codebase.
> 3. Actually fixes an incorrect sqrt(2) in avcodec/ppc.
> 4. Greater precision in avcodec/ac3.
>
> Patch tested with FATE on x86, ppc untested.
>
> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> ---
>  libavcodec/ac3.h                   |  2 +-
>  libavcodec/cos_tablegen.c          |  4 +++-
>  libavcodec/mpegaudioenc_template.c |  4 ++--
>  libavcodec/mpegaudiotab.h          |  2 --
>  libavcodec/mpegvideo.c             |  4 ++--
>  libavcodec/ppc/fdctdsp.c           | 21 ++++++++++-----------
>  libavcodec/ratecontrol.c           |  4 ----
>  libavcodec/simple_idct.c           |  4 ++--
>  libavfilter/af_dynaudnorm.c        |  4 +---
>  9 files changed, 21 insertions(+), 28 deletions(-)
>

[...]

> diff --git a/libavfilter/af_dynaudnorm.c b/libavfilter/af_dynaudnorm.c
> index 8f0c2d0..62a2653 100644
> --- a/libavfilter/af_dynaudnorm.c
> +++ b/libavfilter/af_dynaudnorm.c
> @@ -227,8 +227,6 @@ static int cqueue_pop(cqueue *q)
>      return 0;
>  }
>
> -static const double s_pi =
> 3.1415926535897932384626433832795028841971693993751058209749445923078164062862089986280348253421170679;
> -
>  static void init_gaussian_filter(DynamicAudioNormalizerContext *s)
>  {
>      double total_weight = 0.0;
> @@ -238,7 +236,7 @@ static void
> init_gaussian_filter(DynamicAudioNormalizerContext *s)
>
>      // Pre-compute constants
>      const int offset = s->filter_size / 2;
> -    const double c1 = 1.0 / (sigma * sqrt(2.0 * s_pi));
> +    const double c1 = 1.0 / (sigma * sqrt(2.0 * M_PI));

Please leave this one as it is.

>      const double c2 = 2.0 * pow(sigma, 2.0);
>
>      // Compute weights