[FFmpeg-devel] [PATCH] avcodec/opus_celt: replace pow by exp2

[Paul B Mahol]

On 12/17/15, Ganesh Ajjanagadde <gajjanagadde at gmail.com> wrote:
> exp2 is faster.
>
> Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
> ---
>  libavcodec/opus_celt.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/libavcodec/opus_celt.c b/libavcodec/opus_celt.c
> index 9911de3..474452f 100644
> --- a/libavcodec/opus_celt.c
> +++ b/libavcodec/opus_celt.c
> @@ -1677,7 +1677,7 @@ static void celt_denormalize(CeltContext *s, CeltFrame
> *frame, float *data)
>
>      for (i = s->startband; i < s->endband; i++) {
>          float *dst = data + (celt_freq_bands[i] << s->duration);
> -        float norm = pow(2, frame->energy[i] + celt_mean_energy[i]);
> +        float norm = exp2(frame->energy[i] + celt_mean_energy[i]);
>
>          for (j = 0; j < celt_freq_range[i] << s->duration; j++)
>              dst[j] *= norm;
> @@ -1857,7 +1857,7 @@ static void process_anticollapse(CeltContext *s,
> CeltFrame *frame, float *X)
>
>          /* r needs to be multiplied by 2 or 2*sqrt(2) depending on LM
> because
>          short blocks don't have the same energy as long */
> -        r = pow(2, 1 - Ediff);
> +        r = exp2(1 - Ediff);
>          if (s->duration == 3)
>              r *= M_SQRT2;
>          r = FFMIN(thresh, r) * sqrt_1;
> --
> 2.6.3
>
> _______________________________________________
> ffmpeg-devel mailing list
> ffmpeg-devel at ffmpeg.org
> http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
>

should be ok iff fate passes.