---
Daniel Oberhoff
daniel.oberh...@gmail.com
On Aug 20, 2014, at 2:17 PM, Michael Niedermayer <michae...@gmx.at> wrote:
> The only remaining floats are in the user interface, they are left as they
> should not cause a problem in practice
> ---
> libavfilter/vf_lenscorrection.c | 13 +++++++------
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/libavfilter/vf_lenscorrection.c b/libavfilter/vf_lenscorrection.c
> index 11fa4c8..d30a81b 100644
> --- a/libavfilter/vf_lenscorrection.c
> +++ b/libavfilter/vf_lenscorrection.c
> @@ -149,8 +149,8 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
> int h = rect->height / vdiv;
> int xcenter = rect->cx * w;
> int ycenter = rect->cy * h;
> - float k1 = rect->k1;
> - float k2 = rect->k2;
> + int k1 = rect->k1 * (1<<24);
> + int k2 = rect->k2 * (1<<24);
> ThreadData td = {
> .in = in,
> .out = out,
> @@ -162,7 +162,7 @@ static int filter_frame(AVFilterLink *inlink, AVFrame *in)
>
> if (!rect->correction[plane]) {
> int i,j;
> - const float r2inv = 4.0 / (w * w + h * h);
> + const int64_t r2inv = (4LL<<60) / (w * w + h * h);
>
> rect->correction[plane] = av_malloc_array(w, h *
> sizeof(**rect->correction));
> if (!rect->correction[plane])
> @@ -172,9 +172,10 @@ static int filter_frame(AVFilterLink *inlink, AVFrame
> *in)
> const int off_y2 = off_y * off_y;
> for (i = 0; i < w; i++) {
> const int off_x = i - xcenter;
> - const float r2 = (off_x * off_x + off_y2) * r2inv;
> - const float radius_mult = 1.0f + r2 * k1 + r2 * r2 * k2;
> - rect->correction[plane][j * w + i] = lrintf(radius_mult
> * (1<<24));
> + const int64_t r2 = ((off_x * off_x + off_y2) * r2inv +
> (1LL<<31)) >> 32;
won’t this potentially overflow for large off_x if int is 32bit? (same above
for off_y2)
> + const int64_t r4 = (r2 * r2 + (1<<27)) >> 28;
> + const int radius_mult = (r2 * k1 + r4 * k2 + (1LL<<27) +
> (1LL<<52))>>28;
> + rect->correction[plane][j * w + i] = radius_mult;
> }
> }
> }
> --
> 1.7.9.5
>
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