[FFmpeg-devel] [PATCH] Fix for inverted sign in?ffvorbis?audio?output (resubmit)

Siarhei Siamashka siarhei.siamashka
Sat May 16 10:25:13 CEST 2009


On Friday 15 May 2009, Michael Niedermayer wrote:
> On Fri, May 15, 2009 at 10:52:05AM +0300, Siarhei Siamashka wrote:
[...]
> > Would this patch be finally OK (kind of blend of your and Reimar's
> > suggestions)?
>
> [...]
>
> > @@ -85,10 +85,12 @@ av_cold int ff_mdct_init(MDCTContext *s, int nbits,
> > int inverse) if (!s->tsin)
> >          goto fail;
> >
> > +    theta = scale < 0 ? 0.5 * M_PI : 0;
> > +    scale = sqrt(fabs(scale));
> >      for(i=0;i<n4;i++) {
> > -        alpha = 2 * M_PI * (i + 1.0 / 8.0) / n;
> > -        s->tcos[i] = -cos(alpha);
> > -        s->tsin[i] = -sin(alpha);
> > +        alpha = 2 * M_PI * (i + 1.0 / 8.0) / n + theta;
>
> alpha = 2 * M_PI * (i + theta) / n;
>
> would be slightly more accurate as (i + theta) / n is exact and thus
> the addition of two inexact variables is avoided

Fixed

-- 
Best regards,
Siarhei Siamashka
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