[FFmpeg-devel] [PATCH] vorbis_enc.c: avoid div zero that causes noise

[Frank Barchard]

On Tue, Jun 1, 2010 at 6:01 PM, Michael Niedermayer <michaelni at gmx.at>wrote:

> On Tue, Jun 01, 2010 at 02:10:54PM -0700, Frank Barchard wrote:
>
> On Tue, Jun 1, 2010 at 12:39 PM, Michael Niedermayer <michaelni at gmx.at>
> >  wrote:
> > > does
> > > average= sqrt(tot_average * average) *  pow(1.25, position*0.005)
> > >
> > > work as well (without the 0 special casing of course) ?
>

It does.  Much nicer, thanks.

Index: libavcodec/vorbis_enc.c
===================================================================
--- libavcodec/vorbis_enc.c     (revision 23412)
+++ libavcodec/vorbis_enc.c     (working copy)
@@ -681,7 +681,7 @@
         float average = averages[i];
         int j;

-        average *= pow(tot_average / average, 0.5) * pow(1.25,
position/200.); // MAGIC!
+        average = sqrt(tot_average * average) * pow(1.25f,
position*0.005f); // MAGIC!
         for (j = 0; j < range - 1; j++)
             if (ff_vorbis_floor1_inverse_db_table[j * fc->multiplier] >
average)
                 break;
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