[FFmpeg-devel] [PATCH] [3/3] SIPR 16k decoder

Michael Niedermayer michaelni
Fri Jan 15 01:32:41 CET 2010

On Thu, Jan 14, 2010 at 07:30:16PM -0500, Ronald S. Bultje wrote:
> Hi,
> On Thu, Jan 14, 2010 at 7:25 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Thu, Jan 14, 2010 at 07:19:47PM -0500, Ronald S. Bultje wrote:
> >> On Thu, Jan 14, 2010 at 7:05 PM, Vitor Sessak <vitor1001 at gmail.com> wrote:
> >> > The rule I use is: always use floats, unless when you need to call
> >> > ff_acelp_lspd2lpc(), which takes doubles as arguments (and also to
> >> > avoiding converting buffers to double or back).
> >>
> >> So let's change ff_acelp_lspd2lpc()? Why does it use doubles?
> >
> > dont forget testing PSNR & with yor ears if PSNR differs
> >
> > i remember this double vs float discussion and the last time the awnser IIRC
> > was that floats are not accurate enough. I dont want to see the floats are
> > faster on my system so change it discussion repeat until testing is forgotten
> > and we put a possibly hard to debug bug in
> My point is more or less that *ALL* voice decoders should use doubles
> everywhere. The 16k code uses floats, takes a cos(f), casts it to a
> double and suddenly we have a double. That's not right. It should've
> used doubles from the beginning if the goal was to do a double.
> And why on earth are LPCs in float if LSPs are in double?

doubles should be used only when we need the precission, reason is speed


Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

If you think the mosad wants you dead since a long time then you are either
wrong or dead since a long time.
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