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

Ronald S. Bultje rsbultje
Fri Jan 15 01:37:22 CET 2010


On Thu, Jan 14, 2010 at 7:30 PM, Ronald S. Bultje <rsbultje at gmail.com> wrote:
> 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.

Let me rephrase this before I say more stupid things that I didn't
intend: if LSPs are double, then LSFs should be double also, and so
should the code generating them.

Secondly, if LSPs are double, why are LPCs not double?

Of course ACB/FCB generation and gain calculation can be done in float.


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