[CELT-dev] Variable frame size and API changes

Bob Bang bob.bang2 at gmail.com
Wed May 19 07:49:39 PDT 2010


in regards to your oversampling idea, the extra processing required may
nullify the gains from using DSPLIB over kissfft.

To be honest, I have not measured the MIPS difference between DSPLIB and
kiss FFT, I will try to do that sometime soon to see how much of a
difference the intrinsic libraries make. Do you have those numbers already?

2010/5/18 Jean-Marc Valin <Jean-Marc.Valin at usherbrooke.ca>

> Hi Bob,
> A few questions/comments:
> 1) It may be possible to use the TI DSP for all of the radix-2 steps in the
> and then only apply the radix 3 and 5 in C.
> 2) I assume that the sampling is done on the TI chip, so couldn't you just
> configure it to work at 51.2 kHz? This would produce frames that are powers
> of
> two and the resulting bit-stream would be perfectly compatible with a
> decoder
> running with the same frame duration (hence 15/16 the actual number of
> samples)
> at 48 kHz.
> Cheers,
>   Jean-Marc
> Quoting Bob Bang <bob.bang2 at gmail.com>:
> > Hello Jean-Marc, I appreciate you taking our feedback in this change.
> >
> > I would be against this new input frame size change as I am developing on
> > the TI 55x platform.  On this platform it benefits to use the DSPLIB
> which
> > REQUIRES a power of 2 frame size.
> >
> > My current setup is using a 48kHz sample rate and a 128 sample frame size
> > (~2.5ms).
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