[FFmpeg-devel] [PATCH 10/11] dca: factorize scaling in inverse ADPCM

[Christophe Gisquet]

2014-02-07 Michael Niedermayer <michaelni at gmx.at>:
> should be ok though theres some further portntial for optimizations
> like the first iteration could be done with sum = instead of +=
> the adpcm_vb[s->prediction_vq[k][l]] and &subband_samples[k][l][m] and
> &s->subband_samples_hist[k][l][m+4]
> could be factored out

I'll think about it. We can wait on that one too.

> the / 8192 could be changed to * (1.0 / 8192)

I actually noticed that when browsing through disassembled code.

> some compilers will do some of these automatically though

Not gcc 4.6 (at least for x64, it generates a divss). I was wondering
how ldexpf was implemented but that's always a function call to libm.

We assume IEEE754 32bits floats already, but I guess this is pushing
too far if we wanted to only manipulate the exponent.

-- 
Christophe