[FFmpeg-devel] [RFC] ac3dec: use dsputil.clear_block
Thu Jan 14 01:28:24 CET 2010
On Wed, Jan 13, 2010 at 06:32:27PM -0500, Justin Ruggles wrote:
> Reimar D?ffinger wrote:
> > On Wed, Jan 13, 2010 at 11:42:27PM +0100, Michael Niedermayer wrote:
> >> On Wed, Jan 13, 2010 at 09:46:17PM +0100, Reimar D?ffinger wrote:
> >>> Hello,
> >>> this gives an overall speedup of about 1.1 % on Intel Atom with my sample.
> >>> Testing with other CPUs and samples heavily welcome, I suspect a slowdown may
> >>> be possible, beside it being a bit ugly.
> >> what happens with these coeffs afterwards?
> >> is it
> >> s->dsp.int32_to_float_fmul_scalar(s->transform_coeffs[ch], s->fixed_coeffs[ch], gain, 256);
> >> ?
> >> if so maybe that could be changed to not touch the supposed to be zero
> >> coeffs?
> > I had that idea as well, but I have to admit I do not know, nor if I will have the time
> > to understand the code well enough to know :-)
> Yes the only time they're used is when they're converted to float. If
> we don't zero the integer coeffs, we will need to zero the float coeffs
> because the IMDCT uses all 256.
are the float coeffs ever written to besides in int32_to_float_fmul_scalar ?
because if not you could keep track of the last non zero coeff and just
zero upto that each time
Michael GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB
Democracy is the form of government in which you can choose your dictator
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