[FFmpeg-devel] [PATCH] Common ACELP routines (2/3) - filters
Sat Apr 26 20:05:32 CEST 2008
On Sun, Apr 27, 2008 at 12:41 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Sat, Apr 26, 2008 at 11:11:56PM +0700, Vladimir Voroshilov wrote:
> > On Fri, Apr 25, 2008 at 6:16 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > [...]
> > > Yes thats also what i thought at first but vladimirs insistance made
> > > me belive that the output of this function would be the final audio
> > > samples returned from "decode_audio". In which cases one of course
> > > cannot have 10 samples before it.
> > > Now after looking at the actual code its clear that there are always
> > > some other filters applied afterwards. So i agree, none of this makes
> > > sense, no double writing, no special case for the first "10" samples
> > > nor a memcpy() should be needed. Except a memcpy to move the first
> > > "10" samples to the buffer start.
> > To tell the truth i didn't understand should i fix patch somehow or
> > not according to above.
> ff_acelp_lp_synthesis_filter_inplace() is exactly what we need,
> ff_acelp_lp_synthesis_filter() is unneeded, please remove it.
> > After splitting ff_acelp_lp_synthesis_filter, one of routines still
> > requires additional 10 items in filter data. It is possible to avoid
> > such requirement in cost of additional 20 bytes long memcpy.
> > But i don't know will this improve something or not.
> Only a single memcpy() of 10 elements is needed.
> memcpy(buf, buf+N, 10);
> overflow= acelp_lp_synthesis_filter(buf+10, input, N);
> for(i=0; i<N; i++)
> acelp_lp_synthesis_filter(buf+10, input, N);
buf is subframe_size+10 long as i see.
And this will require copy from buf to output_data
(explicit via memcpy or implicit, e.g. high-pass filter should put
data directly to output_data instead of it's input buffer)
Second is preferred, right?
> Ill review the rest later
Get updated patch from my reply to Diego's mail.
I want to hear your opinion about math-related comments as well.
Vladimir Voroshilov mailto:voroshil at gmail.com
JID: voroshil at gmail.com, voroshil at jabber.ru
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