[FFmpeg-devel] [PATCH] Common ACELP routines (2/3) - filters

Vladimir Voroshilov voroshil
Sat Apr 26 18:11:56 CEST 2008

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.

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.

What was done:
1. Changed fixed-point notation.

2. included high-pass filter there (used in post filtering stage).
Because even with non-equal float values in specifications (they differs in 5th
digit after decimal point) both G.729 and AMR  fixed-point
reference code  use the same constants in it.

P.S. Please anybody check English spelling too.

Vladimir Voroshilov mailto:voroshil at gmail.com
JID: voroshil at gmail.com, voroshil at jabber.ru
ICQ: 95587719
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