[FFmpeg-devel] [PATCH] G.729A (floating-point) decoder and ACT demuxer
Tue Feb 26 04:11:07 CET 2008
On Tue, Feb 26, 2008 at 3:09 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> On Mon, Feb 25, 2008 at 08:53:44PM +0600, Vladimir Voroshilov wrote:
> > On Sun, Feb 24, 2008 at 11:48 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > >
> > > Why would we choose the floating point approximation if we can have an
> > > exact integer implementation ?
> > My skills are enough only for either cleanup current (working)
> > floating-point code or 'port' (remove globals, fix data types, write
> > interface to FFmpeg internals) reference code to ffmpeg.
> > Thus, in fixed-point case, code will be 95% the same as reference.
> Where is the problem with taking the L1/L2/L3 tables from the fixed point
> implementation? They should be the same as the float ones obviously just
> with different scaling.
They (float and converted fixed-point) differs starting from 4th of
5th sign after comma.
> Have you tried? Does it fail? Are you too lazy to try?
I didn't tried to use tables 'as-is' (i converted them to float first)
and they of course works. Just thought that reference float tables
will be more precise in floating point code.
I can't say right now are they really better in current floating code
or not, because
removed them (while fixing error) before i found last error.
I'l try to put those tables back.
I should compare differences (both float and fixed-point tables) with
fixed-point reference code, right?
I'll do checks as soon as possible and give you results of tiny_psnr, ok ?
Vladimir Voroshilov mailto:voroshil at gmail.com
JID: voroshil at gmail.com, voroshil at jabber.ru
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