[FFmpeg-devel] [PATCH 2/3] Indeo 5 decoder: common DSP functions
Sun Jan 17 14:06:40 CET 2010
On Sun, Jan 10, 2010 at 01:22:17PM +0200, Kostya wrote:
> On Sat, Jan 09, 2010 at 05:43:40PM +0200, Kostya wrote:
> > On Sat, Jan 09, 2010 at 03:47:39PM +0100, Michael Niedermayer wrote:
> > > On Sat, Jan 09, 2010 at 04:40:30PM +0200, Kostya wrote:
> > > > On Fri, Jan 08, 2010 at 11:41:23PM +0100, Michael Niedermayer wrote:
> > > > > On Sun, Jan 03, 2010 at 12:56:36PM +0200, Kostya wrote:
> > > > > [...]
> > > > > > void ff_ivi_recompose53(const IVIPlaneDesc *plane, uint8_t *dst,
> > > > [function body skipped]
> > > > >
> > > > > is this mess faster than some more readable variant?
> > > >
> > > > Here's more readable variant by me, checked to be bitexact but it's
> > > > significantly slower (> 10%), I'd rather leave old one.
> > >
> > > I also prefer speed, what about an implementation using lifting?
> > I'll try to implement it.
> Hmm, after some experiments I'd rather leave original version.
> Even grouping variables together in array gives significant performance
> drop. And pure lifting transform is not applicable here either because
> band data is grouped and it will take at least two passes (hor/vert)
> with conditions for missing bands and requires an additional temp
I've tried reusing Snow wavelet composing there. It was several percents
slower which is not surprising because it needs an intermediate buffer
there and Indeo5 code does not need to check for odd dimensions.
More information about the ffmpeg-devel