[FFmpeg-devel] [PATCH] Channels correlation

Jai Menon jmenon86
Sat Oct 31 08:33:08 CET 2009


On Fri, Oct 30, 2009 at 03:34:22PM +0100, Nicolas George wrote:
> Le nonidi 9 brumaire, an CCXVIII, Michael Niedermayer a ?crit?:
> > yes, your "transposed from what i expect" matrix confused me (thats my
> > problem i know). But isnt it faster the other way around? that loop reimar
> > complained about would then be along consecutive elements.
> 
> I just tried: it is not faster, but it a bit more readable (especially the
> pivot), so I kept it.
> 
> > What concerns me is that your code and lls do the same thing, and i dont
> > see why we would need another implementation of this code.
> > If the lls API is poor, maybe it can be improved rather than another lls
> > implementation being added inside a muxer?
> 
> That is a perfectly valid concern indeed.
> 
> The lls.h API is used inside the main function of two encoders for pupular
> formats (FLAC and ALAC), so it makes sense to seek speed rather than generic
> code.

Just wanted to point out that though in the case of the flac encoder
the lls code can be used (through the external option use_lpc), the
alac encoder doesnt use lls at all. So if you do end up running
benchmarks, you might want to restrict yourself to the flac encoder to
save time ;)

-- 
Jai Menon




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