[Ffmpeg-devel] [PATCH] audio channel extraction

[Michael Niedermayer]

Hi

On Fri, Sep 15, 2006 at 06:08:06PM +0200, Axel Holzinger wrote:
> Hi
> 
> > Hi
> >
> > On Fri, Sep 15, 2006 at 02:21:13PM +0200, Baptiste Coudurier wrote:
> > > Michael Niedermayer wrote:
> > > > Hi
> > > >
> > > > On Fri, Sep 15, 2006 at 12:47:20PM +0200, Baptiste Coudurier wrote:
> > > >> Hi
> > > >>
> > > >> This patch adds feature to extract specific channels from
> > audio track.
> > > >> My main goal was to split 4 channels tracks to 2 stereos tracks.
> > > >
> > > > what about a more generic system which could mix chanels together into
> > > > other channels? so that there would be a AxB matrix of coefficients to
> > > > mix A input channels into B output channels?
> > > >
> > > >
> > > > [...]
> > >
> > > That would be a nice idea indeed, and would that be usefull for ac3/aac
> > > downmixing also ?
> >
> > i think so
> >
> >
> > > I might lack theory and good design skills to do that
> > > though :/
> > > Could you point me papers, or design ideas ?
> >
> > just leave the coefficients to the user as command line parameters
> 
> bad idea as the ac3 data already tells you how to downmix
> 
> or do you think the user shall read the ac3 data directly to find out how to
> downmix?

if a stream contains information on how to downmix and the number of channels
the user wants matches then this could be used as default if the user doesnt
specify any other coefficients

but extracting these coefficients from the stream and supporting downmixing
based on user specified coeffs are 2 seperate things

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

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