[FFmpeg-devel] [PATCH] Make h264idct.c compilation optional

Michael Niedermayer michaelni
Tue May 22 23:04:18 CEST 2007


Hi

On Tue, May 22, 2007 at 07:42:04PM +0200, Aurelien Jacobs wrote:
> On Tue, 22 May 2007 11:23:15 +0200
> Panagiotis Issaris <takis.issaris at uhasselt.be> wrote:
> 
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> > 
> > Hi,
> > 
> > Panagiotis Issaris wrote:
> > > Loren Merritt wrote:
> > >> On Mon, 14 May 2007, Aurelien Jacobs wrote:
> > >>> Panagiotis Issaris wrote:
> > >>>
> > >>>> The attached patch tries to make the h264idct.c compilation optional.
> > >>>> Not meant for direct inclusion, as I am not sure about the correctness...
> > >>>>
> > >>>> In dsputil_init() currently [1], for lowres decoding, when idct_algo's
> > >>>> other than FF_IDCT_INT or FF_IDCT_AUTO are selected, h264 related
> > >>>> functions (ff_h264_lowres_idct_put|add_c) are being used. Are these two
> > >>>> functions in fact more generic then their name implies (in fact just
> > >>>> misnamed), and should they be relocated to some other common file?
> > >>>>
> > >>>> Or are they really H.264 specific functions? ... but in that case it
> > >>>> seems weird that selecting f.e. FF_IDCT_VP3 or FF_IDCT_SIMPLEMMX would
> > >>>> result in using these H.264 specific functions.
> > >>> Patch seems ok, but I also would like to hear first what's the purpose
> > >>> of ff_h264_lowres_idct_put/add_c (is it h264 only or more general ?).
> > >> ff_h264_lowres_idct* are not used in h264. They're so named because 
> > >> they apply h264's idct algo to other codecs, when whe user requests 
> > >> non-standards-compliant speedups. They're not the default because they're 
> > >> even less precise than the other lowres idct.
> > > 
> > > I see; thanks for the explanation.
> > > 
> > > So, I could:
> > > * Move both functions to dsputil.c as they are only used there.
> > > * Keep them in h264idct.c, but disable their usage when H.264 decoder
> > > support is not compiled in. This shouldn't break anything as in that
> > > case ff_jref_idct4_put() would be used instead for lowres==1.
> > > 
> > > Any opinions?
> > 
> > This is an updated patch of above mentioned option 2, which was what the
> > patch that started this thread did.
> 
> After some thought, this solution looks ok to me.
> Michael ?

ok

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

It is dangerous to be right in matters on which the established authorities
are wrong. -- Voltaire
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