[FFmpeg-cvslog] r15151 - in trunk: configure libavcodec/Makefile

[Aurelien Jacobs]

On Wed, 3 Sep 2008 00:57:57 +0200
Diego Biurrun <diego at biurrun.de> wrote:

> On Wed, Sep 03, 2008 at 12:45:18AM +0200, Aurelien Jacobs wrote:
> > On Wed, 3 Sep 2008 00:27:56 +0200
> > Diego Biurrun <diego at biurrun.de> wrote:
> > 
> > > On Tue, Sep 02, 2008 at 10:54:53PM +0200, Aurelien Jacobs wrote:
> > > > On Tue, 2 Sep 2008 19:06:29 +0200
> > > > Diego Biurrun <diego at biurrun.de> wrote:
> > > > 
> > > > > On Tue, Sep 02, 2008 at 06:04:27AM +0200, jbr wrote:
> > > > > > 
> > > > > > Log:
> > > > > > add a separate line in Makefile for E-AC-3 decoder and only compile it when
> > > > > > GPL is enabled. fixes building without GPL or with liba52.
> > > > > > 
> > > > > > --- trunk/configure	(original)
> > > > > > +++ trunk/configure	Tue Sep  2 06:04:26 2008
> > > > > > @@ -848,6 +848,7 @@ byteswap_h_deps="!armv4l"
> > > > > >  # decoders / encoders
> > > > > >  ac3_decoder_deps="gpl !liba52"
> > > > > >  dxa_decoder_deps="zlib"
> > > > > > +eac3_decoder_deps="gpl"
> > > > > > 
> > > > > > --- trunk/libavcodec/Makefile	(original)
> > > > > > +++ trunk/libavcodec/Makefile	Tue Sep  2 06:04:26 2008
> > > > > > @@ -63,6 +63,7 @@ OBJS-$(CONFIG_DVDSUB_ENCODER)          +
> > > > > >  OBJS-$(CONFIG_DXA_DECODER)             += dxa.o
> > > > > > +OBJS-$(CONFIG_EAC3_DECODER)            += eac3dec.o ac3dec.o ac3tab.o ac3dec_data.o ac3.o mdct.o fft.o
> > > > > 
> > > > > I think it's easier to just make the E-AC-3 decoder depend on the AC-3
> > > > > decoder.
> > > > 
> > > > ./configure --enable-gpl --enable-decoder=eac3 --disable-decoder=ac3
> > > > works fine, and I see no valid reason to prevent it
> > > 
> > > Small wonder - these flags have no effect at all.
> > 
> > They have an effect !
> > With this configure line the ac3_decoder won't be registered with
> > register_avcodec().
> > And thus CODEC_ID_AC3 won't be handled by any decoder.
> 
> Let me rephrase: They are pointless since the code is compiled, but the
> codec is not registered.  What for?

There isn't much reason to do this on purpose, except for controling
precisely which CODEC_ID you want that lavc accept decoding or not.
But this is not the point. Users don't know about all of that.
And some users will triger this situation, especially by disabling
everything and only enabling eac3 decoder. And I can't imagine
any valid argument why we should fail such a request. Is there any ?

Oh, and you propose to make eac3 depends on ac3, but why wouldn't
it be the opposit ? Why placing one of them in a favored situation ?
They should IMO be treated in a stricly equal way.
If one of this configuration works, there is no reason for the other
to fail:
./configure --enable-gpl --enable-decoder=eac3 --disable-decoder=ac3
./configure --enable-gpl --enable-decoder=ac3 --disable-decoder=eac3

Aurel