[OE-core] Enabling x264 support in gstreamer

[Phil Blundell]

On Tue, 2013-08-13 at 13:26 -0600, Gary Thomas wrote:
> On 2013-08-13 11:36, Martin Jansa wrote:
> > On Tue, Aug 13, 2013 at 11:29:10AM -0600, Gary Thomas wrote:
> >> I see that some of the gstreamer recipes have changed so that x264
> >> is now a PACKAGECONFIG option.  However, I don't see anything that
> >> enables this option anywhere.
> >>
> >> How do I get x264 support back - it was working with Poky/Yocto
> >> just a few weeks back...
> >>
> >> Note: I have imported meta-oe/recipes-multimedia/x264 from meta-openembedded
> >> into my layers for this [library] package.
> >
> > Add x264 to PACKAGECONFIG in your .bbappend or distro config as
> > PACKAGECONFIG_append_pn-gst-foo = " x264"
> 
> Thanks, although this seems very cumbersome to me.  Is this the only
> (or at least expected) way for this to work?

Well, if it's in a .bbappend (rather than distro.conf) then you don't
need the _append_pn-gst-foo bit, you can just write

PACKAGECONFIG += "x264"

which is probably a bit neater and more intuitive.  But if you don't
already have a .bbappend for that recipe then you might not want to add
one just for that, it's just a matter of taste which you prefer.

Other than that, yes, this is basically how PACKAGECONFIG is intended to
be used.  Some recipes set a default PACKAGECONFIG based on
DISTRO_FEATURES, but in the general case it's just a variable that you
need to set appropriately.

The thing that's a bit unsatisfactory about this approach is that we
don't have any equivalent to DISTRO_FEATURES_BACKFILL for recipe-local
PACKAGECONFIG options, which means that introducing new switches for
things that were previously default-on tends to cause unexpected
breakage of the sort that you've observed.  It would be good to figure
out a better way of dealing with that.

p.