[FFmpeg-devel] discussion around the best way to patch the swscale for Blackfin

[Michael Niedermayer]

Hi

On Thu, Jun 21, 2007 at 11:00:28PM -0400, Marc Hoffman wrote:
> On 6/14/07, Marc Hoffman <mmhoffm at gmail.com> wrote:
> >
> >
> >
> >On 6/14/07, Reimar Doeffinger <Reimar.Doeffinger at stud.uni-karlsruhe.de>
> >wrote:
> >>
> >> Hello,
> >> On Thu, Jun 14, 2007 at 03:00:44PM -0400, Marc Hoffman wrote:
> >> [...]
> >> > What do you mean "doesn't allow to use special bfin converters only
> >> for some
> >> > colourspaces"?
> >>
> >> I mean that above where you inserted you new code there is e.g.:
> >> c->swScale= gray16swap;
> >> With your patch, this gray16swap will never be used for colourspace
> >> conversion on blackfin, even if you do not have an optimized variant of
> >> it (unless you also duplicate the selection code for non-optimzed
> >> conversion in you new function, I can't know that from your patch of
> >> course ;-) ).
> >
> >
> >
> >I think we are on the same page.
> >
> >I guess I was thinking that the  my function could choose to override but
> >it doesn't need to do that.  The semantics of the function I would define
> >would be something like this.
> >
> >SwsFunc ff_bfin_get_unscaled_swscale (SwsContext *c)
> >{
> >  SwsFunc swScale = c->swScale;
> >  if ((c->flags & SWS_CPU_CAPS_BFIN) &&
> >      ((c->dstFormat == PIX_FMT_YUV420P &&
> >    (c->srcFormat == PIX_FMT_YUYV422 || c->srcFormat ==
> >PIX_FMT_UYVY422)))) {
> >    return ff_bfin_yuy2toyv12_unscaled;
> >  }
> >  return c->swScale;
> >}
> >
> >
> >This way I can freely add optimizations for Blackfin with out changing the
> >existing infastructure. I guess in a sense its much like what the dsputils
> >do right now.
> >
> >Maybe I should just do this in swscale
> >
> >#ifdef ARCH_BFIN
> >    ff_bfin_get_unscaled_swscale (c);
> >#endif
> >
> >And just do the following?
> >
> >void ff_bfin_get_unscaled_swscale (SwsContext *c)
> >{
> >  SwsFunc swScale = c->swScale;
> >  if ((c->flags & SWS_CPU_CAPS_BFIN) &&
> >      ((c->dstFormat == PIX_FMT_YUV420P &&
> >    (c->srcFormat == PIX_FMT_YUYV422 || c->srcFormat ==
> >PIX_FMT_UYVY422)))) {
> >    c->swScale = ff_bfin_yuy2toyv12_unscaled;
> >  }
> >}
> >
> >Now that you came up with a bit of confusion I'm thinking the later might
> >be a better choice for us.
> 
> 
> 
> Does this look like a clean integration for the unscaled variant for the
> swscale infrastructure?  Seems reasonably clean to me but another set of
> eyes would be great.

looks ok

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

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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