[FFmpeg-devel] [PATCH] Move param initialization and colorspace details from sws_getContext() to sws_init_context().

[Stefano Sabatini]

On date Friday 2010-10-01 21:19:45 +0200, Stefano Sabatini encoded:
> On date Thursday 2010-09-30 01:34:14 +0200, Michael Niedermayer encoded:
> > On Thu, Sep 30, 2010 at 12:56:20AM +0200, Stefano Sabatini wrote:
> > > On date Wednesday 2010-09-29 19:25:28 +0200, Michael Niedermayer encoded:
> > > > On Wed, Sep 29, 2010 at 06:00:27PM +0200, Stefano Sabatini wrote:
> > > > > Allow to automatically set the default parameters without explicitely
> > > > > set them, also simplify conversion to the new sws_init_context() API.
> > > > > ---
> > > > >  utils.c |   18 +++++++-----------
> > > > >  1 files changed, 7 insertions(+), 11 deletions(-)
> > > > > 
> > > > > diff --git a/utils.c b/utils.c
> > > > > index 938af9e..bee5a3a 100644
> > > > > --- a/utils.c
> > > > > +++ b/utils.c
> > > > > @@ -761,10 +761,17 @@ int sws_init_context(SwsContext *c, SwsFilter *srcFilter, SwsFilter *dstFilter)
> > > > >      int dstW= c->dstW;
> > > > >      int dstH= c->dstH;
> > > > >      int flags;
> > > > > +    c->srcRange = handle_jpeg(&c->srcFormat);
> > > > > +    c->dstRange = handle_jpeg(&c->dstFormat);
> > > > 
> > > > that breaks user setted *Range
> > > 
> > > I'm aware but I cannot see a simpler way. A possibility would be to
> > > introduce an hack external to this function, but then doesn't look
> > > that good as well.
> > > 
> > > The problem is: how should the new API deal with JPEG colorspaces?
> > > Currently when we want to use the JPEG colorspace we pass one of the
> > > YUVJ* pixel formats. Avoiding this hack would mean to make the various
> > > FFmpeg components (well, mainly codecs) explicitely define which
> > > colorspace/range to use.
> > 
> > YUVJ* is deprecated
> > so designing new code toward it doesnt feel very good at all
> > 
> > also i dont see a problem
> > if YUVJ set Range appropriately
> > if not dont touch Range and leave it at the default / what the usert did set
> 
> Currently this has to be done directly in the application (in this
> case ffmpeg.c, right?), so I was thinking about creating a copy of
> handle_jpeg(), which is ugly, while it should be duty of libavcodec to
> do that, but I have yet to think which would be the better way.

More problems which should be addressed: libswscale only supports two
values for the color range, 0 and 1, libavcodec uses an enum
AVColorRange, so as the first thing libswscale should be updated
(would this comport a major break?).

Then we should update all the libavcodec code which doesn't set
adeguately the color_range.

Is this plan sound?

Regards.
-- 
FFmpeg = Frenzy and Fiendish Magical Philosofic Ermetic Geisha