[FFmpeg-devel] lavfi state of affairs

[Stefano Sabatini]

On date Friday 2009-02-06 01:24:34 +0100, Michael Niedermayer encoded:
> On Thu, Feb 05, 2009 at 11:57:42PM +0100, Stefano Sabatini wrote:
> > On date Thursday 2009-02-05 14:28:05 -0800, Baptiste Coudurier encoded:
> > > On 2/5/2009 2:02 PM, Michael Niedermayer wrote:
> > > > On Thu, Feb 05, 2009 at 12:36:55PM -0800, Baptiste Coudurier wrote:
> > [...]
> > > >> I asked you several times what was needed to actually _do_ this.
> > > >
> > > > cleanup the command line parsing code and submit a patch.
> > > 
> > > Okey this is constructive. Stefano can you comment on this ?
> > 
> > Well, one of the problem is that currently in libavfilter-soc it's not
> > possible to select the sws_scale flags (which is possible in the
> > official SVN), furthermore is not possible to set the other swscale
> > context parameters as well.
> > 
> > One of the side-effects of this is that regression tests don't pass in
> > libavfilter-soc, but the problem here is that we need to find some way
> > to specify the swscale parameters (flags + filter vectors + whatever)
> > in the command line then pass them to the vf_scale filter.
> 
> hmm, i see now that AVOptions with sws is slightly unpretty, it seems i didnt
> realize this previously, ill look at your patch (i think there was one)
> itmight not have been that bad ...
> 
> to make AVOptions work nicer the sws init should possibly be split so
> that the context is allocated then the user (via AVOptions) has a chance
> to set various values and then the actual init is done.

Yes, maybe something like:

struct SwsContext *sws = sws_allocContext();

/* fill the context with AVOptions... */

sws->flags = ...;

if (sws_initContext(sws) < 0)
   failed...
else
   ...

> > 
> > Then I stumbled across libswscale and I'm still there (I even have a
> > documentation patch for it, but I don't want to post it before to have
> > a better grasp of it).
> > 
> > Related thread:
> > http://thread.gmane.org/20090122230630.GC621 at geppetto
> > 
> > Another big problem which I already mentioned in this thread is that
> > slicification doesn't work when converting the format, for example:
> > ffplay -f video4linux /dev/video -s 640x480 -vfilters  "slicify=16, format=rgb32"
> 
> try with and without scaling do both fail? does rgb32 outputfail for all
> input pixfmts?

Yes I tried with all the input formats and output formats, the only
one which seems to work is yuv420p.

Also things like this seems not to work
ffplay -f video4linux /dev/video -vfilters  "format=rgb32, slicify=32, format=rgb32"
ffplay -f video4linux /dev/video -vfilters  "format=rgb32, slicify=32, scale=160:120, format=rgb32"
ffplay -f video4linux /dev/video -vfilters  "format=rgb32, scale=160:120, slicify=32, format=rgb32"

I'll try to debug it in the weekend.

Regards. 
-- 
FFmpeg = Faboulous and Fiendish Most Philosofic Encoding/decoding God