[MEncoder-users] Audio sync problem

[Owen Williams]

On Wed, 2009-09-09 at 14:33 +0200, belcampo wrote:
> > Freeview can/will have multiple aspect ratios in the recording so no
> > matter what which format I'd like to have the picture centered in
> the
> > image with appropriate black borders for that aspect ratio at that
> > moment in the stream.
> I don't think that is possible. AFAIK all encoders detect aspect
> ratio 
> and use that from start till end. If you want 4:3 in 16:9 aspect
> you'll 
> have to add blackborders explicitely.

I thought I had the magic right but this is the result after subsequent
aspect ratio changes (for each advert in the film:

http://ocean.blue.dmu.ac.uk/~williams/Film4/01.jpg
http://ocean.blue.dmu.ac.uk/~williams/Film4/02.jpg
http://ocean.blue.dmu.ac.uk/~williams/Film4/03.jpg
http://ocean.blue.dmu.ac.uk/~williams/Film4/04.jpg
.
.
until
.
.
http://ocean.blue.dmu.ac.uk/~williams/Film4/09.jpg

The image gets smaller and smaller...

Does anyone know a better magic than:

-vf yadif,expand=:::::16/9,scale=1024:576,harddup

or an approach that would work most of the time to discover what is the
main aspect ratio of the material recorded?

Any help much appreciated,

Owen.