[MEncoder-users] Audio sync problem

belcampo belcampo at zonnet.nl
Wed Sep 9 17:24:53 CEST 2009


Owen Williams wrote:
> 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?
The simplest, although not the cheapest, way it can be done is by using 
a Hauppauge HD-PVR, where you can define the output format as 16:9 where 
4:3 material gets pillar-boxed.
Or output format is 4:3 and 16:9 format gets letterboxed.
The result will  be 1-format material in h264 format in an MPEG-TS 
container which eventually can be encoded to other wanted formats.

Or

cut your recorded stream to 'pieces' with the same properties. Play the 
file, determin the start en endposition which can be cutted with several 
packages like tsmuxer, projectx etc.
> 
> Any help much appreciated,
> 
> Owen.
> 
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