videocrop and videobox not working in video coordinate...

[Sebastian Dröge]

On Mi, 2014-01-22 at 09:59 +0100, Eric Trousset wrote:
> Hi,
> It looks like videocrop and videobox tries to negotiate the caps based on the output, thus negotiating a input of output size + cropping offsets.
> So if we have a 1920x1080 video that we want to render in a 320x200 surface, the videoxxx element will negociate an input of 320+left+rightx200+top+bottom.
> This doesn't really make sence IMO cause we want to crop a certain amount in the original video coordinate , so videoxxx should accept the full video size on input, crop it, and then we can do the videoscale to obtain the final video size.
> 
> Actually this is an issue only when using playbin, giving a custom videosink bin that has the videobox/crop element.
> 
> Is there a easy way to have the input negotiate the fullvideo size?

Well, that's how these elements work. They add or remove X pixels
to/from every border. Thus the output will be the same size as the input
with these changes. Which on the other hand means that if downstream can
only accept a single size, then the input will have to be that size with
the inverse changes of the videocrop/box element.

You'll have to put a videoscale somewhere for example if you want to
scale the video before or after cropping.

-- 
Sebastian Dröge, Centricular Ltd - http://www.centricular.com
Expertise, Straight from the Source
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