How is GstVideoCropMeta supposed to be used?

[Tim-Philipp Müller]

On Sun, 2013-08-25 at 17:42 +0200, Carlos Rafael Giani wrote:

Hi,

> after looking at GstVideoCropMeta, I am confused. I found many sinks 
> inside the plugin packages that support it, only a couple of decoder 
> plugins are adding this to GstBuffers. I thought the videoparse element 
> might work by simply adding this metadata to incoming buffers, but 
> instead, it copies the pixels from within the crop rectangle.

videoparse? Did you mean the videocrop element? If yes, then the answer
is that it should use the crop meta if downstream supports that, though
it appears that that's not implemented yet.


> What would the typical use cases of GstVideoCropMeta be? Is it only 
> supposed to be used by decoders, in case their decoded frames have 
> borders or padding? Wouldn't it also be useful to remove black borders 
> from movies for example?

It could be used anywhere where downstream supports it (for raw video).

It could also be used for encoded video to signal cropping information
to decoders, e.g. from demuxer to decoder or parser to decoder.

 Cheers
  -Tim