Send the original frame and a scaled version in a single buffer?

Nicolas Dufresne nicolas at
Tue Jul 23 12:29:58 UTC 2019

Le mardi 23 juillet 2019 à 12:19 +0530, Nirbheek Chauhan a écrit :
> On Tue, Jul 23, 2019 at 1:10 AM Nicolas Dufresne <nicolas at> wrote:
> > In absence of a defacto standard, what I may suggest is to create your
> > down GstMeta, and attach the scaled down image to your original image
> > as a meta. Then all you need is a library to create the meta when
> > missing, that meta will simply ignored in elements that aren't aware of
> > it.
> > 
> To clarify, elements that passthrough the buffer like queue, tee,
> imagefreeze, etc, will (or should) leave the meta as-is, but elements
> that transform the buffer (encoders, converters, compositor, etc) may
> drop it.

If a transform was made on the buffer, I think removing the meta is the
right behaviour since the scale down would no longer match. The
proposal I made only make sense for carrying the scale down image
between the image processing elements, assuming no changes to the main
image is made other then maybe some overlays.

> Cheers,
> Nirbheek
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