[PD] pix_video alphachannel

cgc at humboldtblvd.com cgc at humboldtblvd.com
Sun Oct 26 09:39:55 CET 2003

pix_rgba will add the alpha channel if it's not already present.  I think by now
all of the capture objects in CVS should deliver a pixmap with 32bit RGBA on all

The [alpha] object enables alpha blending of GL objects, and does not affect
pix_ data. 

Apart from the misplaced alpha object, the chain below should end up with a
buffer that contains an alpha channel.  However, pix_alpha seems to be set up
for some keying functions so you probably have to supply the threshold values to
avoid completely opaque images.  

You don't say what the purpose of the patch is so I can't really advise much
further.  There are other objects that will directly do blending (pix_mix) and
keying (pix_chroma_key) without the alpha channel.  Perhaps try one of those if
they fit the bill.


Quoting marius schebella <marius.schebella at chello.at>:

> hi,
> is it possible to convert the liveinput (pix_video) to some format
> with
> alpha channel? i tried
> [pix_video]
> [alpha]
> [pix_rgba]
> [pix_alpha]
> ...
> doesnot seem to work.
> marius.
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