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 platforms.
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.
cgc
Quoting marius schebella marius.schebella@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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