[GEM-dev] 0.90 and pix_video under Linux

[IOhannes m zmoelnig]

Mirko Petrovich wrote:
> Hi IOhannes,
> 
> Thanks for your reply, but I'm not having any luck.
> 
> IOhannes m zmoelnig wrote:
> 
>>
>> > Alpha blending doesn't work with pix_video using [alpha] and
>> > [colorRGB]in the renderchain (it worked in 0.888-cvs).Should I use
>> > [pix_alpha] instead ?
>>
>> hmm. i just tried and it certainly works for me.
>> does it produce any result (e.g.: image dimming but no transparency) ? 
> 
> 
> Nothing but black.

probably your [color]/[colorRGB] is set to black ? (or the alpha-channel 
  is 0 ??)
thinking of this, it might be, that the video4linux-driver is able to 
produce RGBA-images but unfortunately sets the alpha-channel of each 
pixel to 0. in this case, you will have to raise it manually.

> My idea was filling buffers on the fly, and selecting from differents 
> sources (pix_video, pix_film, pix-mixers), so I guess I will have to 
> send a flag to activate pix_flip depending on the source.

probably yes

> 
> I don't understand this solution, do you mean rewriting in cpp or just 
> the patches ?

unfortunately C++

>>
>> and (if you want to zoom in a videoIN-image) you could do some tricks 
>> with offset/dimen-messages to the [pix_video]-object 
> 
> I will try this, at least for video-IN.

but again you will get images of different dimensions.


if the whole thing is just about fading several streams, use 
openGL-alpha blending instead of [pix_mix], so you don't have to care 
about dimensions at all (so the only remaining issue would be, setting 
the alpha-value of the [pix_video] to a decent value)



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IOhannes