Video transparent video player

Hi all,

I am newbie in kurento, I implement new video player, but video with transparent background is not working as I expected. transparent background become black.

So, how can I custom or how can config or set what params for keep the transparent backgroud.

Thanks all for help.

current code with javascript:

const filter = await pipeline.create('GStreamerFilter', {
                     command: 'glimagesink ignore-alpha=false'

expect result as below