I am trying to crate a greenscreen application using gstreamer alpha. I am using ximagesrc to capture the window with a green background. Then I am using alpha to overlay green parts of the capture. However, I even do not know the reason, the new video seems to not playing. Is this about codecs, or is there some kind of synchronization issue between two videos?
I also included a timeoverlay and it is stuck at zero. So, the new video is not playing at all. Then I used two different patterns of videotestsrc and saw the video is playing.
My pipeline is:
gst-launch ximagesrc xname=Some\ Green\ Screen\ App ! videoscale ! video/x-raw-rgb ! timeoverlay ! decodebin2 ! alpha method=green ! videomixer name=mixer ! ffmpegcolorspace ! autovideosink videotestsrc pattern=snow ! videoscale ! video/x-raw-rgb, width=800, height=480 ! alpha ! mixer.
A playing example with no ximagesrc:
gst-launch videotestsrc ! videoscale ! video/x-raw-rgb ! timeoverlay ! alpha method=green ! videomixer name=mixer ! ffmpegcolorspace ! autovideosink videotestsrc pattern=snow ! videoscale ! video/x-raw-rgb ! alpha ! mixer.
When I used this pipeline, I expect an overlayed video, "playing". I see an output, which includes a frame of overlayed video, but it is not playing.