I am new to GStreamer and I try to swap the color channels of a RGB-video. (e.g. red to blue). How can I do this with gst-launch?
I go trough this list but I am unable to find an element to do it: http://gstreamer.freedesktop.org/documentation/plugins.html
You can actually trick GStreamer by replacing the caps:
gst-launch-1.0 -v videotestsrc ! video/x-raw, format=RGBx ! capssetter replace=true caps="video/x-raw, format=(string)BGRx, width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive" ! videoconvert ! ximagesink
Please note that:
"width=(int)320, height=(int)240, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive"
are the default settings for videotestsrc. If you, for example, want another resolution, you need to declare it twice:
gst-launch-1.0 -v videotestsrc ! video/x-raw, format=RGBx, width=640, height=480 ! capssetter replace=true caps="video/x-raw, format=(string)BGRx, width=(int)640, height=(int)480, framerate=(fraction)30/1, multiview-mode=(string)mono, pixel-aspect-ratio=(fraction)1/1, interlace-mode=(string)progressive" ! videoconvert ! ximagesink
But of course having a dedicated element is the better solution in order to support proper dynamic caps negotiation.