Hi All, I am using videomixer to compose four images. 0 -- background large, all black, alpha=0.0 1,2,3 -- foreground, small, alpha=0.5 Images 2 and three are partially overlapping. The problem is that portions of image 2 and 3 that do not overlap are too dark. They look faded. Since the contribution of the background is zero, I would expect the brightness of forground images to be unchanged from original image. I wonder if there is some problem having to do with conventions regarding pre-multiplied alpha. Maybe I need to use special plugin to convert back to non-alpha colorspace. My pipeline follows. Any help greatly appreciated. Thanks much, Bert Douglas videomixer name=mix sink_0::zorder=0 sink_0::xpos=+000 sink_0::ypos=+000 sink_1::zorder=1 sink_1::xpos=+250 sink_1::ypos=-100 sink_2::zorder=2 sink_2::xpos=+100 sink_2::ypos=+200 sink_3::zorder=3 sink_3::xpos=+400 sink_3::ypos=+200 ! ffmpegcolorspace ! xvimagesink name=sink force-aspect-ratio=1 videotestsrc name=src0 pattern="black" ! video/x-raw-rgb, framerate=1/10, width=1000, height=1000 ! videobox name=box0 alpha=0.0 ! mix.sink_0 videotestsrc name=src1 pattern="smpte" ! video/x-raw-rgb, framerate=10/1, width=400, height=300 ! videobox name=box1 bottom=-200 right=-200 border-alpha=0.0 alpha=0.5 ! circle name=cir1 angle=0.0 height=200 ! mix.sink_1 videotestsrc name=src2 pattern="checkers-8" ! video/x-raw-rgb, framerate=10/1, width=400, height=300 ! videobox name=box2 bottom=-200 right=-200 border-alpha=0.0 alpha=0.5 ! circle name=cir2 angle=120.0 height=200 ! mix.sink_2 videotestsrc name=src3 pattern="snow" ! video/x-raw-rgb, framerate=10/1, width=400, height=300 ! videobox name=box3 bottom=-200 right=-200 border-alpha=0.0 alpha=0.5 ! circle name=cir3 angle=-120.0 height=200 ! mix.sink_3