The result of a blogging accident

Side-by-side video in gst-launcher

This little snippit takes video from two V4L2 sources (like webcams), and displays them side by side. The script in question is setup for 320x240 MJPEG, tweak the numbers and you get different resolution from your video sources.

One important parameter if you’re adding more sources is border-alpha. This needs to be set to 0, so that the black border that is added around a video source is transparent so you can push it on top of another video frame.

This is handy if you have two webcams, you can use this to setup side-by-side stereo display to 3D glasses. Just make sure to point your cameras at the right angle, otherwise your convergence will be all messed up.

You need the gstreamer-tools package in order to use the script.

gst-launch \
    v4l2src device=/dev/video1 ! "image/jpeg,width=320,height=240" ! jpegdec ! "video/x-raw-yuv" ! videobox right=-320 border-alpha=0 ! videomixer name=mix ! \
    ffmpegcolorspace ! xvimagesink \
    v4l2src device=/dev/video2 !  "image/jpeg,width=320,height=240" ! jpegdec ! "video/x-raw-yuv" ! videobox left=-320 ! mix.