I want to take a live video feed (say from a security camera) and overlay an image over the top of the live video. Is there hardware/software to do this realtime? I don't care about storing the data, and I can't store it to disk first, it needs to be live video in/out with overlay composited on top. Any suggestions?
Gstreamer offers the ability to overlay images on videos and has also excellent live streaming capabilities.
Some useful links:
If you are open to a hardware only solution (possibly cheaper than having a dedicated PC for the task and certainly far more reliable), then what you are looking for is a device called a logo generator/keyer.
Basically, the device constantly outputs a video of the logo you want to overlay and keys it on to the video stream being passed through. The devices range in cost from around $800 to several grand, but the low end models should be cheaper than having a dedicated computer with sufficient power to do the processing all the time if this is for more than occasional use.
there is an other nice on-the-fly video overlay software called Clamp, which is a commercial add-on for Wowza Streaming Engine. This can read overlay instructions during a live event from a text file or from database and apply them on the live stream at specified times.