user6002: 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?

user2703: 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.

user3295: Gstreamer offers the ability to overlay images on videos and has also excellent live streaming capabilities.
Some useful links:
https://coaxion.net/blog/2013/10/streaming-gstreamer-pipelines-via-http/
https://developer.ridgerun.com/wiki/index.php/Fast_GStreamer_overlay_element#Picture_overlay_examples

user2836: 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.

6002: <p>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?</p>
 2703: <p>there is an other nice on-the-fly <a href="https://wowzatoolbox.com/clamp" rel="nofollow">video overlay software called Clamp</a>, 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.</p>
 3295: <p>Gstreamer offers the ability to overlay images on videos and has also excellent live streaming capabilities.</p>

<p>Some useful links:</p>

<p><a href="https://coaxion.net/blog/2013/10/streaming-gstreamer-pipelines-via-http/" rel="nofollow">https://coaxion.net/blog/2013/10/streaming-gstreamer-pipelines-via-http/</a></p>

<p><a href="https://developer.ridgerun.com/wiki/index.php/Fast_GStreamer_overlay_element#Picture_overlay_examples" rel="nofollow">https://developer.ridgerun.com/wiki/index.php/Fast_GStreamer_overlay_element#Picture_overlay_examples</a></p>
 2836: <p>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 <a href="http://www.bhphotovideo.com/c/buy/Logo-Generators-Accessories/ci/8295/N/4028759389" rel="nofollow">logo generator/keyer</a>.  </p>

<p>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.</p>
