A video overlay is a technique that involves either overlaying an image or changing the common hardware chain of command, depending on the intended use of the technique. Hardware video overlay bypasses several pieces of hardware when loading a video, because this makes the loading faster and more efficient. Overlay devices are not commonly used, but they also increase the speed of video loading. Image overlays are typically added with the assistance of a graphic design program, and they are commonly used as logos, but any type of image can be added. Mid-roll video advertisements also are called video overlays, and these are advertisements that appear during the video and are commonly semi-transparent.
When a video loads, it normally goes through the central processing unit (CPU) to the graphics card and then to the computer monitor. While this method is effective, it is not the fastest way of loading a video. With a hardware video overlay, the video ignores the CPU and is loaded directly from the graphics card. The video is normally loaded in small segments to make it easier for the graphics card to handle the video's file size.
The overlay device is similar to a hardware video overlay, because it achieves a similar result, but they are different. The overlay device is connected to the graphics card and the video grid array (VGA). When the video is loaded, the overlay device injects an analog signal into the video, which speeds loading times and places much of the processing on the overlay device. While this was helpful when it first came out, graphic cards grew to the point where they could do this without an overlay device, so it is rarely used.
When someone adds an image to a video, this is known as a graphic video overlay. By using a video editing or graphic design program, an image can be added to a video file. This normally is a logo that appears in the corner, but the image can be anything the user wants it to be.
An advertisement video overlay appears when a streaming video is loading online. This type of advertisement is normally a large block with a text link in it, and it commonly appears at the bottom of the video. The graphic block is normally semi-transparent, so users can see through the block, but it also may be solid. This appears in the middle of a video, so it typically gets better exposure than some other video advertisement types.