Video overlay is any technique used to display a video window on a computer display while bypassing the chain of CPU to graphics card to computer monitor. This is done in order to speed up the video display, and it is commonly used, for example, by TV tuner cards and early 3D graphics accelerator cards. The term is also used to describe the annotation or inclusion of interactivity on online videos, such as overlay advertising (mid-roll overlay).
Various methods to achieve video overlay are in use:
A video overlay device can be connected between the graphics card analog VGA output and the monitor's input forming a "VGA passthrough". The device modifies the VGA signal and inserts the analog video signal overlay into the picture; the rest of the screen is filled by the signal coming from the graphics card. The driver software informs the video overlay device about the desired position of the video window on screen. Because of the much greater processing power of modern graphics cards, and the awkwardness of adding additional analog hardware signal processing path, this method is now little used.
Some video overlay devices write the digital video signal directly into the graphics card's video memory or provide it to the graphics card's RAMDAC.
Hardware overlay is a technique implemented by most modern graphics cards that allows an application to write to a dedicated part of video memory, rather than to the part shared by all applications. In this way, clipping, moving and scaling of the image can be performed by the graphics hardware rather than by the CPU in software. Some solid state video recording systems now include a hardware overlay, which uses dedicated video processing hardware built into the main processor (for example the Texas Instruments DM355) to combine each frame of video with an area of memory configured as a frame buffer which is used to store the graphics.
Overlay advertising is a technique used by online video producers to monetize video content through using an overlay layer to deliver and display an ad unit. This can be in the form of a video advertisement, hypervideo a product placement or a contextual link, clickable graphic or text that provides information related to the content of the video and/or the target of the link being placed.
Videooverlay is any technique used to display a video window on a computer display while bypassing the chain of CPU to graphics card to computer monitor...
overlay in Wiktionary, the free dictionary. Overlay may refer to: Overlay network, a computer network which is built on top of another network Video overlay...
An overlay network is a computer network that is layered on top of another (logical as opposed to physical) network. The concept of overlay networking...
hardware overlay, a type of videooverlay, provides a method of rendering an image to a display screen with a dedicated memory buffer inside computer video hardware...
Timeline view consists of main video, audio, effects, videooverlay and text lines for editing. Once on the timeline video can be duplicated, split, muted...
behavior for the dots depending on the game played. Players place plastic overlays on the screen to display additional visual elements for each game, and...
into the lower base of the console. Games came with translucent color overlays to place over the screen. Optional peripherals included a pair of 3D goggles...
the SDK includes image recognition and tracking, 3D model rendering, videooverlay, location based AR. In 2017 Wikitude launched its SLAM technology (Simultaneous...
bitmap or bilevel image) and not an indexed color image. If simple videooverlay is intended through a transparent color, one palette entry is specifically...
pointer-cursor. Video pointers utilize videooverlay technology to superimpose an image of a pointer-cursor over another video stream. Video pointers may...
natively support this monochrome palette size. Alpha channels employed for videooverlay also use (conceptually) this palette. The gray level indicates the opacity...
of the videooverlay color properties for the GeForce FX series. Subsequent WHQL drivers do not handle the whole range of possible videooverlay adjustments...
localized overlay of text/graphics may be performed on the national commercial. This way, the national commercial will have a local overlay of information...
only one overlay is allowed at the hardware level. X-Video Motion Compensation Official XVideo specification, version 2.0 Official X Video Extension...
commonly used in video production and post-production. This technique is also referred to as colour keying, colour-separation overlay (CSO; primarily by...
the composite video. The RGB inputs were always active and the signal 'punches holes' in the composite video. This could be used to overlay subtitles from...
depending on graphic APIs exposed by the operating system, prohibit using a videooverlay, like a traditional multimedia player would use, with the consequence...
game, due to the use of a segmented LCD display being pre-printed with an overlay. The speed and responsiveness of the games was also limited by the time...
arcade games used full-color overlays to complement the otherwise monochrome vector images. Other uses of these overlays were very detailed drawings of...
specific video cards. One way these images can be captured is to turn off the hardware overlay. Because many computers have no hardware overlay, most programs...
machines only. 68030 only. Adds support for DSP, 16 MHz blitter and videooverlay. New v3.40 AES (last single-tasking version, but MiNT/MultiTOS-multitasking-aware)...
as a competitor to HEVC LCEVC – differential overlays that can improve performance High Efficiency Video Coding (HEVC) Family, H.265, MPEG-H Part 2 (Preliminary...
and a similar cone course was navigated easily. Guests were shown a videooverlay of the difference. Then, the cars were brought through three environmental...
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