Video scaler

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A video scaler is a processing device for converting video signals between arbitrary resolutions. They are usually used for converting low resolution interlaced signals (such as composite video or S-video) to higher resolution non-interlaced like HDTV, although they can also work in the reverse. It performs a similar job to a Line doubler however with extra signal processing and optimizing.

These devices are available for both digital and analogue inputs and outputs or, more commonly, both combined and are usually combined with other video hardware. A prime example are devices for converting an analogue VGA signal from a computer into DVI (digital) signal for display on a monitor; in this case the resolution outputted by the computer may be lower than that required by the monitor creating a distorted image. A scaler can be used to increase the resolution to the correct level.^[1]

1 Interlacing
2 Footnotes
3 References
4 External links

[edit] Interlacing

for more information on this topic see interlace

Interlacing is a process used mostly television and video signals to improve picture quality without increasing bandwidth. It is form of scan that only renders alternate lines of a displayed frame. With the next frame the opposite set of lines (e.g. those not rendered on the previous frame) are scanned.

Although this increases the resolution of the image it degrades the quality, a video scaler is able to deinterlace a signal and increase the reolution with only minor affect on the quality.

In the consumer market, a frequent application for these devices is converting low-resolution video into high-definition (for example, 480i to 1080i), by inserting the scaler in the video chain between a low-resolutioin video source (ex. VCR) and a higher resolution display (ex.TV). Depending on the quality of electronics, the viewer may perceive an improvement in video quality even though the amount of video information remains the same throughout this process. All TV stations which broadcast in high definition use commercial-grade scalers as part of their infrastructure to enable transmission of legacy standard definition video material on a high definition signal.

A rare use of the term "HD upconverter" applies to the upconverting DVD player. This type of DVD player converts DVD-Video format video on a DVD directly to a high definition video signal for use with an HDTV. An upconverting DVD player effectively has a simple video scaler built in that is limited to accepting input from the player's video transport and not from any external sources. Such a DVD player may be constrained by digital rights management HDCP which limit upconversion to being output only on copy-protected digital transports or with lower resolution output. Conceptually upconversion can be done with analog outputs as well.