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DVD Video Upscaling - Important Facts

Know the Difference Between Video Upscaling and True High Definition Video


NOTE: Although this article focuses on DVD Upscaling - the same principles apply to any device (Blu-ray disc player when playing DVDs, home theater receiver, HD cable/satellite boxes, network media players, HDTVs, etc...) that may be used to upscale standard definition video signals. Just substitute the term for the appropriate component in the place of the term upscaling DVD player.

With the advent of high definition television, the development of source components to match the resolution capabilities of HDTVs are becoming more important. As a solution, most DVD players, and a growing number of other source components, and even home theater receivers, are equipped with "upscaling" capability to better match the performance of the DVD player or other source component with the capabilities of the today's HDTV's.

However, when Blu-ray was introduced, there was some confusion regarding the difference between video upscaling of standard DVD, or other standard resolution sources, and true high definition display resolution.

For an explanation of video upscaling and how it relates to true high definition video, keep on reading...

Standard DVD Resolution

In the example illustrated in this article, a standard DVD player, without upscaling, can output video resolution at 720x480 (480i). A progressive scan DVD player, without upscaling, can output 720x480 (480p - progressive scan) video signals.

480i represents an output signal that consists of 720 horizontal pixels and 480 vertical pixels. This arrangement yields 480 horizontal lines, which are, in turn, sent alternately to the display device. In other words, all the odd lines are sent followed by all the even lines.

480p represents an output signal that consists of 720 horizontal pixels and 480 vertical pixels. This arrangement yields 480 horizontal lines on the screen, which are, in turn, sent progressively, or each line sent following another.

The Upscaling Process

Upscaling is a process that mathematically matches the pixel count of the output of the DVD signal to the physical pixel count on an HDTV, which is typically 1280x720 (720p) or 1920x1080 (1080p). Depending on the upscaling DVD player (or other source device with built-in upscaling) used determines what upscaling signal output options are available. However, almost all upscaling DVD players (and other devices with built-in upscaling) now have the ability to output in 720p, 1080i, or 1080p. Then, depending on the TV, that upscaled signal can be displayed as is it comes in, or may require additional processing before the image can be displayed on the screen.

720p represents 1,280 pixels displayed across the screen horizontally and 720 pixels down the screen vertically. This arrangement yields 720 horizontal lines (or rows) on the screen, which are, in turn, displayed progressively, or each line displayed following another.

1080i represents 1,920 pixels displayed across a screen horizontally and 1,080 pixels down a screen vertically. This arrangement yields 1,080 horizontal lines (or rows), which are, in turn, displayed alternately. In other words, all the odd lines are displayed, followed by all the even lines. 1080i resolution can only displayed in its native form by High Definition CRT TVs. LCD, Plasma, and DLP TVs must reprocess any incoming 1080i signals to either 720p or 1080p for screen display.

1080p, on the other hand, represents 1,080 horizontal lines, or pixel rows, displayed sequentially. This means all lines or pixel rows are displayed during the same pass. 1080p is the highest quality HD display format that is currently in wide use.

The Practical Effect Of Upscaling

Visually, there is very little difference to the eye of the average consumer between 720p and 1080i generated signal coming from an upscaling DVD player, or other source device, once is displayed or reprocessed in order to be displayed on the screen. However, an incoming 720p or 1080p signal can result a slightly smoother-looking image, due to the fact that lines and pixels are sent to the TV in a consecutive pattern, rather than in an alternate pattern, which minimizes the processing the TV has to do to display the image on the screen.

The upscaling process, if implemented properly, can do a good job of matching the upscaled pixel output of a DVD player (or other upscaling source device) to the native pixel display resolution of an HDTV, resulting in better detail and color consistency.

However, upscaling, as it is currently implemented, cannot convert standard DVD images into true high-definition images. In fact, although upscaling works well with fixed pixel displays, such as LCD, Plasma, and DLP televisions, results are not always consistent on CRT-based high definition televisions.

Points to Remember:

1. Any DVD player can be hooked up to an HDTV. Although upscaling DVD players are better able to match the native pixel resolution of an HDTV, you will still get good results on a standard DVD player that is connected via an HDTV's provided Component or S-Video inputs (if those inputs are available on your TV).

2. If you DO have an HDTV, and a standard DVD player (without progressive scan or upscaling capability), you will get the best results using the Component video connection (red-blue-green) between the DVD player and the HDTV. In addition, if your DVD player is progressive scan capable (but does not have upscaling), always use component video outputs, with the progressive scan option enabled, when connected to an HDTV.

3. However, if you have an HDTV and Upscaling DVD player (or other upscaling-capable source device), the upscaled signal output is passed by an HDMI or DVI output connection from the DVD player to an HDTV with an HDMI or DVI input. In this case, connecting the DVD player to the HDTV using HDMI or DVI would be the best option, as this is how you would pass the upscaled signal from the DVD player (or other device) to the HDTV. Check out how to set up an Upscaling DVD Player

4. Video upscaling is only an approximation of the high definition viewing experience. To get the full impact of true high definition viewing from a disc format, you need to have either a Blu-ray or HD-DVD player connected to an HDTV via an HDMI connection and be viewing actual Blu-ray or HD-DVD disc content.

5. Another point is that all HDTVs do have their own internal scalers as well. This fact often gives way to comments that upscaling DVD players aren't needed, because an HDTV will upscale all incoming signals to its native display resolution anyway.

In response, you have to keep in mind that the scalers built into most HDTVs are usually very basic and often times do not have advanced processing to eliminate all scaling artifacts, such as jagged edges, motion adaptive noise reduction, mosquito noise, and detection of various video and film cadences. All things considered, chances are that an upscaling DVD player will have better video upscaling capability than a typical HDTV. However, there are exceptions, especially with high-end and 3D TVs. To determine how good the scaler is in a specific DVD player (or other component, such as a home theater receiver, etc...) or HDTV, several video performance test discs are available on that are worth checking out.

Of course, another way to check the difference between the scaler in an upscaling DVD player, or other component, and the scaler in an HDTV is to set the DVD player (or other component) to standard 480i or 480p and see how it looks on your HDTV. Then, set your DVD player to 720p, 1080i, or 1080p and see, again, how it looks on your HDTV. If the former looks better, then the HDTV has a better scaler than the DVD player. If the latter looks better, then the DVD player has the better scaler.

For more in-depth technical details on the video scaling process, check out the following article:

Scaling: Size Matters - Jed Deame, Home Theater Magazine

4K Upscaling

Beginning in 2012-13 there are a new breed of HDTVs and video projectors that can display 4K resolution, which is four times the resolution of the 1080p. These TVs also have the ability to upscale both standard resolution and current high definition resolutions (such as 1080p) up to 4K for screen display. For more details, read my article: 4K Resolution - Overview and Perspective.

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