Receivers, processors and amplifiers that perform video upscaling are common. Able to take a legacy source such as an older DVD player, VCR or other non-high definition source and convert it to near-HD quality, these receivers often perform better scaling than the television. However, there are multiple considerations and alternative options to consider before you use upscaling as an influencing feature in your next receiver/amplifier purchase.
Upscaling Definition
- Upscaling is the process by which the video output of a relatively low resolution source, such as a 480p DVD player, is upconverted to a higher apparent resolution. "Apparent" is important, since no additional picture information is added. Upscaling simply adds more lines of resolution to eliminate scan lines on CRT-based HDTVs and to bypass questionable video decoders on other types of displays.
Your TV's Role
- All modern flat-panel displays and projectors have a fixed amount of resolution. What this means is that the chips containing the individual picture elements that comprise the image are fixed in number. If you send in a video feed with less than this amount of pixels, the display must upconvert or scale the image to match accordingly. However, this does not mean that the image will look better; it simply usually means it will fill the screen. It is important to note that most TV and projector scalers are bypassed when an external source, such as a Blu-ray player or stand-alone processor, sends a video signal equal to the resolution of the display. For that reason, it is important to consider how well those external sources perform upscaling.
Stand-Alone Processors
- External set-top processors remain important, even in the age of ultra-high resolution video. The primary reason for this is mass production. Blu-ray players, gaming consoles and other HD devices are all made to perform basic scaling within the parameters of the device's price point. Stand-alone scalers are made specifically for the task of improving all video and are typically built by video-centric manufacturers. The resulting improvement over a scaler in a receiver or television may be marginal or shocking, depending on the quality of those built-in processors. Stand-alone processors also give you the option to tweak the picture quality of each source individually as it passes through. This is important, since each video device has different strengths and weaknesses in their pictures that usually require correction.
Upscaling vs Upconverting
- Upscaling in modern A/V receivers and amplifiers ranges from basic video upscaling to full-on video processing. Upconverting is a process that takes the input from a certain type of video cable, steps up the resolution to a specified level, and outputs the signal from a different type of cable. This is a very basic process on receivers employed to take the component video signals from a legacy DVD player, "upconverting" the output over HDMI. This allows one cable from the receiver to the television. Upscaling is a full analysis and correction of sharpness, color, video frame timing and other important picture quality factors as it passes through the video decoder in the receiver. Proper upscaling of legacy sources is very difficult at times to distinguish from true HD sources such as Blu-ray.
