HD branding doesn't guarantee HD quality

Just because you have an HDTV and what you're watching is advertised as being HD, doesn't mean you're watching or seeing HD video.

Not all HD is the same. For that matter, just because you have an HDTV doesn't mean you're actually watching high-definition video. A variety of factors could be conspiring to create an image that's not nearly as good as what your TV is capable of.

Make sure you're getting the most from your TV, and know what you're getting with this guide.

Wiring is important

Before anything else, make sure your HDTV is actually receiving HD signals from your home-theatre equipment.

The first step is the connection. Only HDMI and component cables can transmit HD-quality signals. Component cables consist of red, green and blue cables, plus two more for audio. It is not a yellow cable with white and red cables attached — that's a composite cable.

If you're using a yellow cable for anything other than a Wii or a VCR, you're short -changing your TV. Even the Wii looks a little better with component cables instead of the yellow composite cable. If you're unsure of what connects to where, check out this how-to guide to set up an HDTV.

HDMI cables are cheap, but cheap doesn't necessarily mean poor quality — you can pick up good-quality cables for less than AU$10. They're the best thing you can do for your TV, if you haven't already got one.

What is HD quality?

Not all HD signals are the same. Just as an HDTV isn't necessarily showing HD video, and just because something is called HD, doesn't mean it is actually true HD quality. We've mocked up some images below to demonstrate what three sources of different quality can look like. Remember, all three are 1920x1080 "full HD 1080p", but, as you can see, their quality is visibly different.

Let's take three common ways to watch a movie: DVD, online streaming and Blu-ray disc. With DVD, your DVD player or TV converts the standard-definition signal to 1080p. You're seeing 1920x1080 pixels (your TV's resolution doesn't change), but the detail is limited by the source. In this case, DVD video is only about 414,720 pixels. To account for the shortfall, your TV makes up pixels (via a process called "interpolation" or "up-scaling") to fill its 2.1-million-pixel screen. Hence, even the best up-conversion can't compete with real HD.

The first of our example pictures is a 1920x1080-pixel image, the resolution of a 1080p HDTV, but sourced from a 576p DVD. Detail is hard to see in the small versions of these pictures shown below, so please click on the images to see the full-resolution version.

Another possible way to watch an HD movie is streaming the movie via Quickflix, Sony Video Unlimited or a similar service. Even with a speedy connection, these are usually highly compressed and likely to be a 720p (1280x720-pixel) signal. Compression is a way to squeeze HD into lower data rates, making them easier and faster to transmit. The side effect is a softer, noisier image. Generally, though, it's still better than DVD, unless your internet connection slows, in which case most services will seamlessly switch to an even more highly compressed and lower-quality stream.

Here is the same image, again still 1920x1080 pixels, but simulating a compressed 720p streaming image. Note that there are other visual artefacts common with streaming (macro blocking being the most likely, where images show up as blocks of colour, pixellated, etc) not shown here; this image is just an example.

A third movie-watching option, and the best for picture quality, is a Blu-ray disc. Most Blu-ray movies offer pristine quality and highly detailed images.

What about free-to-air TV and Foxtel?

As we've discussed at length elsewhere, there's very little on free-to-air television that's broadcast in native HD or comes close to what we consider HD quality.

Under current broadcasting law, Australian networks simulcast their analog channel in SD. This ensures that those with SD-only digital TVs or set-top boxes can continue to receive the best that Australian TV networks have to offer. The unfortunate downside is that while most of this content (both local and international) is shot in HD, it's only ever shown locally in SD.

This is because commercial stations are also allowed to broadcast two additional programming streams; one in HD and one in SD. The government-backed ABC and SBS broadcasters are allowed to transmit as many streams as their budgets and spectrum allocation permit, but an HD channel is mandatory. Since the launch of One HD by the Ten Network, these HD channels have been used for alternative programs — One and 7mate primarily feature content skewed towards young males, Gem is targeted towards the fairer gender and ABC News 24 ... well, its purpose in life is pretty self-explanatory.

This is all well and good, but since the conversion of One HD from a sports channel to one showing primarily general entertainment, these stations fill most of their schedules with non-HD content, including many classic shows, such as M*A*S*H* and Get Smart — filmed in the days before high definition was even dreamed of.

To get a constant stream of live-to-air HD content, one has to sign up for a Foxtel HD package and, depending on how deep your pockets are, you can receive up to 25 channels broadcasting (primarily) content in lovely, sharp HD.

Better HD

If you've never adjusted your TV's picture settings, this is an easy way to improve the image &mdash if you do it right. Sure, you can get it close to what you want by just using your eyes, but a far better way to do it is to buy a set-up disc.

For around AU$30, one of these discs will help you perfectly dial in the exact contrast, brightness and other settings. We've reviewed a few of them in our article on Blu-ray player set-up discs for your HDTV.

All HDTVs have the potential to display amazing image quality; just make sure that you're not hamstringing your TV with incorrect installation, set-up or signals.

Via CNET