Digital TV Comparison

One very big question on consumers minds at present is how good will the TV picture be on their new “HDTV Capable TV”. Sadly there is no simple answer. Over the course of this article we hope to provide you with some idea of what to expect, so read on for OpenMedia’s guide on what to expect from your TV and the soon to be launched New Zealand Digital TV network.

What TV is Available Today ?

At present in New Zealand you are likely to get your television from one of the following sources

  • Free To Air Analogue Terrestrial TV via your Aerial
  • Sky UHF Analogue Pay TV via your Aerial
  • Sky Digital Pay TV via a Satellite Dish
  • Telstra Clear Digital Cable TV
  • Free To Air Digital Satellite TV off Optus B1

What’s “Coming Soon” ?

Of the currently available options very few consumers currently watch “Free To Air Digital Satellite TV off Optus B1″. This will shortly change when the new FreeView digital network launches in 2007 offering the following additional options

For the moment it appears that these two new options will still be transmitting SDTV (standard definition TV). There are currently no official plans to offer HDTV in New Zealand until SkyTV launches its HDTV service. The Sky service isn’t expected to arrive until 2008.

How Good Will They Look ?

So for now we are all either stuck with Analogue TV, or SDTV. None of these formats will make full use of your new “HDTV Ready” screen, but we will attempt to show you just how well a myPVR unit can cope with these various formats. One thing to note is the images are exact digital copies of the output from a myPVR unit, and may not represent how the image will look on your screen. They are provided as a comparison of the various formats.

If you don’t understand the differences between Standard Definition TV, 720p and 1080i take a look at the Wikipedia Resolution Chart.

Analogue 4:3 TV Picture

Normal PAL analogue TV has an effective digital resolution of 720×576 pixels in an aspect ration of 4:3. The samples below were taken from a recent broadcast of One News off TV1 over a normal Analogue TV. Note that we have preserved the original aspect ratio of the video which results in the large black borders down the left and right hand sides when displayed on wide-screen TVs.

Analogue 4:3 on a Normal TV Analogue 4:3 up scaled to 720p Analogue 4:3 up scaled to 1080i
4:3 Analogue Normal TV 4:3 Analogue 720p TV 4:3 Analogue 1080i TV

You might ask why we don’t include a SkyTV signal. At present SkyTV SetTop boxes only support analogue connections, hence picture quality will be comparable to the screen shots above, or perhaps a little softer with less ghosting. The 4:3 picture looks a little odd as we haven’t stretched the image to 4:3, the image is stretched automatically by your TV screen.

Digital 4:3 FreeView SDTV Signal

This is the same edition of “One News” but captured off the new FreeView digital network. At present TV One and TV 2 only transmit in 4:3. You will notice it has a much clearer picture, and scales far better on 720p and 1080i displays. The resolution of the 4:3 digital signal is 720×576 which is equivalent to a 4:3 DVD.

Digital 4:3 on a Normal TV Digital 4:3 up scaled to 720p Digital 4:3 up scaled to 1080i
4:3 Digital Normal TV 4:3 Digital 720p TV 4:3 Digital 1080i TV

Some comments

  • The digital picture is far clearer as your get none of the ghosting or other distortion your normally get over a TV aerial.
  • The same picture quality should be possible should you go with Terrestrial or Satellite based Digital TV.
  • In order to get this sort of picture quality you will need either a myPVR unit, or a SetTop box that supports a DVI or HDMI connectivity.
  • Most of the standard FreeView set top boxes will only have Composite and SVideo connections which provide a much lower video quality
  • You can choose to stretch or modify the 4:3 picture to remove the back borders on a wide-screen TV but this will normally result in picture cropping or distortion.

Digital 16:9 FreeView SDTV Signal

There is currently a 16:9 wide-screen test channel on the new FreeView digital network. This channel has an effective resolution of 1024×576 which is equivalent to a wide-screen DVD.

Digital 16:9 on a Normal TV Digital 16:9 up scaled to 720p Digital 16:9 up scaled to 1080i
16:9 Normal TV 16:9 720p TV 16:9 1080i TV
16:9 Normal TV 16:9 720p TV 16:9 1080i TV

A couple of comments

  • The small black borders down the sides of the 16:9 images are present in the original video, and would normall be hidden in the edges of your TV.
  • The video scales very well to both 720p and 1080i displays thanks to the clean wide-screen digital feed.
  • The up scaled images use the myPVR upscaler to produce a superior quality picture.
  • Until we get a true HDTV signal this is likely to be the best picture you can get from your “HDTV Capable” screen from a TV signal.
  • Existing standard SkyTV Set Top boxes cannot drive your screen over DVI or HDMI so you it is unlikely you can get this sort of picture quality off their hardware.
  • When SkyTV launch their HDTV system it will require new set-top boxes. At present we don’t know what sort of digital connectivity they will offer, but it likely to be HDMI. We understand that they will be enabling HDCP to prevent copying of the HDTV signal.

In Summary

The new “FreeView” New Zealand Digital TV network is likely to offer a far better picture for your HDTV screen than existing sources as long as the channels decide to transmit in wide-screen. In order to best make use of your TV you will need a set-top box that is capable of digital output over VGA, DVI or HDMI. If you use a more conventional Composite of SVideo cable there will be a dramatic difference in quality.

References

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Article originally published Monday, 09 October 2006