High Definition Overview

by Philip Sawyer

This is intended to be a simple overview of the new high definition video formats. I've omitted or skimmed over a few details in order to keep it clear. If some of the jargon is new to you, there are other articles about DVD and PAL/NTSC video in our articles section, and there are many other sites on the internet with further details. A good source of information about DVD is Jim Taylor's Internet DVD FAQ, which is available on numerous websites.


For years we have been watching TV in analogue. TV waves sent from a transmitter are picked up using an aerial connected to your TV. These waves are decoded by the TV and transformed into hundreds of lines of information which go together to make up a TV image.

In recent years TV stations have also been broadcasting in digital. The advantage of digital is that if you get the signal, you get a clean signal without ghosting or interference lines, and it is therefore clearer and sharper. But standard definition digital still uses the same 576 lines of resolution as analogue.

TV stations are also broadcasting some programmes in High Definition (HD), which has more lines of resolution than analogue or SD broadcasts. HD can have up to 1080 lines compared to the 576 lines in PAL systems and the 480 lines in NTSC systems. This makes for a much clearer and more detailed picture on your TV display.

When DVD was introduced high definition TV was in its infancy and the storage capacity of discs was limited. So what we ended up with was a product that represented a significant improvement over VHS, but that was still limited by the resolution of the image and the amount of compression required to fit the material onto a DVD disc.

Since that time, larger capacity discs have been developed. Compared to the 700Mb capacity of a CD and the 4.35Gb capacity of a single-layer DVD, a HD disc can store up to 25Gb on a single layer. This additional capacity is required to store the large amounts of data that HD video requires. It also means that the video does not have to be as compressed as on DVD, which significantly reduces artefacting.

So what HD formats are available?

Unfortunately, due to politics and stubbornness on the part of the manufacturers we have ended up with two competing HD formats. Toshiba, Microsoft and the DVD Forum backed HD DVD, while Sony came up with Blu-ray Disc (BD for short). These are incompatible with one another and neither can be played on a conventional DVD player. Both formats were released worldwide in 2006 and have made small inroads into the market, though neither threatens DVD at this stage. Blu-ray hit our shores in mid-2006, while HD DVD came towards the end of the year, with the first player being available early in 2007.

HD DVD has a capacity of 15Gb on a single-layer or 30Gb on a dual-layer disc. There is talk of a triple-layer 51Gb disc, but it remains to be seen whether this ever reaches the marketplace.

BD has a capacity of 25Gb on single-layer or 50Gb on dual-layer discs.

HD also introduces a new video standard of 1080 lines, which is the same in all countries and replaces both PAL and NTSC. It's the same number of lines as in a true HD TV broadcast. So theoretically a disc released in one country would be playable on machines in all other countries. At the moment this is the case with all HD DVD and BD releases (ignoring the issue of region coding). However there is an exception in that the refresh rate of HD TV broadcasts in PAL countries is generally 50Hz, while in NTSC countries it is generally 60Hz. If a HD TV broadcast was released say in Australia in a 50Hz transfer, it might not be playable in the USA where the standard is 60Hz. It is more likely that both refresh rates would be playable in Australia where we are used to having multiformat TVs and DVD players.

The good news is that so far all HD releases have been 60Hz. Aside from the standardisation of format, this removes the 4% speed-up that film transfers have suffered from ever since the PAL standard was adopted. You will be able to see movies at the correct speed and with the voices at the correct pitch as they were intended (most people brought up on PAL don't notice the effect).  The speed-up effect is due to film speed of 24 frames per second (fps) being increased to the 25 fps of PAL video. Actually PAL is 50 half-frames per second, and each frame is interlaced - each whole frame is made up of two frames, the first of which has the odd numbered lines and the second the even numbered. While this has a positive impact in that it reduces the bandwidth required for PAL video, it leads to interlacing artefacts (see our Artefacts Guide for examples). HD video can be 1080i - the i stands for Interlaced - which is the standard of HD TV broadcasts in Australia, or 1080p - the p stands for Progressive, which is a different method for displaying images.  Progressive scan displays the scan lines sequentially, eliminating interlacing artefacts, and actually results in a more detailed picture.

Because of the increased storage capacity of the new discs, video does not have to be compressed as much as it is on SD DVD.  Most BD titles so far have been authored using the MPEG-2 codec, which is the same codec used for SD DVD, using a higher bit rate than SD DVD is capable of. Most HD DVDs and some BDs have been authored using the newer VC-1 codec, which achieves better results.

Due to the bandwidth required to carry a HD signal, you can only get the full HD experience through HDMI or component connections. Other connections will result in the video being downconverted to a lower resolution.

Both systems also introduce some new audio formats. Dolby Digital Plus (DD+) is a compressed format with a resolution equivalent to DTS audio, but capable of up to 7.1 channels. Dolby TrueHD and DTS HD Master Audio (DTS HD MA) are both lossless formats, and can have the same resolution as the virtually defunct DVD-Audio, again in up to 7.1 channels. Linear PCM is also capable of 7.1 channels, compared to the 2.0 maximum on DVD.

The drawback of the new audio formats is that not everyone will be able to take advantage of them right away. There are currently no receivers on the market that will decode the new formats. In the meantime, if you connect the player to your receiver using the digital outs, you will have to configure the player to output a PCM signal. DD+ does work through the digital outs, but receivers decode it as DTS. Some players will decode TrueHD and output it and DD+ through the 5.1 analogue outputs in full resolution, but at present no player has decoding for DTS HD MA. If you can connect your player to your receiver using a HDMI cable, you can get both DD+ and TrueHD in their full resolution as well.

One of the bugbears of DVD was the region coding of discs and the locking of machines to a single region. The news on the HD front is mixed. At the moment there is no region coding for HD DVD. BD has three regions instead of the six regions for DVD. Australia is in Region B, which also includes Europe. The USA and Japan are in Region A, while countries like China and Russia are in Region C.

This would seem to be an advantage for HD DVD, but there remains a possibility that HD DVD will introduce region coding at some point in the future.

Another drawback of the format war is that while some studios are releasing discs in both formats, others are committed to one format only. Fox, Disney and studios owned by Sony are releasing only in the BD format, while Universal and Studio Canal are committed to HD DVD only.

What other changes are there?

- If you have a widescreen display, you may have noticed that in order to get a 16x9 enhanced picture to fill the screen you have to switch to "full" mode, otherwise the picture appears squeezed. Some displays do this automatically for you. This squeezing happens because analogue and SD video is a 4x3 format. HD on the other hand is a 16x9 format, so it fills the screen automatically.

- HD discs won't play on existing DVD players, so you have to get a new player to take advantage of the new formats. Some companies are releasing HD DVDs in what they call "combo discs", which is a disc with the HD DVD version on one side of the disc and an SD DVD version on the other. This means that you can buy a movie and watch it on your current DVD player, and when you eventually buy a HD DVD player you don't need to buy the disc again, just turn it over.

- Menus in HD DVD are different from those in DVD, in that you can bring up the menu while the feature is playing. On DVD the feature stops playing when you go to the menu.

- Some discs, mainly from Warner, have what is called the In Movie Experience (IME). This is an interactive extra sort of like an enhanced commentary track, which you can switch on and off during playback. It can feature a picture-in-picture of the director or other crew or cast talking you through a sequence, and other material such as diagrams and pop-ups. I have not seen one of these yet so I can't comment on how worthwhile it is. I have heard though that this feature isn't able to be implemented on BD discs, so Warner are not releasing the titles with IME on BD.

- The case for both formats is smaller and thinner than DVD cases, with rounded corners. They look alike but can be told apart by the logo at the top of the case, and the red for HD DVD or (naturally) blue for BD case colour.

- Image Constraint Token (ICT).  Both HD formats support a digital rights management feature called the Image Constraint Token (ICT). The good news about ICT is that it hasn't been implemented on any titles yet, and may not be for at least three years. The bad news is that ICT will stop you viewing a HD movie in HD unless you have a secure digital connection between your player and your display device. Basically, if switched on the ICT would only allow HD pictures to be shown on a device connected using HDMI version 1.3. That is, you would need to use a HDMI cable to connect a player with a HDMI v1.3 connection to a display with a HDMI v1.3 connection. Any other connection will result in the picture being downscaled to SD DVD quality.

The reason this hasn't been implemented is that there simply aren't many HDMI v1.3 devices out there at the moment. So the studios have agreed not to implement ICT until 2010 at the earliest. If they do implement it, you would need to upgrade your equipment in order to watch HD movies. So it's not a good thing for consumers.


There are two BD players and one HD DVD player available in Australia at the time of writing.

The BD players come from Samsung and Panasonic, and both are expensive, with the former around $1699 and the latter $2749. These are the recommended retail prices, and you can expect to pay less at a retailer. The Samsung has received less than glowing reports due to firmware issues, though the company's website states that these issues have been resolved. Upcoming in March is Sony's PS3 gaming machine, which will also play BD discs.

The only HD DVD player available at the moment is the Toshiba HD-E1 which has an RRP of $1099. This player does not have multichannel analogue outputs, so if you don't have a HDMI input on your receiver you might want to wait for the more expensive HD-XE1 which will be released here shortly at about $1600 RRP. The HD-E1 will upscale all SD DVDs to 1080i through HDMI and will also do this via a component connection if the DVD is not copy-protected.  However the maximum resolution of the HD-E1 is 1080i.  The HD-XE1 will output at 1080p, has 5.1 analogue audio outputs and will also have a HDMI v1.3 connection.

There is some region coding silliness at work with all of these players. Both BD players are region locked for BD discs to Region B. I understand that the Samsung is region-locked for SD DVD to Region 4, but apparently it can be unlocked using remote codes. The Panasonic is reportedly not region-locked for SD DVD.

The Toshiba has no region-coding for HD DVD but is region-locked for SD DVD.

It seems there is no perfect solution to this state of affairs at this time, though it is to be hoped that there will be region-free players for both formats at some time in the future.

Two companies are working towards making the format war obsolete in terms of players, and reducing the confusion in the mind of the consumer. LG have announced a dual-format player that will play both HD DVD and BD discs. Warners have announced TotalHD, which is a two-sided disc with the same content in HD DVD format on one side and BD format on the other, which they expect to start using late in 2007.

Who is going to win this format war?

If I was to bet on anyone at the moment, it would be... SD DVD. Seriously, no clear winner has emerged yet. Each format has gained a toe-hold in the market, but neither has any real competitive advantage over the other, because the numbers of players and discs sold so far is miniscule compared to DVD. The BD camp in particular have already issued numerous press releases claiming victory in the format war, based on little more than wishful thinking at this stage.

In BD's favour there are more software titles available or announced for future release, while the upcoming PS3 will play the new format out of the box. But HD DVD has been in the marketplace longer, has no region coding and the players have been much cheaper than their BD counterparts. HD DVDs can also be played on an Xbox 360 using an optional add-on, available in Australia at the end of March for around $250.

The additional storage capacity of BD may also seem to be an advantage, but reports are that titles released on both formats and authored using the same codecs look and sound identical on each format.

It seems conceivable that both formats will be around for years.  Where previous new formats have been winners in quality or convenience or both over their predecessors (CD over LP, DVD over VHS and so on), neither of these new formats will grab the attention of the public at large, who seem content with DVD as it is.  Over time the availability of cheap software and hardware for either format may decide the outcome of this war one way or the other, but it won't happen overnight.

Is it worth buying into HD, or is this just another way for the manufacturers and studios to squeeze more money out of the consumer?

The answer is probably both.  I own a HD DVD player, and can report that when using it with my projector there are significant and easily noticeable differences between HD DVD titles and their SD equivalents.  The picture has more detail and colour fidelity is improved.  There are few artefacts, with edge enhancement, aliasing and Gibb Effect being completely absent from almost all titles I have seen. The higher resolution of the audio is also impressive, having eliminated the digital edge that compression causes on SD DVD transfers. Of course all this depends on how well the content is transferred, and what condition the originals are in. But at its best HD can take your breath away, and you can forget that you are watching a video transfer, which is what home cinema should be all about.

7th February 2007