Legend: Grey text for the novice Red text for the experienced


What is 5.1?

The term 5.1 refers to how many channels of audio there are in a particular audio stream. An audio CD for example has only two channels, so an audio CD is 2.0 – a left channel & a right channel. A 5.1 channel soundtrack, found on most DVDs, has six channels – a left channel, a right channel, a centre channel, a rear left channel, a rear right channel & finally a low frequency effects channel (LFE).

The number after the point refers to the LFE channel, otherwise known as the subwoofer. Because the LFE channel contains only low frequencies rather than the full audible spectrum it is only called point one.


What is Dolby Digital & DTS?

Dolby Digital & DTS (Digital Theatre Systems) are two different sound formats found on DVD (although DTS to a lesser extent, unfortunately). Both formats offer up to 6.1 channels of high quality surround sound but thanks to less compression DTS edges slightly ahead of Dolby Digital in terms of quality.   
 

Wait a minute… 6.1?

Yes. Selected DVDs contain Dolby Digital &/or DTS soundtracks with an additional centre rear channel – these are known as Dolby Digital EX & DTS-ES. To get the full benefit of this additional channel you need to have a 6.1 channel compatible receiver & a centre rear speaker.

To make things a little more confusing DTS has two slightly different 6.1 formats although both achieve very similar result. The first is commonly referred to as DTS-ES Matrix – it has the centre rear channel matrix encoded into the existing rear left & right channels (the same as Dolby Digital EX) – this is the same process Dolby Pro Logic uses to encode the centre channel into stereo audio streams. The second is referred to as DTS-ES Discrete – it has a totally independent (discrete) centre rear channel making it the most accurate out of all the 6.1 formats.
 

If I have a 5.1 system, can I still listen to a 6.1 soundtrack?

Yes. A 6.1 channel soundtrack is fully backwards compatible with 5.1 system. If you don’t have a 6.1 system the centre rear channel is automatically mixed into the left & right rear channels – in other words your system won’t even know it’s a 6.1 soundtrack.
 

Are there any 6.1 soundtracks available in Australia & if so, which ones? 

There are a number of DVDs in Australia with 6.1 soundtracks, unfortunately many of them are not labelled as such on the DVDs packaging or even the DVDs menu (often it’s just a pleasant surprise). Here is a list of some DVDs in Australia with 6.1 audio:
 

DVD

DD-EX

DTS-
ES M

DTS-
ES D

 

 

 

 

Austin Powers – Goldmember

Y

 

Y

Charlie & The Chocolate Factory

Y

 

 

Corpse Bride

Y

 

 

Finding Nemo

Y

Y

 

Gladiator

Y*

Y*

 

Lord Of The Rings – Fellowship Of The Ring

Y

 

 

Lord Of The Rings – Fellowship Of The Ring (Extended)

Y

 

Y

Lord Of The Rings – Return Of The King

Y

 

 

Lord Of The Rings – Return Of The King (Extended)

Y

 

Y

Lord Of The Rings – Two Towers

Y

 

 

Lord Of The Rings – Two Towers (Extended)

Y

 

Y

Master & Commander – On The Far Side Of The World

Y*

Y*

 

Monsters Inc.

Y

Y

 

Pirates Of The Caribbean

Y

Y

 

Rush Hour 2

Y

 

Y

Seven [Special Edition]

Y

 

Y

Star Wars – Episode I: Phantom Menace

Y*

 

 

Star Wars – Episode II: Attack Of The Clones

Y*

 

 

Star Wars – Episode III: Revenge Of The Sith

Y*

 

 

Star Wars – Episode IV: A New Hope

Y*

 

 

Star Wars – Episode V: Empire Strikes Back

Y*

 

 

Star Wars – Episode VI: Return Of The Jedi

Y*

 

 

Terminator 2 [Ultimate Edition]

Y

Y

 

Titanic [Collector’s Edition]

Y

 

Y

Top Gun [Collector’s Edition]

Y*

 

Y

Village

Y

Y

 

*Not auto flagged.

Here’s a list of other DVDs that aren’t officially 6.1 but feature excellent rear channel use when you set your rear centre speaker permanently on:

The Patriot (Mel Gibson)

The Dream Is Alive (IMAX)

Girl With A Pearl Earring

Twister

Saving Private Ryan


What does aspect ratio mean?

The aspect ratio is the shape that a movie or program has been shot in, the number indicates how much wider the picture is than it is high. There are two different ways to express this, one is generally used for television & the other for film – both essentially mean the same thing.

In television there are two common aspect ratios - 4:3 & 16:9. 4:3 means the image is 4 units in length & 3 units height. 16:9 means the image is 16 units in length & 9 units in height. 

In film, however, there are many different aspect ratios commonly used. Most are too difficult to express in whole numbers like 16:9 (if you were to express 2.35:1 in whole numbers it would be 47:20!). So, the aspect ratio is given as a comparison to 1. So, a 2.35:1 movie means the image is 2.35 times longer than it is high. 1.85:1 means it is 1.85 times longer than it is high.

To put this all in perspective 16:9 & 1.78:1 are essentially the same as are 4:3 & 1.33:1.
 

What does 16:9 Enhanced or Anamorphic mean?

The term ‘a picture tells a thousand words’ is spot on in this instance so I’ll let the illustration below do most of the explaining. Essentially 16:9 enhanced means more resolution for widescreen programs than was available prior to the DVD revolution (with the exception of a handful of LaserDiscs). In the illustration, which is to scale, you’ll note the difference in size of the blue area (representing a movie with a 2.35:1 aspect ratio). The blue area of the 16:9 enhanced image is much larger than the non-16:9 enhanced image. This translates into more pixels resulting in a more detailed & sharper image.

 Before the advent of DVD if you wanted to keep the widescreen aspect ratio of a film you had to shrink it down considerably to fit the 4:3 frame, which in the case of a 2.35:1 movie meant halving its size. Because the 16:9 frame is much closer to that of widescreen movies the film doesn’t need to be shrunk as much or sometimes not at all.    


Why is Widesceen better?

Nearly every movie shot in the last 50 or so years has been shot in any one of many widescreen formats, all of which are wider than a conventional 4:3 television. Until the DVD revolution when you watched a movie on VHS or broadcast television the picture was often cropped to fill the screen of a 4:3 TV – this was done by simply cutting off the sides or by a process called Pan & Scan. The Pan & Scan process involves zooming in the image & constantly moving around the part of the image you want to keep – this is done to try to keep the action in shot because simply cutting off the sides means you might accidentally chop a lead character right out of the shot! So, in answer to the question widescreen is better because you get to see the whole image the way it was shot & the way the director intended – sometimes this means seeing 50% more picture than Pan & Scan. 
 

What is HDTV?

HDTV otherwise known as just plain High Definition is a video standard of a much higher resolution than DVD, some four times more – roughly equivalent to a 35mm theatrical film print. The result is images so sharp they look as if you can reach into the TV & touch them, but that’s only real HD.

In Australia the term High Definition is used rather loosely thanks in no small part to certain political decisions made regarding HDTV broadcasts. The term High Definition can be applied to anything of 576p & above (that’s 576 x 720 pixels). 576 pixels is actually standard definition, but when the image is progressive scan instead of interlaced scan its high definition according to some. Real HD is 1080 x 1920 – if it’s any less then it’s not real HD, no matter what the manufacturers or the salesman say otherwise - so always check the resolution of a screen before you buy. There are only a handful of real HD LCD TVs in Australia & only one real HD Plasma to my knowledge (one from LG’s professional line with a price tag that will probably make you faint). Phillips & Sharp have released 1080 x 1920 LCD panels & LG have a DLP Rear Projection model. Sony has a 1080 x 1920 LCD projector but you might have to sell your car first before you buy it.     
 

What is a Frequency Response?

This refers to the range of sound frequencies that a sound recording has or that an audio component can reproduce, from the lowest frequency to the highest frequency. The human ear has a frequency response of around 20 Hz to 20,000 Hz (hertz). A CD has a frequency response very close to this – 2Hz-22,000Hz. An SACD can theoretically reach beyond 100,000Hz. 
 

What is Dynamic Range?

The dynamic range is the difference between the highest recorded sound & the lowest recorded sound. So if the lowest recorded sound in an audio recording is 20 db (decibels) & the highest recorded sound is 120 db the recording has a dynamic range of 100db.
 

What is a Sampling Rate?

This is a little difficult to explain in laymen’s terms but I liken it to motion picture film something which nearly everyone is familiar with as the technology has been around for over 100 years. A sampling rate is like a film camera’s frame-rate. While a film camera needs to shoot 24 frames per second to create the illusion of lifelike movement, digital sound on the other hand needs to record at many more frames per second to create the illusion of lifelike sound. A CD for instance has 44,100 frames per second - these frames are called samples. Most often a sampling rate is given in Hertz, so 44,100 samples per second reads as 44.1 KHz (Kilohertz).

  • Audio on a DVD-Video disc ranges from 48,000 to 96,000 samples per second (48 KHz & 96 KHz).
  • Audio on a DVD-Audio disc can reach 192,000 samples per second (192 KHz)
  • Audio on a SACD (Super Audio CD) has a whopping 2,822,400 samples per second (2.8 MHz [Megahertz]) making it the most accurate of all digital sound recordings.
     

What is an SACD? 

Super Audio CD is a high-resolution audio format developed by Sony & Phillips – it is essentially the audio equivalent of HDTV. SACD completely revolutionizes the world of digital audio by employing a new method of recording & storing digital audio known as Direct Stream Digital (DSD).

Without getting too technical DSD simplifies the way analog sound is converted into digital sound which allows it to have a much higher sampling rate than other formats, some 2.8 MHz. The result of which is the most accurate, realistic & dynamic sound you can get in the digital world. SACDs can have up to three different versions of an album on one disc – one version in DSD 2.0, one in DSD 5.1 & a third in stereo PCM 44.1 KHz (this is known as a hybrid disc & can be played in regular CD players but only in PCM 44.1 KHz). To listen to the DSD sections of an SACD you need to a have an SACD compatible player. Finally it’s worth noting that while Hybrid discs are compatible with the majority of CD players they seem to be incompatible with most regular DVD-Video players, there seems to be no official reason given for this but I’d hasten to say it’s because DVD players recognise that there is a second layer on what they only recognise to be a regular CD – this confuses the player & it spits the dummy.       
 

What is DVD-Audio?

DVD-Audio is another high-resolution audio format competing with SACD. Again it offers several versions of an album on a single disc, from 2.0 to 5.1. DVD-Audio uses an audio codec known as Meridian Lossless Packing (MLP) - a.k.a. Packed PCM.

MLP allows sampling rates from as low as 44.1 KHz to up to 96 KHz for 5.1 audio & 192 KHz for 2.0 audio – this unfortunately makes DVD-Audio a bit more complex than SACD. Because the sampling rates of DVD-Audio vary so much the audio quality can vary immensely from disc to disc. Most (but not all) DVD-Audio discs are also compatible with regular DVD-Video players, but you do need a DVD-Audio compatible player to access the high resolution part of the disc (there are some exceptions, the self titled Crowded House DVD-Audio disc has the MLP 2.0 48 Khz track in the DVD-Video area). For regular DVD player compatibility a DVD-Audio disc can also contain PCM, Dolby Digital & DTS audio.      
 

Are there any players that can play both formats?

Yes. Ever since Pioneer released the DVS-733A a few years ago many other manufacturers have jumped on the bandwagon & produced universal SACD & DVD-Audio players – these include Denon, Yamaha, Samsung & now Toshiba. Because of their support for SACD Sony & Phillips are yet to add DVD-Audio playback to their players, likewise for Panasonic & JVC because of their support for DVD-Audio are yet to add SACD playback – you can lead a horse to water but you can’t make it drink. Some of the cheaper players however are known to convert the DSD stream to PCM before converting to analog – it doesn’t make a huge difference but if you’re a purist you might be concerned. Often the tell-tail sign is an audible click or pop between tracks when playing an SACD.  My general rule of thumb is if it costs less than $500 it probably converts to PCM. There have been a number of theories put forward as to why manufacturers do this but none have really been backed up by solid evidence.  
 

HDMI?

The new buzz word of home entertainment. HDMI, or High Definition Multimedia Interface, is the first all-digital interconnecting cable for both video & audio. What this means for you is that if you have a DVD player with a HDMI connection & a TV with a HDMI connection you only need to connect one cable between them, instead of several for video & audio.

Like USB, HDMI is actually a two-way cable so devices can communicate with each other (this apparently is causing problems – components made by one manufacturer aren’t working with components made by another). HDMI also has a huge bandwidth, some 5 Gigabits per second, far surpassing that of all other consumer cables – this is enough to send two High Definition 1080p video streams simultaneously. While there is no existing technology in the world of home entertainment that requires this kind of bandwidth future technology almost certainly will – HDMI is thus future-proofed at least for a few years. That said, the 5 Gbps bandwidth could prove quite handy in the computer world today – particularly when you consider the fastest Ethernet connection is usually only one fifth of that. While HDMI has only been around for a couple of years it has already gone through several permutations. It all began with HDMI V1.0, then a year or so later V1.1 was made available, this added multi-channel DVD-Audio support & now V1.2 has been released & this adds SACD support. Trying to find out what your particular component supports can be difficult & will usually involve nagging the manufacturer over the phone. The general consensus is that when it works HDMI works great but it still has a few bugs so be warned.   

For more information check out: www.hdmi.org
 

Blu-Ray & HD-DVD

This section should always be considered a work in progress. If you were old enough to remember in the early 80s you’ll probably remember there were two competing home video formats – Betamax & VHS. Betamax was better but VHS was cheaper so VHS won & Sony, the inventor of Betamax, lost lots of money & spent a number of years with its tail between its legs (although Beta lived on in another incarnation as Betacam in the broadcast market). That’s the long & the short of it but if you thought that manufacturers had learnt something from this lesson you’d be wrong. 25 years on the battle begins again this time with competing high definition home video formats – Blu-Ray & HD-DVD. Once again manufacturers are split down the middle each unwilling to compromise which means the line has been drawn in the sand in the latest format war. Again Sony’s format Blu-Ray appears to be the better of the two but anyone who remembers the early 80s will probably know better than to put any money on it just yet.