What is HDTV?
A quick introduction
HDTV, or High Definition TeleVision
, is the latest revolution in broadcasting. For ever so long now we have been viewing pictures that are 576 pixels in height (and around 720 wide), interlaced at fifty half-frames per second (that's 480 pixels in height at sixty half-frames for NTSC, but we won't be discussing NTSC much here). We had 'widescreen', but this wasn't true widescreen, this was simply outputting a stretched picture which would be put back into the correct shape by the television - ironically the expanded width is the resolution that was not of a 'better' quality.
Now? Now enter HDTV.
HDTV, on the other hand, promises four times
the quality of your existing picture. It is, essentially, as revolutionary a change as was the introduction of colour.
HDTV comes in two forms - 720p and 1080i. This means that, using progressive scan, it offers 720 pixels height (that's 1.25× better) and 1080 pixels height interlaced (that's 1.875× better).
There is a progressive 1080 resolution, but this is expensive due to a really large bandwidth and processing to refresh 1080×1920 pixels (or two million pixels) fifty times per second, or 103,680,000 pixels updates per second for "Full HD".
By contrast, a normal old low-res PAL TV does half of 576×720 fifty times a second, which is a full update of 10,368,000 pixels per second.
I am making the assumption that the quoted resolution is what you see, as I'd expect the sync to be separate from the picture information. This is not true for PAL broadcasts, which are actually 625 lines in height, however the part that you see is only 576 lines because the rest is used for sync and teletext (both of which are now largely historical).
The world ummed and awwed when television went colour. This, the change to High Definition, is about the same magnitude.
But why isn't the world scrambling to get new televisions? The principal problem is that HD is not compatible. The BBC could broadcast in colour right away, as by a miracle of engineering it was perfectly okay. If you have a black and white telly you saw black and white. If you had a colour telly, you got the exact same thing in colour.
Not so with HD. You need a new set-top-box to receive HD, you need a new television to watch HD, and when I first wrote this in the beginning of 2007 there was no commercially available DVD recorder or video recorder that is HD capable; I think there is a BluRay recorder now, hardly a wide choice of equipment...
Add to that, there are precious few HD channels available. The only Astra2/Eurobird freebie is BBC HD (and Channel 4 HD is on the way). The others are part of SkyDigital who apparently seem to take the opinion that for a better signal you can pay a little bit more. HD-DVD and BluRay have yet to make a big impact on the marketplace. The HDMI outputs on 'regular' DVD players effectively upscale the standard DVD image. It should work well for good quality DVDs with a high bitrate, but there's no getting around the fact that it is not originally a high resolution disc.
I have a DivX capable DVD player, but sadly it tells me it cannot play HD-DivX. This is a shame, because if it could down-convert HD-DivX to something suitable for a regular TV (it isn't an HD unit), this might help encourage people to make use of this format - especially considering HD video cameras (which 'record' onto an SD card) are entering the domestic market.
The HD revolution is here, and it is starting. It just isn't doing it very quickly!
I would imagine if BBC did shadow services of BBC1 London, BBC2, BBC THREE, and BBC Four, along with some ITV shadow services - all in HD alongside the existing 'standard definition' service that we are using right now, then acceptance of HD would accelerate... assuming that the broadcast was true HD and not just PAL upscaled. For example, on a news report about HD on the BBC six o'clock news (beginning of March 2007), the presenter mentioned that the programme was recorded and broadcast in standard definition, so PAL viewers and HD viewers would see the exact same thing.
It's a bit of a catch-22. They won't want to commit to that sort of expense until there are enough viewers to make it worthwhile, and the viewers won't want to commit to the expense of all-new equipment until there is enough programming to make it worthwhile.
Interlaced? Progressive scan? What?
Your regular television uses interlacing
to draw the pictures that you watch. Any book on television theory will tell you that PAL and SÉCAM update the screen at 25 frames
per second (30fps for NTSC). The problem is that this could lead to flicker, such as that which some of the more flicker-susceptible people (myself included) may see on certain cinema screens.
The simple answer, double the refresh rate. Scan the screen 50 times a second (60 for NTSC). Problem is, that would require a huge
chunk of bandwidth for each television station.
In order to "keep it real", the broadcasters (remember, this was back in the black-and-white days) came up with a very ingenious solution. Essentially every frame is split into two fields
, which - for arguments sake - we shall think of as "all the even lines" and "all the odd lines".
An interlaced picture is therefore built up by displaying all of the odd lines in the picture, and then we whizz back to the top and fill in all of the even lines. You can see this in the picture on the right, which was incidentally of receptionist Alice (played by Sam Grey) in the BBC television series Casualty
, she now wears a blue uniform having taken a career change.
There is a potential 'jitter' factor between frames for fast moving subjects with a very fast shutter, however the television screen itself, along with the human eye, will generally blend these small differences so they are not noticable. After all, we've been living with interlaced television for over half a century and I've not yet
heard somebody say their football game was ruined by inter-field displacement!
scanning, on the other hand, works like a computer monitor. The picture is built line by line, top to bottom. While it may still update 50 times per second, it will be updating a complete
screen each time, not half the screen. This will lead to a higher quality, but as we're only looking at around 720 lines (height) resolution, it probably won't look that unlike a normal TV picture, only clearer and sharper.
Anybody who has watched a DVD on their computer will, no doubt, be aware of the differences between that and a regular television, though please note
that you cannot compare the two if you use composite video or UHF into the TV (worst case - composite to a VCR then UHF to the TV) because only RGB passes the colour and sync separately. Composite, S-Video, and the worst offender of all UHF (which is why most DVD players do not
have a UHF output) cause a loss of visual quality basically due to squeezing the display information down one wire, and in the case of UHF, you are modulating the signal onto an RF carrier (like a mini-transmitter) only to demodulate it again after a few feet of cable. I have
to do this, my TV only offers UHF input, however if your TV has something such as SCART, even composite video is a heck of an improvement over UHF!
The two HDTV resolutions
The high-definition part of the HD specification is, really, catered for by the 1080i part. This will allow you to see 1080 lines (height), which is effectively twice the vertical resolution of a standard picture. If we then make an assumption that the horizontal quality is also twice as good, then simple maths will explain the adverts claiming HD is four times better quality than normal TV. I'm not sure I'd agree, but whatever, the definition offered by HD will leave normal TV looking somewhat lame.
Unfortunately, the mechanics of updating a screen with that much information are - as you may expect - very complicated. This is why the 1080 resolution is (usually) interlaced. But, don't let that put you off. I'm sure many of you reading didn't know your (PAL) picture is interlaced until just now... ☺
The other part of the HD specification is for a progressively-scanned picture of 720 pixel height. I would imagine the television would switch between the two as necessary.
Here is a faked comparison. I have taken a scan of a rather nice lawnmower (a Countex X-series) and fiddled it to show you the relative difference between normal television and the two forms of HD. This should not be taken as anything other than a simple comparison in relative quality.
Only a slight reduction, better than normal TV!
What you're probably watching now!
Horribly low-res, no wonder USA and Japan launched HD!
To put this into numbers:
In comparison, NTSC offers a mere 345,600 pixels (seriously! 480×720).
Standard TV (PAL) HDTV
Resolution 576 (vertical) 720 or 1080 (vertical)
720 (horizontal) 1280 or 1920 (horizontal)
414,720 pixels 921,600 or 2,073,600 pixels (wow!)
Format 4:3 / 4:3L / 16:9(ana) 16:9
Audio Mono or stereo 5.1 Dolby Digital
Who is using HDTV
It is sad to say, but the Brits are somewhat behind the times. HD transmissions in America began in 1999. At the end of 2006, around 10% of the population had the capability to view HDTV with around 25 channels completely or partially broadcasting in HD; which is interesting given that the transmission format, MPEG4.H264, didn't arrive until the end of 2002! Perhaps the American rollout was the initial testbed of the HD system?
In Japan there are 10 channels which have broadcast in HD since late 2003, to approximately 15% of the population. The national broadcaster, NHK, now creates 90% of its programming directly in HD (oh no, you'll be able to see every single bug in Takashi's Castle! ☺ ).
Here in Europe, it is the Germans in the lead. Two channels (SAT1 HD and ProSieben HD) were launched on the 26th of October 2005. Both of the channels are broadcast 'in the clear', with others following.
Other European countries are beginning to implement HD (it is being rolled out in France now) but it seems a number of HD channels are part of subscription-based services such as Canal+.
In the United Kingdom, it was the BBC which launched HDTV. It is my understanding that Sky wanted HD in place for the World Cup, however for some reason or other things didn't quite come together in time. Now Sky has a number of HD versions of its channels - Sky One, two movie channels, two sport channels, one of the box office channels, and a small number of additional channels (such as Artsworld).
But the BBC was there first, with channel 145 in the EPG. This, BBC HD, shows a selection of programmes from the BBC channels in HD, often as a simulcast of the SD version - programmes such as "Dr. Who", the 2008 "Eurovision Song Contest", various "Euro2008" matches... (check RadioTimes or equivalent for listings)
What MPEG4.H264 offers
Unveiled at the end of 2002, the H264 codec used in conjuction with MPEG4 supposedly brings into effect an evolution of the MPEG2 standard which has been in use for over 15 years.
The main advantage of the codec is that it uses less than half the bandwidth required by MPEG2, and keep in mind that we are talking about an HD signal too!
While some people can see MPEG "artefacts" in an MPEG2 signal (try oMusic
, Zone Horror
, or some of the freebie channels when the picture is moving rapidly - if you pay attention you'll see it goes "blocky"), the jury is still out on MPEG4.H264. I think the reality is that as technology advances, broadcasters will try to fit an "adequate" signal into less and less bandwidth. The only thing that will change is the definition of adequate, which will be a balance between pleasing the public and being able to make more money by outputting more channels.
A DVD-quality signal broadcast in MPEG2 requires 5.37 Mbit/sec. Typical freebie channels appear to use in the order of 2 Mbit/sec (and you can tell). MPEG4.H264 is supposed to be able to do the exact same thing with a bandwidth of only 944 kbit/sec, that's over 5 times less.
It is worth noting that the actual benchmark is ~1Mit/sec for a standard quality (PAL) signal, not an HD signal as is frequently quoted.
You can see the obvious attraction - a typical transponder running at 27.5Mbaud may be able to output around seven 'normal' channels in MPEG2. If we use MPEG2 for HD, this falls to one or two channels. By using MPEG4.H264, around five or so channels can be offered, at the much greater resolution, on the same transponder.
It is interesting to note that while the various HD channels are present in the Sky EPG, you will only see a message asking you to call a number for details of how to receive the HD channel. This is because the channels are transmitted using a different "codec". A "codec" is a thing inside the decoder that translates the data into a picture. Built into the standard Digibox is the MPEG2 codec. To receive HD signals, you require an MPEG4.H264 codec.
Or, to put it in simpler terms, the standard Digibox speaks English (MPEG2) and in order to receive HD, the receiver would need to speak both English and Italian (MPEG2 & MPEG4)...
It is not possible to retrofit MPEG4 into an older Digibox. This is because even if we could, somehow, get the receiver upgraded to decode HD signals... the very best we can hope for is a standard definition output. The Digibox outputs UHF, composite video, and RGB. All in Standard Definition. There is no digital output. There would be little actual benefit to having HD built into a standard Digibox, it would only allow access to HD content. It would not provide HD quality, the PAL-capable hardware is simply not up to it. But, then, neither is the video decoding hardware, so let's quit while we're ahead, yes?
What you will require, exactly...
You will need a new digital receiver that supports the MPEG4 protocol (this web site is concerned with satellite transmission, however HD is expected to be rolled out terrestrially as well).
You will also need a new television. Be aware that the label "HD Ready
" only assures you that the television will be capable of 1280×720 (the 720p version). The maximum possible resolution attainable is 1920×1080, which simply cannot be realised if your display has a lower resolution than this! Some HD sets may actually have a resolution as low as 576×480. Okay, you'll be able to see
HD broadcasts but there'll be no gain for you.
Those televisions which support the complete HD specification should be marked "Full HD
HD televisions will have analogue component input (often marked YpbPr
), perhaps S-video and/or RGB, and a digital input DVI
Note, however, that if you wish to view a copy-protected HD programme, you will need to have support a digital input capable of supporting HDCP
. This should
be provided in order for the television to receive the "HD Ready
There may be a UHF input if the television has a built-in DTT tuner.
I imagine, sometime, a bright spark will come up with the idea of an HD to standard convertor that will accept an HD signal and spit out PAL. Perhaps this may be useful if you are madly in love with your existing TV? However in 99.9% of the cases, such a thing will be... well, I'd have to question your sanity if you bought a box to translate HD back into SD (standard definition)! ☺
This information and price guide dates
from early 2007, please consult relevant
trade press/publicity for the current
situation, as it changes very quickly...
Looking in the Argos Autumn/Winter 2006 catalogue, a number of "HD Ready" televisions did not give pixel counts. Those few that did:
|Manuf. / Model
||List price (£ STERLING)
||xx = 27, 32, or 37 (inches)
||1280 × 780
||£599.99, £799.99, £999.99
||1366 × 768
||xx = 26, 32, or 37 (inches)
||1366 × 768
||£799.99, £999.99, £1399.99
||1366 × 768
||xx = 32 or 37 (inches)
||1366 × 768
|Wharfedale HD Plasma TV
||42 inches (plasma)
||1024 × 768
||42 inches (plasma)
||1024 × 768
||42 inches (plasma)
||1024 × 1024
||42 inches (plasma)
||1024 × 1024
||42 inches (plasma)
||1024 × 768
||xx = 37 or 42 (inches, plasma)
||1024 × 720
Only the last two
(three televisions) listed, plus the Panasonic TX26LXD60 (p824) made a mention of the HDMI sockets; while most said things like "Auto setup. Sleep timer. Remote control." All of the televisions quoted visible screen size
, in inches and centimetres.
The resolutions shown in dark red
of the plasma televisions) are rather interesting.
My resource (TeleSatellite, Compil'2007
) says, quote:
Les téléviseurs HD Ready doivent avoir un format d'écran 16/9, disposer d'une résolution d'au moins 1280 x 720, être compatibles avec les signaux HD en 1080i et 720p, c'est-à-dire 1280 x 720 en progressif (720p) en 50 ou 60 Hz et 1920 x 1080 en entrelacé (1080i) en 50 ou 60 Hz, être munis d'une double entrée analogique et numérique (YUV, DVI, et HDMI) et enfin les connecteurs DVI et HDMI soient présents au niveau de la connectique et soient compatibles HDCP. Cet ensemble de paramètres détermine l'apposition du label HD Ready, si un seul élément manque, le téléviseur est recalé. La tendance générale est à la profusion d'écrans HD Ready, c'est une quasi-généralisation dans les tailles de 66 cm à 94 cm du label qui est un gage de sécurité pour le consommateur.
In English (my translation)...
HD Ready televisions must have a widescreen (16:9) display format, with a resolution no less than 1280×720; be compatible with the HD signals 1080i and 720p, that is to say 1280×720 progressive (720p) and 1920×1080 interlaced (1080i), both in either 50 or 60Hz sync; be supplied with both analogue and digital inputs (YUV, DVI, and HDMI); and finally the digital inputs (DVI and HDMI) must be present to the connection level (I guess this means 'not an outdated protocol') and compatible with HDCP. The ensemble of these requirements determine suitability for the label HD Ready. If one requirement is missing, the television fails to qualify. The general tendency is for a profusion of HD Ready televisions, it is almost a generalisation of models in the 66cm to 94cm range, so the label is a pledge for consumer peace-of-mind.
And, well, however which way you slice the cake, 1024 is not
It is very
important to note two things:
- What is quoted above is what applies in FRANCE. If you live elsewhere, you
contact your local Tradings Standards if you think you have been mis-sold a television
that is not as HD as you would like.
- I was once contacted by somebody who had an old (original) HD television which did not
seem to work with the HDCP system. He wondered if he was missold the unit, however I
believed he purchased it before the introduction of HDCP!
The warning is fairly obvious - if you wish to ride the cutting edge of technology, it
is possible that the units will be rendered prematurely obsolete as the devices adapt
themselves to the marketplace (or rather, to the whims of an already hyper-paranoid movie
I would like to say that HD televisions are now commonplace-enough that the devices
should be fairly standardised, but we cannot predict the future. Terrestrial HD
broadcasting is not (yet) a reality in the United Kingdom. If some ass-kicking new codec
comes along soon, it may be this which is adopted for the British terrestrial HD - at the
cost of possible incompatibilities with existing HD televisions.
Put it like this: My little €22,50 DVD player says it plays back DivX. I actually
encode stuff recorded off of TV using XviD or 3ivX because in both cases the results are
much better than my DivX encoder. This content plays on my DVD player because they are
all versions of MPEG4, however some encoded material may suffer picture-freeze or the
video may randomly skip a chunk (minutes at a time!), or fast-forwarding may lead to vast
sync errors between the picture and its soundtrack. Other times, it is perfectly fine and
without problem. The only codec that the DVD player is certified to cope with is DivX.
The use of the others is due to a thankful similarity in encoding, but sometimes it is
different enough to throw the DVD player off the ball.
The use of HD televisions in the future may be fine. You may even question this specific
point with a salesperson and hear him tell you I'm an ill-educated ape that knows nothing
about televisions. Fine, he can say that. Just ask what the upgrade policy is, does the
manufacturer offer flashable updates on their website, etc. And if he should tell you
anything that isn't printed in the user guide, get it in writing with his
signature. If he declines, you might care to wonder who is yanking whose chain...
- HD has evolved since its inception; with better compression, better resolution (such as
full HD or 1080 progressive), and copy protection methods.
You must understand, therefore, that if you bought your television several years ago and
it is not 100% compatible with today, this is just the way it goes unless
somebody was daft enough to sell it to you as "future proof".
However, it is worth checking the manufacture date of any HD equipment that you buy, and
be aware of seemingly good deals just in case a box shifter is trying to offload old
(soon to be obsolete) stock.
Yes, I've just repeated the previous point in a snappier form - I want you to be very
aware of this. No good parting with your hard-earned cash for something that won't offer
you a good service life.
There was no HD compatible video recorder (HDCAM), and no HD compatible DVD recorder in the catalogue. I can't say this is surprising, it is quite new technology.
There were three DVD players (all under £100, on p844) which offered HDMI outputs and would 'upscale' the DVD picture to HD. The £49.99 Goodmans GDVD164HDMI did not quote which form of HD it output. The £69.99 Philips DVP5960 outputs 1080i. The £99.99 Panasonic DVDS52 claims 720p/1080i.
new DVD players can output a progressive scan (my 34 euro Uptek could!), so I'm not sure exactly how much benefit you would see between 576 pixels (standard progressive) and 720p. You would see a difference with 1080i, especially in the horizontal axis as HD natively supports widescreen (rather than the stretch-unstretch method used with existing PAL receivers).
The first totally Full HD
television on the European market is the Pioneer PDP-5000EX. It is a 127cm display which is capable of 1080p
! Yes, that's the highest HD resolution progressively scanned.
means we are asking the television to individually refresh 2,073,600 pixels fifty (or sixty) times per second. Thus it should come as no surprise that the television is priced at around €8990.
In Japan, the Panasonic TH-65PX500 provides the same (up to 1080p
) level of support to a 165cm plasma screen, for around €16,000!
Update: March 2007 - I have seen an advert for a television claiming to be "Full HD" and it is a smidgen under €2000, look how the prices fall in a relatively short length of time.
Udate: October 2007 - within the RadioTimes
listings magazine, Panasonic
is advertising a triple-CCD Full HD video camera that can record into SD cards. I don't know what sort of duration is attainable per gigabyte, nor do I know the price - I expect it would be rather scary. However, a year on, an HD consumer-targeted video camera hits the market. HD is definitely coming.
Where can you buy this stuff? Can it be bought cheaper?
I can tell you that the Pioneer PDP-5000EX can be obtained from Home Cinema shops. That's probably not much use if you don't live someplace in Paris... Some of the other TVs can be purchased from Argos, if you live in the UK. I try to quote model numbers, where I can find them, so that you can Google and comparatively shop. Don't forget to check newsgroups to see if there are any satisfied or dissatisfied customers of the television you intend to purchase.
As for the prices, don't take them too seriously. Obviously they will be subject to radical revisions as the technology improves. Just look how Flash memory keys and MP3 players have plummetted in price - you can now get an MPEG4 capable movie/slide viewer with ~1.5" colour display for less than the price of a 128Mb audio-only player two years ago. That's not to say you should wait forever, that's just to say that this webpage was originally created in December 2006 using materials from the year of 2006. Next year, that €16,000 telly might only cost €9,999...
It means High-bandwidth Digital Copy Protection
. It is supported on the Blu-Ray
and HD DVD
discs, and also on some satellite transmissions. Without a digital HDCP input, your television will not correctly (or at all?) display the desired picture (I am under the impression that you may
see a PAL resolution monochrome
picture, or you may see a blank screen...).
HDCP is supported on the DVI and HDMI inputs, however do not assume that because a TV has one such input, that it also supports HDCP. Check.
While I can understand the movie studios are likely to be behind this, I do wonder if it will be used to restrict our ability to tape stuff "off-air", for example time-shifting. I use the term 'tape' generally, as it is likely to be something with a harddisc inside it... and no
, I don't think a Tivo
would be suitable. I have some stuff here I taped over a month ago and have not yet had time to watch - there's only so much you can fit on a harddisc, but quite a lot you could fit on DVD-Rs.
I think we'll just have to give this time. After all, there are a number of DVD players which are region-inspecific. Many have little 'hacks' which can be used to alter the region code. Software such as DVD Region+CSS Free
will get rid of the region protection on DVDs viewed on a computer, get rid of CSS (so the DVD can be copied), get rid of user prohibitions (such as the annoying "you can't turn off subtitles" - a lot of cheap DVDs on sale in France allow you to have the French dub, or English with
subtitles; how about a free selection of language and subtitles (English for me, or French with subtitles for a person that is hard of hearing?)), and also
apparently it'll get rid of Macrovision if you can't get the TV Out
port to work - but I don't have one of those anyway...
This isn't supposed to be an advert for a randomly-chosen software product, it is intended to show you that the market responds (perhaps slightly less than legally?) to the needs of the users. If I wanted to buy an Australian or American DVD and watch it here, I can. Sometimes this is essential despite
what the studios may try to tell you - because sometimes the versions sold in each country are subtly different. An example: the English release of Amélie
cost slightly more than the French release. The English release was subtitled and had an English-language director's commentary, while the French version came with a second disc of 'extras'. How come the English version couldn't have had the extras disc as well?. Additionally, studios tend to release films at different times in each region. Why?
I'm sure the industry will give you plenty of convincing answers, but in the end I think it comes down to milking more cash out of us viewers. And if all else fails, they can quote billions
in losses due to piracy, which I expect they'll use to justify why new-release DVDs are so expensive, though I don't think anybody knows exactly where that figure comes from...
As I write this (2006/12/06), Casino Royale
is apparently already available for DivX download, this not only pre-empting the DVD releases, but also a lot of cinema showings! I can't speak about the quality (I'd like to think we're beyond the days when people set up 'camcorders' in the cinema!), my computer (at the time) wasn't powerful enough to contemplate DivX!
Point is, to my mind it is the studios
who are woefully behind the times, and while no doubt they pushed for HDCP to be present within the HD system in order to exert some control over what they perceive as rampant piracy and bad ethics on behalf of the viewing public - while, as usual, they failed to see that from time to time their own industry ethics are not exactly virgin white.
It is not my intention to argue whether or not we are justified in copying films. While I've never ripped a DVD, I do tape stuff off TV so if I want to watch a film I like, I can at a time that suits me
without paying for the privilege of movies-on-demand - especially if I really like a movie and feel like watching it three times back-to-back, or if it is one of those peculiar Japanese ones that might take a number of viewings to figure out how all the plot lines come together. I just wanted to make you aware that HDCP is a built-in part of HDTV. In the end, we'll simply need to see how this actually affects us...
"HD Ready" in a nutshell...
The official designation of the label "HD Ready
- A large-resolution screen in "widescreen" (16:9) format.
- A display of 720 lines minimum.
- Compatibility with the two HD formats (720p and 1080i, in both 50Hz and 60Hz).
- Analogue (composite and/or S-Video and/or component) and digital (DVI and/or HDMI)
- Support for HDCP copy protection when connected via digital input.
The label "Full HD
- As above, only with a minimum resolution of 1080 lines. This is supposed to be
progressively scanned (as "HD Ready" already defines 1080i), however some seem to
think this phrase means "it can do both HD resolutions".
Be aware that an "HD Ready
" television may not be technically able to show a 1080i
picture in full quality. Look at the chart above and see how many televisions managed a resolution of 1920×1080...
That's right. None of them.
Instead it will best-match the highest definition picture to the screen matrix in use.
In any case, there is little point in blindly believing the monikers and advertising labels. Instead, simply learn what HD is supposed to provide and then check the quoted specifications
of the device that you plan to purchase.
Be especially careful of the words "interpolated" and "effective". You see, I have a little digital camera that takes images that are 640×480. By using interpolation
to generate an image that is 1280×960, I have a camera with an effective
resolution of 1.2 megapixels. Baloney!
(as Judge Judy might say). The imager, the actual stored picture, is a mere third
of a megapixel. All the driver does is mathematically enlarge the picture - and this is quite evident in the lack of definition in the big version. It is a third-megapixel camera, end of story. The rest is just a lie designed to allow the company to pass it off as a camera with 1.2 megapixels (effective). You're supposed to see the low price and the higher resolution and think "awesome!". It's a lie. An advertising trick. Don't fall for it. Always demand the complete and full specification of what the hardware can actually
[note: my digital camera dates back to when 3mpix cameras were all that and higher resolutions cost silly amounts of money]
This is a complete list of signals that an HD compatible television (to "HD Ready" standard) must be able to cope with:
I think the following may be 'unofficial' but
fairly widely supported for 24fps ciné..?
720? 1080? Interlaced? Progressive? 24fps?
The Sky and Freesat services currently use either 720p or 1080i, though most are broadcasting in 720p, perhaps because it is lower bandwidth? Being progressively scanned, it has been argued as working better for sport than 1080i despite the lower resolution.
1080p is really only used by BluRay/HD-DVD; I am not aware of any broadcaster currently using the 1080p format.
Finally, in common with European television services, films are broadcast at the European standard 25fps (instead of the actual 24fps, this is 1.04% faster). There are no plans to broadcast at 24fps. This is possibly due to many channels simultaneously broadcasting on a standard definition channel (for which a change in frame rate is not an option).
Whatever the French think of their television system and the rest of the world, the bottom line is that their television system (SÉCAM) doesn't even figure in the HD specification. It is further to be considered 'dead' because the majority of those cheapy little FTA satellite receivers, DVD players, and DTT boxes (called TNT in France) are made outside of France, so they just spit out a bog-standard PAL signal.
Whether or not people knew it, most televisions sold in France over the last decade or so have been dual-system compatible. Same with a large number of video recorders. In fact, I have helped to set up a small number of televisions over here for elderly people and the choices offered have been staggering - NTSC? PAL? PAL+? SÉCAM? MESÉCAM? PAL-I? PAL-B? G? Whatever, it isn't a problem for these televisions!
Anyway, while the digital era may herald the demise of several decades of teletext, it looks as if SÉCAM will suffer the same demise...
Is this a problem? Was SÉCAM any good after all?
|Imagine how this would look on TV!|
I think the fairest way to describe SÉCAM is as something "different". PAL's colour broadcasts suffer in the high frequency domain (the schoolgirl wearing a fluourescent gingham pattern uniform, or the politician with the electric shirt). SÉCAM attempted a different way to handle this problem. Which system was better is of little interest as much of Europe told the Americans where they could stick their crappy NTSC and adopted PAL, except the French who gave everybody the finger and went ahead with SÉCAM.
I've watched broadcasts in SÉCAM. Looks just like anything I'd have received off air in the UK in PAL, so I don't think - really - there is any "better" format. They are simply different ways of approaching the same problem.
So why is their no SÉCAM in HD? Perhaps, knowing that much of the hardware has "Made in Germany" and "Made in Japan" all over it, the French knew that continued defence of their system would be a waste of effort, especially as it is quite likely that support for NTSC and PAL within HD is only really for 'legacy' reasons. HD's 720p and 1080i is related to no existing television broadcast standard. It is something altogether new. Furthermore, being provided by component, or digital input, there will no longer be such a thing as an electric tie. Even PAL, with RGB or S-video input can show such without the interference (it only becomes evident with CVBS (composite video, blanking, and sync)) when everything is squished into one waveform. Pretty soon, those days will be behind us.
That is, for the moment, all I can tell you. I just looked (December 2007) through two (French) magazines for an HD compatible FTA satellite receiver, but did not find anything. Shame. If I do see something, I'll let you know.
This is not something specifically covered here as this site concerns satellite reception. Many countries in Europe are rolling out terrestrial high definition services, however within Britain there is none as yet.
My final note...
You've have thought that you'd get a great signal with digital inputs, digital reception, and completely digital television. Unfortunately, the quality of your picture is only as good as the input. It's like you can have a thousand pound audio amplifier with designer speakers that cost more than a family saloon apiece, but if your music is coming from an LP and a worn stylus, it simply won't do justice to the pricey audio kit.
Enter the trade-off between quality and bandwidth. In the days of analogue this was never an issue. Now? Now a broadcaster can choose to drop the bitrate of one station in favour of something else. With a number of the FTA channels, this can be seen. Once you know what MPEG artefacts look like, you'll see them around quite a lot.
I've yet to see MPEG4.H264 in use, I'm just suspicious of claims to fit that much picture into that small a space...
Copyright © 2007/2008 Rick Murray