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Digital TV – where to from here? Freeview with MPEG-4 should be the answer! Digital TV commenced in Australia on 1st January 2001 – yes, nine years ago, making Australia one of the first countries to start regular DTV transmissions. These transmissions now cover 60% of the population but for Australians to get full HD programming, we need MPEG-4 broadcasts. At present, we are being short-changed. By ALAN HUGHES W hat has happened with Digital TV since 2001? As far as programming is concerned, the answer must be “Not much!” Sure, the networks can now transmit both SD and HDTV but there is little that is true HD - and most HD is merely simulcast with the SD programs anyway. Believe it or not, a lot of the do-called “HD” programming is itself up-scaled from SD, which means that it might fill a large screen but quality-wise, it’s no better than the SD program. We’ll explain the important difference between HD and true HD (or more correctly Full HD) shortly. However, on the reception side, there have been considerable developments. Over the last few years, a large proportion of the population has upgraded their TV sets to large-screen LCD or plasma HD sets. Many people have also purchased Blu-Ray players which are recorded at the ‘Full HD’ standard. When connected to a display with an HDMI or component video You don’t have to pay a lot to get Freeview Certification (whatever that actually means – Freeview won’t tell anyone!). This HD Set Top Box was recently being offered through ALDI stores for just $99 – and that includes MHEG-5 interactive middleware enabled, MPEG2 and MPEG4 AVC format decoding and 1080i/720p/576i display modes. 18  Silicon Chip siliconchip.com.au cable, many large-screen TVs and projectors will display the image at this quality. But free-to-air broadcasters and Pay-TV operators do not transmit signals at the ‘Full HD’ standard. Freeview We’ve also been “blessed” with a raft of “new” digital TV programming under the “Freeview” banner but as viewers well know, that hasn’t meant much in the way of new programs. In fact, during 2009 TV channels were forced to change their advertising which claimed Freeview offered a whole lot more than it delivered. With only a few exceptions, most new Freeview channels are simply copies of existing channels. As we said earlier, Australians are being short-changed and there is no sign that this is going to change any time soon. But Freeview is more than TV stations transmitting new digital channels. It’s actually a whole new set of technical standards including (but not limited to) the ability to receive MPEG-4 signals. It’s almost impossible to find out what the Freeview specifications are, unless you are a manufacturer or importer willing to sign a non-disclosure agreement. However, even without the specifications, we can use the Freeview marketing and labelling to ensure any TV set purchased now will be ready for MPEG-4 when it finally arrives. What is MPEG-4? The Motion Picture Expert Group (MPEG) is a body which lays down standards. Australian Free-to-Air TV and SD satellite TV currently use the MPEG-2 standard. In 2007, MPEG-4 was introduced, which creates signals with 30 – 50% smaller data rates than with MPEG-2. The result is that a Full HD signal can now be sent with a data rate of only 8Mb/s. MPEG-4 is presently used only on HD satellite transmissions including Foxtel, handheld TV, plus a number of Free-To-Air (FTA) ground-based TV services, including all New Zealand DTV. Semiconductor manufacturers are now making MPEG-4 decompressor ICs. These will also decompress MPEG-2 because it is a subset of MPEG-4. As a result, there should be no significant increase in receiver price due to the inclusion of MPEG-4 decoding. For example, Aldi stores have been selling a Freeview-approved STB for a similar price to other, non-MPEG4-capable, HD STBs. TV precedents When colour TV was introduced to Australia, there were no separate monochrome and colour transmitters. All receivers, even B&W sets, could display a watchable program from the same transmission. The former equivalent of the ACMA specified that all colour receivers had to incorporate a delay line for colour correction. As a result we had no simple-PAL sets and assuming there No money for MPEG-4? Free-to-air TV stations constantly bleat about insufficient revenue to allow them to adopt new technology such as MPEG-4. But with the Federal Government’s $250 million largesse to free-to-air licencees in the form of slashed licence fees (The Australian, February 8), surely there is now just a little left in the coffers to stop short-changing Australian TV viewers and switch on MPEG-4? was enough signal at the aerial, all colour sets gave good pictures. Similarly, when UHF TV was introduced, even if the TV receiver didn’t have a UHF tuner (and very few did not) just about everyone had a VCR. All video recorders were equipped with a UHF tuner allowing the vast majority the audience to view UHF as well as the original VHF programs. This enabled all broadcasters to roll-out UHF transmission to many regional areas. But now, with digital TV, we have separate HD and SD program streams. They could have completely different content but for the most part, they both have identical programs. Since HD broadcasts started, the price of HD set-top-boxes has plummeted; SD STBs have virtually disappeared from the shops. (Even if SD are still available from your local retailer, we recommend against purchasing them – even if they appear to be an absolute bargain!) Action required What we need now is for the Depart- Here are the developments since 2001. The inner (yellow) rectangle represents the standard CRT screen, capable of displaying only SD (standard definition) pictures. Unfortunately, many of the signal sources even today – including offair “HD” TV signals – are only capable of displaying at this resolution. This will change – but it needs to change faster! siliconchip.com.au March 2010  19 compression and improved error correction. Foxtel HD is already using DVB-S2. This has enabled them to minimise their satellite hire costs for HD programs. The conversion task in Australia A comparison of relative screen sizes from SD, through the various incarnations of “HD”, right up to the full or true HD (in light blue). As this graphic ably demonstrates, even discounting SD, without full HD you are being well and truly shortchanged. And you cannot (yet!) receive full HD signals off-air. ment of Broadband, Communications and the Digital Economy and the Australian Communication and Media Authority to insist all importers that all receivers must be able to produce a viewable program from a Full HD MPEG-4 program. To enable broadcasters to switch over to MPEG-4 receivers need to be able to decompress all MPEG-4 signals, whether they are Full HD or SD. This will then make the need for transmitting an identical SD version of the HD program unnecessary. Even though MPEG-4 offers broadcasters a number of advantages (see tables), experience has shown they loathe spending money: they won’t switch over to MPEG-4 until they are confident that receivers can decompress all MPEG-4 signals. As an aside, in the USA, all colour TV transmissions were to the NTSC standard until 2007. Now NTSC broadcasts have stopped and US TV signals are HD ASTC digital only. So while the USA started digital TV after Australia, they have moved ahead of us with their HD ASTC digital TV. As a result, there has been a considerable increase in the number of HD original programs – which we don’t see! So plenty of HD programs are available and probably most USoriginated TV series we are presently watching are available in HD – at no extra cost! So, to set the ball rolling, we need just one TV broadcast network to start transmitting MPEG-4 programs. The 20  Silicon Chip others will follow suit just so they don’t suffer any marketing disadvantage. Developments since 2001 Currently, we have a model of three commercial broadcasters plus the ABC & SBS. Usually this means five transmitters on five separate channels. Digital TV is more efficient in the use of the spectrum, enabling more than one program to be transmitted by a single transmitter. Local digital TV stations are now radiating extra program streams: TEN and One HD, Nine and GO!, Seven and Seven HD, while the ABC now has ABC2 and ABC3 with SBS also transmitting SBS2. Costs for the broadcasters Provided the entire audience can receive the MPEG-4 programs, the largest cost is the infrastructure used to produce HD programs. The distribution costs are unchanged with the exception of the purchase of HD MPEG-4 compressors for each program stream at the playout centre. Satellite television Currently the Optus Aurora satellite is feeding low powered repeater transmitters and direct-to-home receivers in remote areas of Australia. This system is DVB-S which uses SD MPEG-2 compression. Towards the end of this year the Optus D3 satellite will be launched. To transmit HD through a satellite DVB-S2 is required as it uses MPEG-4 There are about 7.9 million dwellings in Australia. There are 4.2 million dwellings yet to get their first digital receiver. Australia has around 17 million TV sets. Eight million of those sets need to be replaced or at least, used in conjunction with a Set Top Box. The Switchover Taskforce of the Department of Broadband, Communications and the Digital Economy (DBCDE) is funding set top boxes for aged, disability, DVA pensioners, along with carer and DVA income support recipients. The Tender should mandate that only MPEG-4 capable Set Top Boxes be supplied, and where satellite receivers are required, they must be DVB-S2. For reliable DTV reception the tender should also mandate that no antennas designed for any channel between channel 0 – 5A can be supplied. This means that by the start of 2014 at least 53% of households will be able to view HD MPEG-4 signals. Some current DTV viewers will need to feed their digital TV with an MPEG-4 capable Personal Video Recorder or STB because their existing decompression is only capable of MPEG-2. You may have noticed that HD Set Top Boxes are now 10% of the price they were in 2001. Country Western Australia has no commercial DTV. GWN (Prime WA) and WIN are yet to announce a commencement date. Since they only intend to have one digital transmitter per site then the use of MPEG-4 would give either Full HD TV or a greater variety of SD programs. Without commercial DTV there is a much lower proportion of digital TVs. With a viewing population of 500,000 this would be a good place to start using MPEG-4. The ABC’s Role Virtually all of the programming on ABC HD is upconverted ABC1. This does not make the image quality any better than ABC1. The commencement of ABC3 (Childrens channel) would have spread the existing data rate too thin. siliconchip.com.au So the ABC would be better off converting ABC HD to Full HD using MPEG-4. This would require an MPEG-4 encoder for each state so that the local news will be available on ABCHD so the channel doesn’t need to be changed. Even better if they also use an additional MPEG-4 compressor for ABC3. This will accelerate the sales of MPEG-4 capable receivers. Conclusion To future proof TV all new receivers must: • be able to display a full HD MPEG-4 program • have at least 1 HDMI V1.3 input, and STB/PVRs an HDMI output • be MHEG-5 capable • be 24p display capable (Blu-Ray compatible) • All Australian satellite transmissions should be DVB-S2 to enable all of us to have the option of Full HD TV. Importers and manufacturers need to indicate in the specification section of the User’s Manual and on their websites what their receivers are capable of. Broadcasters and the regulators need to bite the bullet and start limited Full HD transmissions with a view to a complete conversion to MPEG-4 transmission at the start of 2014, the start of all digital transmission. This includes the Optus Aurora Free to Air satellite service, which is also used to feed many country transmitters. If DVB-S2 is used then the demodulated satellite signal can be fed into the ground based transmitter without the need for changes in compression. Now that the major US networks are HD capable to their viewers and the Europeans are starting HD transmissions, it is time that our broadcasters use the HD versions of programs where possible. We now have the situation in Australia where an increasing percentage of the audience have better performing equipment than the broadcasters. The lack of Full HD broadcast programs is making manufacturers and retailers’ claims of excellent quality false (except for Blu-Ray disc playback). What is needed is a decision from the DBCDE and Freeview for a start date for the above and an instruction to all importers and manufacturers to implement it. This follows the precedents they set in the past. SC siliconchip.com.au Which set to buy? If you are in the market for a TV, PVR or set top box, which model should you buy? The best answer is to buy one labelled “Freeview Approved” since all such products are capable of MPEG-4 decompression. This applies to all Australian and New Zealand “Freeview Approved” models. Another option would be to look for the Standards Australia ticks, unfortunately the “Australian Standard 4933.1 – 2009 Digital television - Requirements for receivers - VHF/ UHF DVB-T television broadcasts” draft has been placed on hold by Standards Australia, pending the availability of resources. This standard is not mandated by law. You could also look in the specifications section of the user’s instruction manual, however many manufacturers do not specify what compression standards the device can decompress. Download the manual from the manufacturer’s website or look at the manual in the store. Contact the manufacturer or importer and ask them. Which receivers are currently capable of MPEG-4 decoding? The European Union is proposing that all DTV receivers sold after 1st January 2012 should be able to decode MPEG-4 also called H.264/MPEG-4 AVC standard. TV Receivers Blue = MPEG-4 capable Black= 24p capable Cyan = Full HD Orange = >1m diagonal screen Set Top Boxes and Personal Video Recorders Blue = MPEG-4 capable, Yellow = HD Cyan = HDMI capable The data for the above graphs is constantly changing so some brands may be missing or have a greater percentage of the characteristics shown in the graph. The data was obtained from a survey of websites, including downloading the instruction manuals and requests for information from the manufacturers. Most did not reply. March 2010  21