MHEG, although an ETSI standard (ES 202 184), was largely defined by the capabilitis of the chips developed to support it in TVs and set-top boxes.
More recently, MHEG has been enhanced with the "Interaction Channel", which is used to deliver content like BBC iPlayer and applications from the internet. A small, core application is delivered through the digital TV stream in blocks using a data carousel. When all the blocks arrive, the application can be assembled and launched - and then load content through an internet connection.
HbbTV
At its most basic, HbbTV – short for Hybrid Broadcast Broadband TV – is similar to MHEG in that it too can have an application delivered to the television using a data carousel. That application can likewise load additional content from the internet. HbbTV is also an ETSI standard (TS 102 796).
HbbTV doesn't depend on a particular broadcast link or on a particular IP link - it'll work with either
Source: HbbTV Consortium
But MHEG applications usually require a broadcast stream to launch them. You can’t simply stick an MHEG application on the home page of an IPTV front end such as VieraConnect, for instance.
HbbTV applications, however, can be delivered from an application portal in the TV and delivered solely over the internet. So it can support content services from providers who don't have broadcast channels available to them.
HbbTV is based around technologies that will be more familiar to web developers than those of MHEG, including CE-HTML, a specification that includes XHTML, CSS, Ajax and Javascript. Crucially, that makes it accessible to considerably more coders than MHEG, with its more esoteric tech, does. In short, with HbbTV, its supporters claim, content providers can build and release apps that link to their material more quickly.
HbbTV's Javascript API has extensions to provide for TV functionality, such as handling channel changes. And it starts out with an explicit expectation that host TVs have a minimum display resolution of 1280 x 720.
The HbbTV spec corrals standards and technologies, including CE-HTML, DVB and JavaScript, from many existing organisations, such as the Open IPTV Forum and the W3C
Source: HbbTV Consortium
The HbbTV spec also contains a contribution from the Open IPTV Forum, which has defined a set of audio and video formats that should be supported over broadband. Essentially, HbbTV relies on the AVC (H.264) codec for both standard and high-definition video, with either E-AC3 or HE-AAC for audio. Audio streaming services use either MP3 or HE-AAC.
COMMENTS
This is nothing new
So - having looked after the running of Ceefax several years ago, I know that it was indeed a very popular system....I bemoaned the Interactive service, because people wanted bigger better content; and quite frankly, there was never enough bandwidth to offer anything other than a 'basic information' service. A lot of services that were on Ceefax went off to bbc,co.uk; and the quickness of accessing information means that we probably don't miss the teletext services quite so much....
There was a real art of ASCII art that both teletext and ceefax offered; but what I really wanted to say was the delivering content to the TV / computer across the 'airways' is nothing new. Back in the heady days of 1984-1991 [I think], Ceefax used to offer download programmes for the BBC Micro computer - you needed a special teletext decoder for your BBC Micro, and these programs were not generally larger than about 10k in length [remember your average BBC Model B had 32k of RAM], and this process was clunky to watch [there was a status bar even - and your code was retransmitted every minute!!!]
Mode 7
PRINT CHR$(141);"I MISS CEEFAX"
PRINT CHR$(141);"I MISS CEEFAX"
So what are you asking for? If not the morons who build menus on DVDs, then the morons who produce the devices (see Panasonic and its adverts in its EPG)? Or if not the HbbTV consortium, how about the YouView consortium?
Face it, there are precious few people who can build a decent UI (for reasons that are quite frankly beyond me) and the ones who are good at it will probably have a good stab at getting the HbbTV experience as good as they can.
31st February?
No wonder YouView is struggling with delays.
From the UI screenshot they're planning on February 31st - it could be a while before that date comes around :)
Bring it on
I for one love freesat. Anything that extends it and makes it more relevant can only be a good thing.
Ps Freesat - more HD channels pls.
