You Ask Freeview thread #3

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#243457 6-Aug-2009 13:35

Hi all,

Could the guys familiar with the MHEG5 EPG system explain a little bit more about it for us all please?

* What I'd like to know is what sort of info is sent, like does it include the graphics etc?
* Is it possible to extract the information from the MHEG5 data to then be used in your own EPG format?

I'm just curious because this may be a big or a small obstacle to PlayTV arriving here officially. If EIT data is not going to be increased above 1-2 shows ahead, then will Sony etc be able to use the MHEG5 data to populate their own EPG or will they have to use the freeview style EPG instead?

Cheers!

Jaxson

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#243462 6-Aug-2009 13:41

RustyGonad: Yea that horrible EIT standard that doesn't let you do anything - unless of course you have a Media Center, then its kind of a nice easy INTERNATIONALLY ACCEPTED STANDARD way to get you guide. And then you can do all that other fancy stuff like series record bla bla bla....But then again thinking about it Sky seems to do quite well with EIT as well in MySky HDi... hmmmm can't be right...

Good to see Freeview standardised on the MHEG standard, except for on Satellite where they use EIT - ahhh why is that again???? Isn't MHEG their preferred standard - nah I must be mistaken.

Also nice to see they took that nice internationally accepted open standard and customised it so that no other gear works on it... But hey there's a couple of Freeview certified boxes. Waiting for PlayTV anyone...

But all the official boxes out there support RED BUTTON services though which means they can do what? Ahhhhh maybe Freeview can get back to us on that one too.

Yea Freeview made the right moves, much better to have internationally accepted standard MHEG which is used in about 5 countries, rather than using those old dog standards like EIT and say Dolby Digital (TVNZ), or some HiDef content maybe... nah much rather have regional ads, MHEG, and a "near DVD" quality picture... And that beautiful AAC sound... At least the guide looks the same...

What I find mildly frustrating is that the EIT broadcast infrastructure is there, it is already setup and being used for now/next info.
Surely this could easily be extended, thereby making it available to the likes of PlayTV, windows media, etc etc? And thereby increasing the number of people utilising the freeview service, and thereby giving them more advertising clout etc?

I'm not really debating if it's better or worse than MHEG5, I'm just saying how about turning up the volume on what's already there.

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#243472 6-Aug-2009 13:54

Jaxson: Hi all,

Could the guys familiar with the MHEG5 EPG system explain a little bit more about it for us all please?

* What I'd like to know is what sort of info is sent, like does it include the graphics etc?
* Is it possible to extract the information from the MHEG5 data to then be used in your own EPG format?

I'm just curious because this may be a big or a small obstacle to PlayTV arriving here officially. If EIT data is not going to be increased above 1-2 shows ahead, then will Sony etc be able to use the MHEG5 data to populate their own EPG or will they have to use the freeview style EPG instead?

Cheers!

Your best bet is to Google MHEG5 and read about it.

It's essentially a middleware programming language that enables you to control interactive features and display graphics onscreen.

The actual EPG data is contained within the MHEG5 data stream and the MHEG5 application generates the static images for the EPG. A MHEG5 PVR spec also definates how the EPG operates in the Freeview PVR.

Extracting the MHEG5 EPG data for your own application can be done easily and there is some code around that did work on Freeview in NZ until a minor update to the way the data was sent broke it.

Source is available if you want to modify it, you just need access to the full TS to decode the MHEG5 data.

sbiddle

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#243473 6-Aug-2009 14:03

Jaxson:What I find mildly frustrating is that the EIT broadcast infrastructure is there, it is already setup and being used for now/next info.
Surely this could easily be extended, thereby making it available to the likes of PlayTV, windows media, etc etc? And thereby increasing the number of people utilising the freeview service, and thereby giving them more advertising clout etc?

I'm not really debating if it's better or worse than MHEG5, I'm just saying how about turning up the volume on what's already there.

Freeview wanted to set clear minimum standards for boxes. This ensures consistant user interfaces across all Freeview devices for the EPG and opens up the potentnail for applications in future that will be accessible on all approved boxes.

Remember that MHEG5 has been deployed on Freeview in the UK for many years. It is not some new standard. Rather than complaining asking why Freeview aren't supporting EIT people should be asking manufacturers why they aren't supporting MHEG5 - a standard that is openly available to developers and used in a large number of DVB broadcasters throughout the world.

dontpanic42

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#243611 6-Aug-2009 18:21

sbiddle: ..........Rather than complaining asking why Freeview aren't supporting EIT people should be asking manufacturers why they aren't supporting MHEG5 - a standard that is openly available to developers and used in a large number of DVB broadcasters throughout the world.

I asked this exact question to DTVS.co.nz for the Vantage unit. Their response was that they were working on some sort of solution that was "still under negotiation". They also mentioned that the cost of developing the required integrated middleware for accessing the MHEG5 info was about NZ500k.

This was back in February when I inquired though.

Here's hoping!

Jaxson

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#243823 7-Aug-2009 09:29

Is there any way of buffering the MHEG5 info? This a developer thing I guess.

I haven't seen the new Zinwell HD PVR but my experience with the standard box MHEG5 EPG is that it's painfully slow between channels/days/weeks etc.

The visual layout is great, clear and shows HD/DD show info is all great.

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#248564 19-Aug-2009 10:54

HybridE506r: Hi, just my 2-cents worth for this interesting topic

I am wondering why analogue is being switched off?

Why close down an entire technology network when the coverage of digital will not meet all expectations.?

...

I am on the Horowhenua coast, vodafone coverage along with DVB-t coverage is simply a gamble at best, there are a lot of people who do live in coastal communities, the question is whether DVT-t coverage will be improved in the near or short term. Phone calls to the freeview 0800 number are useless at best!!!!!!!!!!! UNLESS you ARE BUYING RETAIL "FREEVIEW APPROVED" equipment.

I'm surprised no one has really answered this, or perhaps some has I just missed it but the answer to your first question is simple. Money. The spectrum released by switching off analogue is worth a lot. http://gigaom.com/2009/01/09/delaying-dtv-could-mean-longer-wait-for-lte/ (the US isn't a great comparison since their spectrum plans are fairly different from ours but it does give the general idea)
http://en.wikipedia.org/wiki/Digital_television_transition

While money may seem like a poor reason, remember that this is money that goes to the government and hopefully therefore eventually the people. And the spectrum is bought for a reason, because it will be used for something (one of the questions was concerning Vodafone's and Telecom's wish to have access to the spectrum). Something you may yourself one day use. Or to put it a different way, analog TV is clearly an incredibly inefficient use of the available spectrum. It'll be far better if it's used for something else. Digital TV can have more channels and better quality for the same use of spectrum. Simulcasting both analogue and digital is obviously an even greater waste.

While I appreciate how frustrating it is for those outside DVB-T coverage, NZ's low population density outside of urban areas is always going to cause issues. With satellite service now available, I think there's always going to be questions asked about how far we should extend coverage and how many people should rely on the satellite service. As the Freeview CEO said, coverage will definitely expand as we get closer to the switch off date but it wouldn't surprise me if it remains less then for analog. Obviously the satellite service has issues some caused by the choices made I've mentioned later and also likely the cost of bandwidth there which are unfortunate.

RustyGonad: Good to see Freeview standardised on the MHEG standard, except for on Satellite where they use EIT - ahhh why is that again???? Isn't MHEG their preferred standard - nah I must be mistaken.

Also nice to see they took that nice internationally accepted open standard and customised it so that no other gear works on it... But hey there's a couple of Freeview certified boxes. Waiting for PlayTV anyone...

But all the official boxes out there support RED BUTTON services though which means they can do what? Ahhhhh maybe Freeview can get back to us on that one too.

Yea Freeview made the right moves, much better to have internationally accepted standard MHEG which is used in about 5 countries, rather than using those old dog standards like EIT and say Dolby Digital (TVNZ), or some HiDef content maybe... nah much rather have regional ads, MHEG, and a "near DVD" quality picture... And that beautiful AAC sound... At least the guide looks the same...

AAC is actually an excellent audio codec. It's only real competitor for effieciency in the lossy arena is Vorbis at the current time IMHO. I don't know what One and TV2's problems are, I've only limited experience with DVB-T/FreeviewHD so presume in good faith their audio is really crap. Perhaps they choose a crap bitrate or have crappy equipment. Perhaps more likely it's because they're using HE-AAC even though they have a high bitrate. IIRC I've read before they use a bitrate of 128kbps despite using HE-AAC. (IIRC 128kbps LC is enough to be transparent for a large proportion of listeners on many samples, although that may be VBR.) Conventional wisdom is that you gain nothing but likely lose quality compared to using LC. Perhaps their codecs are good enough that it doesn't matter but I doubt it. I haven't see any evidence that such codecs exist. More likely it's some sort of compatibility/simplicity thing. Or perhaps cost. That way they get the benefits of HE-AAC if they use a low bitrate like 64kbps but don't need to implement both HE-AAC and AAC-LC and the added cost, complexity and other issues that may cause. Personally the tradeoff doesn't seem worth it to me, particularly since if you support HE-AAC it should be much work to support AAC-LC since AFAIK HE-AAC (I presume we're talking about v1) is basically AAC-LC + SBR. But I'm not an audio or software engineer nor do I have any experience with desiging standards. Also it seems that most other people are doing the same so it's probably not just a Freeview decision. But now that I think about it, this may be a good question for the next interview regardless. Unless someone already knows the answer?

In any case, I think it's a good thing they choose AAC rather then some crap like MPEG layer 2 regardless of the oddity of the HC decision. Personally I would have preferred them to choose AAC for their multichannel as well. Probably LC with a decent bitrate perhaps 192kbps or perhaps 256kbps this would easily beat AC3 at 384kbps (I believe this is what TV3 is using right?). Of course it would create problems for outputting the audio to a digital receiver since few support AAC. They'd either need to do LPCM over HDMI or perhaps use some sort of real time DD or DTS encoding (similar to DDL and DTS Connect). But define what you think should be required and let the STB makers handle that. And don't bother with dual streaming except for multiple languages etc. Let the STB makers downmix the 5.1 stream as necessary.

Ironically if they had gone down that route, we would likely have better sound and be using less bandwidth (not a great deal difference but still something). Even those using DD since despite the double compression, outputting a 640kbps AC-3 from a high quality multichannel AAC stream is likely to generally give better results then a 384kbps AC-3. Well presuming the encoder on the STBs/whatever wasn't crap. And there wasn't horrible latency/AV sync issues due to the extra processing which more people will notice then any difference in audio quality.

Then again I also think it would be good if they had DVB-T2. While would likely mean we still wouldn't have Freeview since it hasn't been finalised and NZ's involvement probably wouldn't have speed the process up much. Which probaby explains while I'll never work on a standardisation committee, beyond my lack of experience in such things.

As for the Freeview Satellite issues, I think most here will agree it's a bit of a mess. If they had gone the h.264 + AAC route there as well, there would be making a lot more efficient use of bandwidth. And if they had gone DVB-S2 too... And clearly MHEG-5 on both would have been better. Finally it would have been great if they'd implemented regional advertising without requiring multiple feeds to be transmitted all the time. In other words, transmitting the extra feeds only when needed during advertisements. Of course this would make it trivial for people to remove or skip ads and people not using a Freeview box will generally just see a no signal instead of ads. But who cares? :-P Again of course, all this probably would have delayed things. And who knows what problems the stream switching would have caused (beyond the fact their advertisers would be screaming bloody murder).

Having said that the multichannel AAC thing was definitely possible. I mean Japan and Brazil did it before us (well okay Japan used MPEG-2 AAC) and even though they're not DVB-T that's not really the issue. And I believe some other countries are either trialling or already using DVB-T with multichannel AAC.

BTW, the reason why some of things Freeview does things is only done in a few countries is because we're ahead of the curve of many countries in that tech area (which is partly because our DVB-T is fairly late for a developed one). Yes, it's a rare experience but I wouldn't say it's a bad one. It's clear most broadcasters are moving to MHEG-5. It's also clear that most are likely to use h.264+AAC (either multichannel or with AC-3 multichannel). In some ways, it's probably unsettling since it's not something we experience much but it's not a bad thing. Going MHEG-5 exclusive may seem annoying but despite our small size, it's probably had some positive effect on MHEG-5 support, e.g. I suspect the DVB Viewer devs were partly influenced by the us. It's also worth remembering the codecs and processes for doing h.264 and perhaps particularly HE-AAC broadcasting are unlikely to be at their best yet, so the quality will likely improve over time.

P.S. I'm surprised by these costs I've heard for MHEG-5 middleware. There's a partial implementation for Linux and the DVB Viewer devs are working on an I believe independent implementation and we've already seen some results from that. Even Microsoft are working on something although don't have plans to support us yet IIRC. Obviously these are all normal computer implementation which probably aren't that efficient (i.e. may not work well on an embedded platform) and are likely far from complete, but it still surprises me that people can charge so much to license an implementation if those figures are to be believed. It almost sounds like a market crying out for competition...

browned

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#248569 19-Aug-2009 11:18

RustyGonad: But all the official boxes out there support RED BUTTON services though which means they can do what? Ahhhhh maybe Freeview can get back to us on that one too.

Well in the UK, before HD, the red button would allow for coverage of sport to be moved to a lesser bitrate channel while normal services continued on the main channel. A bit like TV3 with the V8's moving between TV3 and C4, except with the red button C4 wouldn't be used and would continue it's normal programming and the v8's would be broadcast on a hidden channel.

Other services could include radio channels running competitions (teletext style) more details about current music and presenters, etc whetever they want to do.

And pay tv services. Press red to watch this channel, enter details etc and get a text code and enter on screen to watch.

Lots of uses for the red button if and when they get the demand for it.

I would first like to see a HD 5.1 movie channel on Freeview though. I am sure it could work. Sky have so many movie channels (not saying it would compete with them) that really shows the demand for movies at home. The main FTA channels seem to be putting less movies on than years ago, Sat and Sun used to be movie nights, now it seems to be Saturday and Monday depending on other TV series. The station would only need to broadcast from 12 - 12 on startup with kids stuff early on and major block busters later on. Anyway I think it would work but I am not a broadcaster so don't know any different.

cheers
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HybridE506r

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#248589 19-Aug-2009 11:53

re: Reply # 248564

Hi Nil Einne,
yeah sorry my older post was just reflecting some frustration at the dvb-t issues and coverage. I ended up going for a topfield tf6000fe and 650 sat dish with dual lnb as hi-def isnt really important. Im really pleased with the topfield and the reception of D1and D2 satellites.

Deev8

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#248671 19-Aug-2009 16:11

dontpanic42: I asked this exact question to DTVS ... They also mentioned that the cost of developing the required integrated middleware for accessing the MHEG5 info was about NZ500k.

That's nonsense - that kind of money pays for something over 6,000 hours of software development, integration and testing effort using very experienced staff. MHEG5 might be a bit tricky, but it's not that complex. In fact I know online banking systems that have cost significantly less to develop, test and install.

Courtney59

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#248962 20-Aug-2009 11:03

MHEG-5 is currently used in UK, Hong Kong and NZ. Only NZ Freeview transmits a MHEG-5 EPG. All other DVB-T free to air broadcasters worldwide use EIT schedule to provide an 8 day EPG. Broadcasters use EIT for EPG because it is cost efficient and does not require an expensive testing and compliance regime. EPG data received by EIT can be cached in the receiver. MHEG EPG cannot be cached in the receiver, MHEG applications have to be killed every time the channel is changed. It takes time to re-start the MHEG EPG and then acquire all the 8 day schedule data after every channel change.
PVR's require a booking system for recording. The system requires interaction between the MHEG EPG and the host processor firmware. This is a special development for NZ, because this is not required anywhere else in the DVB world. The fact that only Zinwell have released a Freeview compliant PVR demonstrates that this is a difficult and costly development

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#248965 20-Aug-2009 11:14

But Freeview Australia will use a MHEG-5 EPG in its phase 2, so it is going to become the standard in the this part of the world within 2-3 years.

rhysb

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#248966 20-Aug-2009 11:17

sbiddle: there is some code around that did work on Freeview in NZ until a minor update to the way the data was sent broke it.

Isn't that the exact problem with using Mheg5 for the EPG though. There isn't a standard defined for EPG within Mheg5 and one little update can break it.

grolschie

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#249004 20-Aug-2009 12:25

Wouldn't a simple solution be to transmit both MHEG5 and EIT EPGs on DVB-T, and let approved receivers use either? Just my $0.02.

Courtney59

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#249006 20-Aug-2009 12:35

MHEG EPG is specified and controlled by the broadcaster. It is a MHEG application so it should run on any compliant MHEG API.
Australian broadcasters are required by government directive to provide a 8 day EPG in EIT SI. This means there is no compelling reason for manufacturers to change to MHEG EPG, especially since MHEG EPG has access time issues compared to EIT EPG.
Also Freeview is requiring PVR functionality to be compromised by removing skip function. MHEG is a means for broadcasters to take some control by stopping the skipping of commercials from recorded programs.
New UK specification requires LAN port on digital receivers. MHEG applications can use the LAN port to allow access of TV programs from broadcasters websites.
TiVo has LAN port that must be connected to broadband to obtain EPG. The TiVo LAN port also is used to log customer behaviour back to server for the broadcasters.

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