GregA1503560021 Posted May 7, 2008 Posted May 7, 2008 Hi, At the moment we have multiple 'virtual' channels from each network. channels like "72" or "73" are just pointed back at channel "71". I'm just wondering - technically - if channel 73 could point/redirect to a different network entirely, or can it only take point to data from its own broadcast stream?
pgdownload Posted May 7, 2008 Posted May 7, 2008 Your first thought is correct. There is a single stream of actual data of which channels 71, 72, 73 etc. all point to. Now the network can indeed add in another stream of data and switch say channel 72 to point to it instead (as you already have a 'channel 72' on your STB this is completely seamless (ie no need to rescan) and this is one reason channel 7 set up their virtual channels this way. BUT The big issue is bandwidth. There is simply not enough space for any network to broadcast another SD channel. A while back 7 did indeed broadcast a new tennis 'extra channel' which was basically a very low resolution info channel (basically a glorified VPG) so it could fit that in. If the networks are to really add channels they'll either have to canabalise bandwidth from the HD channel (probably could do that without much impact on HD PQ and get another single SD channel) or they'll have to wait for the analogue network to be shut down and extra bandwidth to thus become available. Regards Peter Gillespie PS And yes, each network can only point to the datastream in its own mux I believe. Not sure why you think channel 7 would want to broadcast channel 10's channels anyway?
GregA1503560021 Posted May 7, 2008 Author Posted May 7, 2008 yes, each network can only point to the datastream in its own mux I believe. Not sure why you think channel 7 would want to broadcast channel 10's channels anyway? Actually, I was wondering more about the ABC. The ABC wants one day to have a 24hour news channel. Their charter is to help us to watch and develop australian content, get news, to encourage education/learning etc - and THEORETICALLY they might not care where that's sourced (lets ignore reality!) IF they could point to other TV channels, they could easily setup an Australian News that does something like 7am-10am point to ABC2 (lateline, news, etc) 10am? 10:30 point to ABC1 ("Behind the News") 11am point to Nine News 11:30 point to Seven News 12:00 point to ABC1 News then Press club 1:30 ? 2:30 point to SBS - Dateline, business report etc 4:30 point to Nine News 5pm point to Ten news 5:30 point to TenHD News? 6pm point to Seven News 6:30 point to SBS World News 7pm point to ABC1 News 7:30 point to ABC1 4 Corners or whatever etc etc It would be difficult to co-ordinate, even if they started by generalising on Sydney's 7/9/10 guides. But it would put together an interesting news channel that someone could leave on in the background - if that's what they wanted. But if it's technically impossible, it's technically impossible!
DrP Posted May 7, 2008 Posted May 7, 2008 DVB certainly allows for things like that to happen, but the biggest headache would be what frequency is the other network transmitting on and then you'd have to persuade that commercial network to carry relevant entries in their tables too. So not impossible, but certainly impractical.
pgdownload Posted May 7, 2008 Posted May 7, 2008 Seriously clever idea but not one I suspect you'll ever see. The ABC2 is actually a 100% pre-programmed channel (ie every thing broadcast on it has been setup and scheduled a week ahead of time) This is apparently already a stretch for the ABC and trying to keep on top of a constantly changing schedule would seem to be beyond them. There's also issues like ABC News showing network 10 ads? Network news rating drop as viewers tune into teh ABC version. Who decides ch7 gets the coveted 6pm slot? And as DrP notes the copyright bun fights would be a problem. Not sure how most STBs would go with the ABC constantly refreshing its LCN number to point to particular frequencies (I'd assume most would require a rescan) and to think that after 10 years+ they still haven't got something as broadcasting the time and DLS sorted. Regards Peter Gillespie
dax Posted May 7, 2008 Posted May 7, 2008 I think you have problems even if you changed your muxing on-the-fly within your own services. Does the DVB spec allow for the PAT or PMT table to change on the fly? A PVR thats recording is possibly using a simple pid filter based on the pids listed in the PMT and might not check to see if these change, just keeps blindly recording the same elementary streams. Certainly one that told you to go to another frequency would be a problem! Once its gone over there how would it know to come back??
DrP Posted May 7, 2008 Posted May 7, 2008 It most certainly does. It even has a PAT version number to help the process along. The issue with changing the configuration with in a networks mux is entirely due to non-compliant crap being sold in Australia. Any decent box will happily monitor all the relevant tables in the transmission and react accordingly. Price is not an indicator of decency either. As I said before, frequencies and getting the other network to co-operate would be big headaches. The frequencies change from location to location so that would immediately mean an insurmountable problem for statewide broadcasters such as ABC. So while ABC could transmit tables that say program 29 can be found on a different mux to the one currently being received, it couldn't specify the frequency to tune to get get to that mux. Assuming that issue was some how passed, the other network would have to be convinced to carry info to say that program 29 was here so the STB could find it once it retuned. Then another issue, getting the 'other' network to update its info for program 29 to kick it onto where ever next. The idea could be quite workable in the UK where they have a far more intelligently set up system.
GregA1503560021 Posted May 7, 2008 Author Posted May 7, 2008 (edited) All up sounds a bit beyond what the system can do currently eh?. Seriously clever idea but not one I suspect you'll ever see. The ABC2 is actually a 100% pre-programmed channel (ie every thing broadcast on it has been setup and scheduled a week ahead of time) This is apparently already a stretch for the ABC and trying to keep on top of a constantly changing schedule would seem to be beyond them. There's also issues like ABC News showing network 10 ads? Network news rating drop as viewers tune into teh ABC version. Who decides ch7 gets the coveted 6pm slot? And as DrP notes the copyright bun fights would be a problem. Thanks for the compliment. Good point on adjusting to a changing schedule, especially extrapolated over Australia. As for ads - I'd think the opposite would be more of a problem, if they removed the Network 10 ads from a 10 show and replaced with ABC network info or whatever... 10 would not be happy. I don't think having ads kept would really matter, ABC would not profit from them, and as viewers we don't have to watch the channel... it would simply be an extra service we may choose to use. (Yeah... 7 & 9 would fight to be on the "virtual channel"... then again, perhaps that would help get their agreement to work with ABC?. In my example, I loosely gave 7 one slot and 9 the other. ) frequencies and getting the other network to co-operate would be big headaches. The frequencies change from location to location so that would immediately mean an insurmountable problem for statewide broadcasters such as ABC. So while ABC could transmit tables that say program 29 can be found on a different mux to the one currently being received, it couldn't specify the frequency to tune to get get to that mux. Assuming that issue was some how passed, the other network would have to be convinced to carry info to say that program 29 was here so the STB could find it once it retuned. Then another issue, getting the 'other' network to update its info for program 29 to kick it onto where ever next. It can't just use "channel 71" eh? (is that reasonably universal?) I moved 300 metres up the road - and all the frequencies I use to get 2/7/9/10 changed. I used to be behind a hill and couldn't see Sydney or receive anything transmitted there so used a repeater. 7 is still listed as "7" - but from what you're saying a set top box would have to actually specify the exact frequency rather than the channel identifier (if that's the right term). Even then, if it could pass us across to 7 news, it would have no way of knowing how (or when) to come back. There simply is no way to say "come back in 30 mins", or a more complicated end of program instruction that a partner network would have to add to "Send this viewer back to 'Australia News' if this is how they got here." The idea could be quite workable in the UK where they have a far more intelligently set up system. I find the concept interesting - especially in light of the ABC's charter. ABC already helps new shows get started and then sells them off to the networks - why not highlight good programs on other networks, programs that fall under the charter goals? Perhaps in a couple of years we'll get a similar option through other means. Edited May 7, 2008 by GregA
DrP Posted May 7, 2008 Posted May 7, 2008 No, it can't just use channel '71', because channel 71 is a logical structure. Your STB has to be told what makes channel 71 up and where to find it.
alanh Posted May 7, 2008 Posted May 7, 2008 All, This is what an Electronic Program Guide is for. Personal Video Recorders, particularly allow you to choose programs by name. So if EPGs were to be transmitted correctly by the networks they would contain a week's programs. The programs starts and ends would be accurate. If the were generated by the computer which is used to control program play out to the transmitters it would be with a minimum of human intervention and hence cost. Each Digital Transmitter emits a Logical Channel Number and a set of multiplexes complete with a name for each. A LCN is broadcast brand name and does not reflect the real channel number used by the transmitter. This can be found during installation. Logical Channel Numbers 1## TEN metropolian 6## SEVEN affiliate eg. Prime & GWN 2## ABC 7## SEVEN metropolian 3## SBS 8## NINE affiliates eg. WIN & NBN 4## miscellaneous 9## NINE metropolian 5## TEN affiliate such as Southern Cross When the STB is set up it will look for real channels and then receive and store the the LCN for each signal. So when changing channels the receiver will switch the tuner to the memorised channels and they will line up with the the most significant digit in the logical channel number. The ## numbers indicate which mux number will be decoded. If you are trying to use another network's empty channel space, this will be subject to commercial arrangements, however the first digit must be of the network transmitting the signal, otherwise the tuner will not select the signal containing the wanted program. The other problem with this suggestion is that networks purposely make programs overlaps. So the short of this is that no changes to signals is required, but the user will need a PVR to do selection and recording of overlapping programs. If the ABC were to set up the news channel as you suggested it would have to pay the other networks to duplicate their programs. I would rather they put this money into real program production. They tried before to get a news channel up and wasted a lot of money on it. Who wants another CNN, BBC Worldwide with headlines repeated continuously instead of some real investigative journalism. AlanH
GregA1503560021 Posted May 7, 2008 Author Posted May 7, 2008 (edited) No, it can't just use channel '71', because channel 71 is a logical structure. Your STB has to be told what makes channel 71 up and where to find it. Obviously I can tell my decoder to go to channel 71, by pressing 7 then 1. You are saying that another channel can't redirect using the same logic - obviously it's plausible to do so, it just doesn't work that way currently. I would assume this is because we would be creating a new channel (eg LCN 78) and you cant tell it to use a different LCN within it, you have to tell it a frequency? If you are trying to use another network's empty channel space, this will be subject to commercial arrangements<snip>If the ABC were to set up the news channel as you suggested it would have to pay the other networks to duplicate their programs. I would rather they put this money into real program production. They tried before to get a news channel up and wasted a lot of money on it. Of course, it would be ABC using a tiny part of its own spectrum to use another channels ACTIVE channel space, not empty channel space. Right? Would it need to pay? In some ways, wouldn't it just be a "recommended viewing list" which automatically changed the channels for you at the right time? I too wouldn't want the ABC to pay for the privilege, though I do think it would be worth putting a package together (which would have a cost to it) - IF it was feasible (which, from all the answers above, it wouldn't seem to be). On another note: This channel idea would get much more interesting if you could pick a theme of shows and have it whittle down from 200 pay channels. Edited May 7, 2008 by GregA
alanh Posted May 7, 2008 Posted May 7, 2008 GregA, I'm not quite sure what you are trying to do. If the ABC is to radiate another network's programs, the source of the programs will only sell the programs to the ABC. This is what happens now, except for pooled resources or tiny excerpts. Remember that news departments are quite often the most competitive parts of a TV station. If the ABC were to tell the receiver to switch to another channel's transmitter, the ABC cannot force the viewer back again unless the other network were to do this. This is highly unlikely, because another network would not like to tell viewers to go away. In addition the ABC would loose editorial control which they would violently object to. Since the video cassette recorder has all but disappeared from retailers, the viewers will be selecting their viewing by program name in PVRs. They will not need to know which logical channel number is to be used. As they become cheaper the STB will disappear as well. For example the audio cassette machine which contains a radio tuner took over from a radio alone. The EPG usually displays a synopsis of the program as well when the cursor is over the program name in a PVR. You can see the same information in the now and next displays when you press the green i button on the Set Top Box. AlanH
DrP Posted May 7, 2008 Posted May 7, 2008 I would assume this is because we would be creating a new channel (eg LCN 78) and you cant tell it to use a different LCN within it, you have to tell it a frequency? A verbose description of what would have to happen for this to work and why it wouldn't work has already been given, go back and read it again.
GregA1503560021 Posted May 23, 2008 Author Posted May 23, 2008 A verbose description of what would have to happen for this to work and why it wouldn't work has already been given, go back and read it again. Sorry to reply so late - I read this and shook my head, so just went on doing other stuff I needed to do. Then forgot. This is why I shook my head... - I read a verbose, complex description of how a redirection works (which is great) - I summarise my understanding (in light of other thoughts) and hope to find out if my understanding of the verbose is correct - You tell me to read the verbose again to get the answer to my question. I'm glad face to face communication doesn't do the above much! Imagine if every time someone explained something in detail, you checked by saying "so what you mean is basically X?" - and they just repeated the original again
GregA1503560021 Posted May 23, 2008 Author Posted May 23, 2008 Thanks all for your replies. The intent of my question was partially based around my thought that ABC's charter to encourage Australian content (etc) does not just have to be done by buying Australian content - it can also be done by advertising content on other channels (sacrilige!) or linking in some way. As technology improves, a channel will increasingly be like a "package" of shows in a certain order, and it may be that a channel will change in it's meaning (eg: a Family Channel may just help you find appropriate content, wherever it may be). Anyway - although I was asking about TV, the closest analogy to my question is something like a website which redirects to another site (but dynamically changing where it redirects depending on time of day), or a website which inserts another website inside its frame (which many websites specifically prohibit - but I'm not sure of the legality). I imagine there'd be some legal complaints at the least, and it sounds like the technical requirement is difficult (due to a need to identify the frequency not just the channel name), and logistically very complicated with similar channels nationwide showing slight differences and delays to actual start times of programs, etc. It'll be interesting to watch the evolution of TV, generally
wsmunday Posted May 23, 2008 Posted May 23, 2008 Thanks all for your replies. The intent of my question was partially based around my thought that ABC's charter to encourage Australian content (etc) does not just have to be done by buying Australian content - it can also be done by advertising content on other channels (sacrilige!) or linking in some way. As technology improves, a channel will increasingly be like a "package" of shows in a certain order, and it may be that a channel will change in it's meaning (eg: a Family Channel may just help you find appropriate content, wherever it may be). Anyway - although I was asking about TV, the closest analogy to my question is something like a website which redirects to another site (but dynamically changing where it redirects depending on time of day), or a website which inserts another website inside its frame (which many websites specifically prohibit - but I'm not sure of the legality). I imagine there'd be some legal complaints at the least, and it sounds like the technical requirement is difficult (due to a need to identify the frequency not just the channel name), and logistically very complicated with similar channels nationwide showing slight differences and delays to actual start times of programs, etc. It'll be interesting to watch the evolution of TV, generally Ok what you are suggesting will be possible on an indervidual sence when TIVO is released in Australia. TIVO allows you to setup personal channels, so you could setup a personal news channel that will record all the news and current affairs show during the day and when you are ready to watch you just simple select news from the TIVO menu. and this can be done for all genures, kids, comedy, drama ect...
GregA1503560021 Posted May 23, 2008 Author Posted May 23, 2008 TIVO allows you to setup personal channels, so you could setup a personal news channel that will record all the news and current affairs .... Thanks for the info. Can it be set to only record the last 2 News programs? Or only 5 hours of kids stuff?
wsmunday Posted May 27, 2008 Posted May 27, 2008 Thanks for the info.Can it be set to only record the last 2 News programs? Or only 5 hours of kids stuff? I'm not a hundred percent sure but i don't see why not.
GregA1503560021 Posted May 29, 2008 Author Posted May 29, 2008 I'm not a hundred percent sure but i don't see why not. If you're not sure, I'd assume it doesn't. Mainly because it's actually quite a lot more complicated than just saying "record all news programs". As a simple example - I automatically record 7 news each night at 6pm, and sometimes I watch it. It's easy to set it to record, but to tell my Toppy to delete yesterday's 7 news whenever it records today's 7 news is more 'advanced'. (or much harder - keep the last 3 news programs recorded on any channel but delete any older news) Perhaps there's some TAP I don't know about that does that - but the function would be interesting to me.
pgdownload Posted May 29, 2008 Posted May 29, 2008 Perhaps there's some TAP I don't know about that does that - but the function would be interesting to me.There are several auto delete TAPs on the Toppy that allow you to automatically retire shows like the news after a set period (in this case 24 hours). However the question was on the Tivo, which I don't think has enormous sophistication in this area.http://www.tapworld.net/content/view/111/29/ Regards Peter Gillespie
bevancoleman Posted May 29, 2008 Posted May 29, 2008 Thanks for the info.Can it be set to only record the last 2 News programs? Or only 5 hours of kids stuff? Depnding on exactly what you mean, then yes it can as can most HTPCs. If you want to only keep the last x news recodings from any channel you can do that. If you want to only keep the recordings for x (say... 1) days, then thats also possiable. If you want to do this by groups (i.e. news) then thats possiable, or by indervidual programs, thats also possiable. I don't think you can specify x *hours* to keep though... but you could certainly define how many kids programs to keep, and for how many days.
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