Starburst said:
I have no direct experience of US telly but the listings for the major networks indicate which shows are HD simulcast, it has certainly never been apparent to me that there are dedicated network simulcast 24/7 channels showing upconverted material when native HD is not an option.
In the US it is common for the HD and SD analogue outputs of a station to be simulcast. The network provides HD feeds of the HD shows, and SD upconverts of the SD shows, alongside a network SD feed. Local stations also upconvert their local SD programming - and most importantly their adverts.
Most nets send a high data rate MPEG2 HD feed, which is decoded by the local station, processed, and then re-encoded for broadcast.
Fox is the odd one out, as it moved to HD more recently. It distributes a transmission data rate network feed directly to affiliates, and they don't recode for transmission - they just pass it on through a "splicer" that allows for local logos to be burned in in the MPEG2 domain, as well as allowing stations to cut to local SD->HD upconverts for commercials, local shows etc.
It is quite common for US local stations to get the switching between SD and HD wrong, and for them to upconvert an SD version of an HD show rather than showing the HD feed - with a switch being thrown mid-show in some cases.
The HD in the listings is to flag up which shows are actually produced and broadcast in HD (local stations permitting) - the actual HD streams are usually running 24/7. (PBS is different)
Happy to be proved wrong but a quick look on the NBC and ABC websites shows many shows that are not in HD, so they are either SD or unadvertised HD upconverts.
There is still a lot of 4:3 SD (and a small amount of 16:9 SD) production. These shows will be upconverted to HD on the HD feeds from stations.
A lot of NY studios are being upgraded to HD this summer - so the new series of Saturday Night Live will be in HD, as I believe will Good Morning America at some point in the near future (they are currently producing from an outside broadcast truck AIUI)
To me it looks like a broadcaster can trigger the STB to flick between a SD and HD broadcast at will or heaven forbid tells the viewer that HD content is on Channel X while the current channel remains SD leaving them with the extreme effort required to press a button
Whilst this is technically possible (though switching streams is not easy to implement in a practical operational manner - and would cause nasty switching issues) it isn't what is done.
In the US - when you tune to "ABC Channel 7 HD" (which is likely to be on a different RF channel to 7, which is the analogue channel number!) you will likely get a single HD stream containing the same output in programme and commercial terms as analogue ABC Channel 7 - but with SD material upconverted to HD, and HD material presented in HD. You may also find a few multi-cast SD channels, like a local weather radar loop, a news channel or a repeat of the local news etc. By law the US broadcasters have to simulcast at least an SD digital version of their analogue SD service - though most simulcast in HD (PBS is different).
When NBC showed the Athens Olympics in HD, their HD and SD services WERE different, and I believe they had to approac the FCC (or similar) for permission to show different things on analogue and digital (for the stations that couldn't run an HD service AND an SD simulcast)
This is one of those times when a US viewers direct experience would be most welcome
AVSForum is a good place to find out about this stuff. I've just got back from a trip to the US - and saw some of the studios in question.
However it is done I would consider a PAY service which has a high percentage of upconverts to be fraudulent, for something like the BBC well that's less of an issue although at the end of the day it's all down to what you personally accept as reasonable.
For many HD itself is unreasonable
I think as long as the material is correctly flagged and SD material isn't passed on as HD then it shouldn't be an issue.
It may well be different for channels like Sky Sports - where they may be able to create a standalone HD channel. For a general channel like BBC One or Sky One then it would be more of an issue - I suspect it would only work if they re-named the channels to differentiate - say "BBC HD" rather than "BBC One HD"
I can't see any difference between flipping from BBC1 to SKY1 to CH4 then back to BBC1 when compared to BBC1 HD to BBC1 SD to SKY1 SD to SKY1 HD then CH4 SD for example. It's exactly what we do today be it on DTT, Dsat or cable.
I thought you were suggesting that BBC One HD would be part-time and only carry output when BBC One was showing HD shows. Can you imagine how annoying it would be to have to flip back to BBC One SD from BBC One HD if the channels weren't simulcasts of each other?
I wasn't implying that it was, however there are changes afoot with MIX becoming SKY2 and SKY3 appearing on Freeivew and Dsat (PAY obviously).
It isn't that far fetched to assume that SKY1 itself will be impacted by these changes and the upcoming HD variant must play some part in the programming chosen if indeed it is a simulcast service.
Or so I would have thought
I don't expect any current or future program purchased for SKY1 to be HD only, however it would not surprise me to see programming only shown in SD, maybe moved to SKY2 and SKY3 as influenced by age/broadcast rights etc.
I suspect that the relevance of the programming to the target audience of the channel would be the bigger issue. For example I can't see Sky shunting the Simpsons off Sky One because it isn't produced in HD...