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Standard low def TV broadcasting

Discussion in 'off topic' started by drummerman, Jan 11, 2019.

  1. davidsrsb

    davidsrsb pfm Member

    NTSC changes hue with phase errors, the narrow bandwidth causes smearing. The US TV standard was optimised to squeeze the maximum number of channels in a cable TV system. PAL was developed by people who cared about quality. SECAM was developed by the country that just likes to do everything differently to everyone else
  2. Jim Audiomisc

    Jim Audiomisc pfm Member

    What really irritates me about NTSC is that the companies that sell classical music on DVD have largely adopted making them to the 'NTSC' standard not 'PAL'. And, yes, they tend to mean the frame rate and resolution, not just the colour system, but then label the entire package as 'NTSC'. Perhaps because they hope punters won't twig that means lower resolution.

    This is particularly annoying when applied to material from Europe orginally recorded and broadcast to PAL standards. In the end I gave up buying such DVDs as many of them look so lousy.
  3. Jim Audiomisc

    Jim Audiomisc pfm Member

    IIUC the plan for the UK is to eventually change all the DVB muxes to T2 and then drop SD. They have kept the T1/SD ones as a legacy for the 'OGP'. (Old Grannie Problem) But in these days when OfCom is a branch of commercialising TV they care less about that then they do about getting in cash from the telcoms who want more of the UHF bands. They're currently clearing another chunk, and that means less bandspace for the TXs. Expect them to do it again in future...
  4. Jim Audiomisc

    Jim Audiomisc pfm Member

    BTW In some ways SD is handy. Main example for me is 'Talking Pictures TV'. On a T2 mux but in SD. Broadcasts ancient films, often in poor source quality but interesting content. Many of the copies of films they have don't have enough resolution for HD to make them look better! But since SD is cheaper to run their channel is an excellent way to see the films, and a good way for TPTV to 'advertise' that you can also buy them on DVD from them. Started off as a 'shoestring' operation.
  5. MJS

    MJS Trade: Consultant at WH Audio

    SD if you're lucky is 720x576, I think I've seen 540 x 576 (will check on Monday). The drive to pack more channels on air constrains the aspect ratio and the bit rate. What starts off as a transmission master at 30 Mbps ends up transmitted around 3 Mbps, and that depends on what's happening to the other channels in the stream as they're all statistically sharing bandwidth. SD also relies on legacy MPEG standards so is not the most efficient user of said bandwidth either. Legacy archives of old standards converted material also plays havoc with the process too and looks absolutely terrible.

    Sadly SD isn't going away anytime soon, at least not in the UK.
  6. darrenyeats

    darrenyeats pfm Member

    ISTM some channels and/or programs are down-sampled to SD much better, and others are terrible.
  7. zippy

    zippy pfm Member

    "Even worse are the people with HD TVs that don't even use the HD channels of whatever they're watching"
    The situation is made worse by the fact that the 'old' channels (BBC1/2, ITV, C4, C5) are still numbered as channels 1-5.
    For people like my ancient Mother, those are the historical channel numbers which she's always used. She rarely strays beyond channel 5 and can't grasp the concept
    of adding 100 to get better pictures. She also cannot figure how to use the menu system to see and choose what to watch.
    I'm sure there are many like her.
    I therefore suggest as a first step that those SD channels are swapped with their equivalent HD (e.g. Channel1 becomes HD, 101 becomes SD, etc).
    That way people will be forced to think about what they're doing!
  8. Derek Wright

    Derek Wright pfm Member

    A better presentation of Channel names and number would be to have them sorted in Alpha Numerica on their Channel name then the channel number. All BBC 1s would be together.
    This would require Sky and other receiving boxes eg Humax etc to do a software change - perhaps to allow the customer to select either Channel name or Channel number sort order.

    However I have read that the BBC had to fight quite hard to get BBC1 on the top of the program guide.
  9. davidsrsb

    davidsrsb pfm Member

    There is no reason why SD cannot use the T2 codecs and use a lower and therefore cheaper bitrate.
  10. gintonic

    gintonic 50 shades of grey pussy cats

    VM have started to move some. So BBC2 HD has now moved to 102, but BBC1 SD remains at 101 (with BBC1 HD still at 108). VM have introduced a function on their V6 box, which if you dial in an SD channel, and there is an equivalent HD channel, you get an on screen message to click the blue button on the handset to go to the HD version.
  11. Jim Audiomisc

    Jim Audiomisc pfm Member

    Indeed. Talking Pictures TV does just that. The snag at present, of course, is that people who still only have a DVB-T1 box can't receive it. However that objection will evaporate in due time. And still having some SD 'channels' makes some sense if they are for rebroadcasting repeated of ancient but interesting SD material. Just that eventually it will come via DVB-T2.

    All assuming, of course, that DVB continues to be broadcast via radio transmissions and not confined to being via the internet/sat. OfCom and the telcos may drive it off UHF completely in time.
  12. formbypc

    formbypc pfm Member

    I watch for the content, not for the quality. If the quality is great, all the better, but it's the content that matters for me.

    If the only version of something I wanted to watch was sourced from a 1983 VHS off-air tape, copied again and again to
    Nth-generation VHS, I'd still watch it if I wanted to see the content ....
    Mullardman and whatsnext like this.
  13. zippy

    zippy pfm Member

    That's a good idea too, though BT seem to be generally not very responsive to user-generated suggestions like that.
  14. gavreid

    gavreid pfm Member

    Remember how fantastic dvd was when it came out in 576p 25 fps. Still holds up at 40 inch (from a distance) really for something well done like e.g. Monsters Inc.
  15. Tony Lockhart

    Tony Lockhart pfm Member


    In your bathroom?

  16. Mullardman

    Mullardman Moderately extreme...

    Absolutely. I love this.

    narabdela likes this.
  17. Yank

    Yank Bulbous Also Tapered

    This is doubly true for restaurants and bars.
  18. gavreid

    gavreid pfm Member

    No in the lake where we sleep ;)
    Tony Lockhart likes this.

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