Is there Dolby digital on DVB-T2? (When transmitted)

Discussion in 'Home Entertainment Computers' started by bfrost, Jul 29, 2012.

  1. bfrost

    bfrost
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    I've just completed setting up a new Media Center with a Black Gold 3600 card which has dual DVB-S and dual DVB-T2. My MCE is connected via SP/DIF optical to a Denon AV receiver. This is all now working fine. I notice however that BBC HD channel 108 on Freesat is transmitting in Dolby Digital (as indicated on the Denon) but if I switch to BBC HD channel on DVB-T2 (54) there is no indication and the AV receiver reverts to Stereo. When I look up info on DVB-T2 it seems that Dolby Digital is 'mentioned' a lot but as I said above, my experience does not bear this out. Are the HD channels on DVB-T2 only stereo?
    Thanks.
    Brian.
     
  2. grahamlthompson

    grahamlthompson
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    Freeview-HD uses he-aac audio either 2.0 or 5.1. You need to be able to transcode aac to ac3 (Dolby Digital).
     
  3. Badger0-0

    Badger0-0
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    Yep, way to go Freeview, I don't think :thumbsdow
     
  4. jameson_uk

    jameson_uk
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    Not sure why this is so bad. I am not sure of the details but my understanding that AAC HE can have better sound quality than DD and requires far less licensing than DD.

    With most people using HDMI to amps then passing this as LPCM is actually better than more compressed DD (at least comparing HD channels on DVB-T2 to DVB-S2 seems to make me think this)
     
  5. Badger0-0

    Badger0-0
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    It's fine as long as your box can transcode AAC-HE to DD.
    My Sharp TU-T2 can't (and never will, I've asked them).

    Hence it's stereo only for me, via my HDMI equipped Onkyo amp.

    That's what you get when Britain goes against the rest of Europe and doesn't bother to inform the manufacturers early enough, it seems.
     
  6. jameson_uk

    jameson_uk
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    Not that it helps but I believe AAC has actually been part of the DVB specs for a while so in theory any DVB broadcaster could have been using it.
    Advanced Audio Coding - Wikipedia, the free encyclopedia

    Indeed I think many of our neighbours have been using AAC (sometimes with standard DVB-T) for a while now.

    I am quite surprised that a Feeview HD certified box does not have to output AAC as LPCM though. I am assuming it is decoding but you are only getting the front two channels or down mixed 5.1 ?
     
  7. Badger0-0

    Badger0-0
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    No, it doesn't do AAC at all :)

    My understanding is that although it might have been part of the spec, no one in Europe actually uses it, us apart, hence it was never implemented.
    The only reason we've used it is because of the requirement for audio description (no bad thing).

    All I know is I have a box that will never do 5.1 :thumbsdow

    I could be wrong in parts, but I've basically given up tbh.
     
  8. Badger0-0

    Badger0-0
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    Having re-read Graham's earlier response, I probably need to correct things.

    I either get AAC 2.0 or 5.1 downmixed to stereo, as you suggested, Jameson_uk :smashin:
     
  9. bfrost

    bfrost
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    Thanks for all your help. Has anyone got a definitive setup for transcoding on Media Center? I've tried a couple of the solutions on the net without success.
    Thanks.
     
  10. imilne

    imilne
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    I never use Media Center so don't know what its support for third party decoders is like, but the latest version of ac3filter can decode AAC* and output as 5.1 DD on the fly. Similarly, you could use ReClock to do on-the-fly transcoding to DD. Both would be spdif compatible.

    * I don't have Freeview HD so can't be sure it can decode the HE-AAC that it uses though.
     
  11. bfrost

    bfrost
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    Thanks for your help. I will investifate ac3filter.
    Regards.
     
  12. Rambles

    Rambles
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    In 7MC I got Reclock to work to a fashion (using WASAPI) but it wasn't 100% reliable.

    From what I recall it was not possible to get 7MC to use third party codecs for tv, but it was quite a while ago that I tried so there may now be other solutions available.

    You can set the Windows speaker settings to 5.1 and it will send HE-AAC 5.1 to the amp as PCM 5.1, which sounds great, but it also sends stereo to the amp as PCM 5.1 with three channels of silence, so that breaks the amps ability to use pro-logic (or Neo 6 Cinema in my case).

    I had a look at the new AC3 filter and failed to get it to transcode HE-AAC, that doesn't mean it's not possible though, it may have been user error!

    Now I am using Media Portal I can transcode HE-AAC to DD using ffdshow as a post processor for both live and recorded TV. There is also the new mediaportal audio renderer which enables WASAPI so will send HE-AAC 5.1 to the amp as PCM 5.1, without breaking stereo to pro-logic conversion.
     
    Last edited: May 27, 2017
  13. bfrost

    bfrost
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    Hi Lisa,
    I had seen other of your interesting posts when I was doing research last night, of which the most interesting for me was your evangelising re MediaPortal. As a result, late last night I downloaded it had a play. I must say that I am very impressed with its depth, although for a newbie getting DVB-T2 channels was tricky although I managed it in the end. I'm seriously considering migrating my two Media Center machines to MP, and I love the ability to record more channels than you have tuners. Amazing. I'd really like a skin for MP which is as simple as possible and close to MCE. Does such a 'look' exist? Also, are there lookup tables for UK Terrestrial Freeview HD and Freesat? Or do you have to roll your own?
    Thanks
    Brian.
     
  14. Rambles

    Rambles
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    Ha, cool :)

    I use the Avalon skin, I have tried them all and that's my favourite so far. It's quite simple.

    When scanning for channels in the TV Server configuration I just point to the transmitter that I use (Crystal Palace) and hit scan for channels. Seems to work fine.

    I also use the DVB EPG (over the air) that also now works with DVB-T2 but you only get a 7 day guide. I think you can get more days with other EPG options, but I try and keep the set up simple so I haven't bothered with that.

    I only have Freeview so no Freesat - not sure what you mean by 'look up tables' actually?

    I hope MP works out for you - it is not perfect but I personally do prefer it over 7MC now.
     
    Last edited: May 29, 2017
  15. bfrost

    bfrost
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    Thanks. I'll look at that skin.
    I may have broken something with MP last night then, when I pointed it at Rowridge it only found DVB-T, not DVB-T2. Later I did another scan with 'all regions' and that found DVB-T2 (took a lot longer though). As yet I've not tried to set up FreeSat, hopefully tonight. By 'lookup tables' I was meaning where MP gets its knowledge of the Muxes available on each transmitter and for Freesat, the satellite frequency info.
    Regards, Brian.
     
  16. Rambles

    Rambles
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    Maybe the Rowbridge transmitter details have not been updated with post DSO frequencies? By scanning all it has obviously checked the whole spectrum. You only have to do it once though so it should be set now.

    Not sure about Freesat - have you seen Robbo's guide for MediaPortal - sticky at the top- it is very comprehensive.
     
    Last edited: May 27, 2017
  17. imilne

    imilne
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    The OP is using spdif though, rather than HDMI, so I don't think that would work. The maximum for PCM via spdif is just 2.0.

    I'd also suggest checking out NextPVR (in addition to Media Portal) if you're thinking of jumping ship. You'll get a much better TV experience with either of them.
     
  18. EndlessWaves

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    A sound card that supports DTS Interactive (Connect) or Dolby Digital Live would solve that, and it'd also give you back virtualised surround sound capability.
     

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