How can rg6 coxial pipeline hd+dolby digital together...

Discussion in 'Home Theater Projects' started by JohnTKline, Nov 3, 2003.

  1. JohnTKline

    JohnTKline Stunt Coordinator

    Oct 6, 2002
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    How can rg6 coaxial pipeline hd+dolby digital together? This is something that perplexes me:

    I have an outdoor antenna with coax cable running to my external hi-def decoder box, which then connects through component(1080i) to the tv and optical to the a/v reciever for dolby digital.

    I'm just curious why we need component, optical, etc. , when coax is pipelining both signals to the box and the hd box does the decoding. Why do we need component, firewire, dvi, optical, etc...

    Help me understand how this works.

  2. Stephen Tu

    Stephen Tu Screenwriter

    Apr 26, 1999
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    It's all just compressed digital data, packets containing lots of bits coming in, some packets containing video, others audio. The packets have header information so the decoder knows which is which and what to do with it.

    It extracts the Dolby digital data from the audio packets & diverts it to your receiver via SPDIF digital coax or Toslink optical, to your receiver's DD decoder. One could just put the DD decoder in the STB & decode there, but it makes more sense to do this at the receiver, since that chip could handle DD from your DVD player as well.

    For the video data it has to decode and convert to an analog signal, which is carried on the component cables to your TV.

    One could just build the decoder electronics into the TV, and just plug the one antenna cable into the TV, but different electronics are required for tuning OTA, cable, and satellite. So it makes some sense to have the decoder box separate so the user can just buy/rent the type he needs, and just send the decoded video signal to the TV.

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