[mythtv-users] Possibly a "dumb" question

[Jim Morton]

Brian Wood wrote:
> On Friday 05 February 2010 08:40:52 am Jim Morton wrote:
>   
>> Can someone explain this to me? I just don't get it...
>>
>> Myth records shows as mpeg or whatever is being broadcast with no
>> decoding or other changes effectively capturing it unaltered.
>> During playback, Myth has a myriad of ways to process and render
>> video/audio to then deliver to the TV.
>> Why can't it just stream the exact file to the TV and let the TV tuner
>> receive/decode/render/interlace/deinterlace it. In other words hand it
>> to the TV exactly as it were broadcast.
>>
>> I believe cable boxes do just that. Provide the broadcast stream on
>> channel 3 or 4 and let the TV deal with it.
>>     
>
> If you mean a cable STV outputs ATSC, just like it would be received off the 
> air? I don't think so. Those I have seen output baseband video as composite, 
> S-Video or component, or RF modulated as NTSC.
>
> ATSC modulators are still expensive, much more than the entire STB, and cable 
> operators are cheap.
>
>   
>> The TV should not know any difference between live OTA, live cable, and
>> a playback of a recording from Myth...
>>     
>
> Most of us use the DVI, HDMI or VGA connector to connect the frontend to the 
> TV set, and nobody I am aware of outputs ATSC from their frontend.
>
> No TV set I am aware can accept ATSC as anything other than RF.
> _______________________________________________
>
>   
Take OTA for example. The best picture I have ever seen on any TV was 
from an antenna connected directly into a coax input of an HD TV. 
Stunning, crystal clear with a visible depth to the picture.

I guess it is not possible to capture _exactly_ what an antenna delivers 
(ATSC - RF?) and then send it back out on the coax at a later date... I 
suppose what I am glossing over is the role that the tuner plays to pick 
out just one channel and I suppose that also alters the signal such that 
it can't just be "put back on the wire" later.

It just seems such a waste to not be able to use the tuner built into 
the TV.

Thanks for all the replies. I think I get it now.

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 Jim Morton