[mythtv-users] OT: ATSC/QAM Encode to distribute HD over longer runs.

[Roger Heflin]

Chris Ribe wrote:
>> I would think at min you would need something to take a proper ATSC
>> bitstream
>> and use the 8VSB or the cable modulation scheme to modulate it onto a
>> channel,
>> and I would not think that putting that on something like USB would take
>> cost
>> that much to make, so long as the computer was providing the proper
>> bitstream to
>> start with.
> 
> 
> I don't think that an individual USB 8VSB/QAM modulator would be expensive
> to produce.  Neither do I think that any of the software problems involved
> in implementing an ATSC video distribution system are hard.
> 
> I think it is unlikely anybody will start producing and selling the hardware
> cheaply anytime soon.  When you consider the cost of IR repeaters and their
> associated wiring, an 8VSB modulator for each simultaneous channel, and
> hardware that can support realtime encoding of each stream in addition to
> all the other things you would like it to do, the complete system just isn't
> much cheaper than putting a networked set top box at each TV.

There are wireless IR repeaters that do work, I have some of them, and so far 
they have worked reliably-I have not had *ANY* problems with them so long as you 
point them properly.   It mainly stopped me from having to run ethernet to every 
room and buy multiple NTSC set top type boxes to display mythtv (and the set top 
boxes are about 2-3x the price of the wireless IR repeater setup per TV, and the 
set top box I have is SD and <$100).

Most new PC's are capable of this.  On a old 3.2 Ghz P4, I can decode HD and 
re-encode it into SD right now at slightly faster than real time (using 
mencoder-full 1080i).    Given a slightly faster processor (say a single core of 
a 2.6 Ghz core2duo-the 3.2Ghz P4 is equal on speed to a 1.6 Ghz T2060-so a 2.6 
is >50% faster) it should be quite easy to go HD to HD.   Given a quad core it 
should be quite easy to handle at least 1 stream per core.

> 
> Eventually we will see cheap ATSC encoder/modulators, but I don't expect to
> see them soon.  There just isn't a market for them.

I agree that the no one sees a market for them.    Some hobbyist with some RF 
knowledge will probably need to build a simple one before a large company 
figured out that someone would buy it.

Given a bit more time, and with new TV's eventually no longer having NTSC tuners 
(probably a number of years off) that will increase the market as people will 
want a replacement for the current NTSC modulators.


> 
> -chris
> 
> 
> 
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