[mythtv-users] HDHomeRun

Brad Templeton brad+myth at templetons.com
Sat Aug 5 05:51:12 UTC 2006


On Fri, Aug 04, 2006 at 09:55:25PM -0700, WJCarpenter wrote:
> bt> ATSC is not useless for you.  At least in this city, fox, nbc,
> bt> upn/wb and all the independents broadcast SD channels over ATSC.
> 
> Heh, in this area (environs of Seattle), one of the locals uses a
> digital channel to show 24x7 coverage of a (security? traffic?) camera
> of the road leading to the departure area at SeaTac airport.  No
> audio.  Fascinating.

Sure.  If you decide not to do an HD channel (or even not to have an HD channel
all day which is PBS's current approach) you can fit 4 good quality SD channels
on your frequency, and you can fit even more if you let some be lower quality.
Whatever you can fit into 19 megabits.

Right now, all the broadcasters have decided that each channel/subchannel
will remain in exactly the same format all day.  So if it's a 1080i channel,
it's always 1080i, even when showing SD programs, or sports which are better
at 720p.  (Especially right now when only a small fraction of the HD owning
market has 1080 line sets, though this will change.)

Now the SD programs on 1080i do look noticeably better than they do at 480i digital
TV.    That shouldn't be true, but it is.   For letterboxed programs on PBS, this makes
sense, because the program was presumably shot at 480i widescreen, and they
upsample this to 1080i, while at 480i they show it letterbox, droping to about
350 lines.    Perhaps the programs now are being mastered at 480p and seeing them
at 1080i with bob gets us closer to that, while 480i gets us less than that?

Anyway, there are many local channels here that only run 1 or 2 480i channels.
They have no HD content.   After the mandated switch to digital, they might
well start throwing up more of these channels.

Or, what I think would be very interesting would be for local broadcasters
to start selling slots to popular cable channels like CNN, Comedy Central etc.
Those channels would have to live off their commercials, no fees from cable
companies, but they could get wider audiences.


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