[mythtv-users] Hauppauge HD PVR (A bit more info for those starved for it)
Robert Kulagowski
rkulagow at gmail.com
Fri Feb 29 20:19:34 UTC 2008
Chris Ribe wrote:
>
>
> > I look forward to the day when more broadcasters actually use higher
> > bitrates... Here, only CW and NBC use such a high bitrate.
> >
> > Mike
>
> Doesn't CBS broadcast in 1080i too? I thought only Fox and ABC used
> 720p?
>
>
> Bitrate, not resolution. For example, here at WCJB-TV in sunny
> Gainesville, Florida, we use our 19.2 Mbits to broadcast 2 program
> streams. One is ABC, which is broadcast at 720p , and one is the CW,
> which is broadcast in a 480i format.
>
> Before these signals leave the building, they are joined together in a
> muxer - a fancy computer that takes one HD-SDI video signal, one SDI
> video signal, and puts out a single SMPTE 310 signal, which is a fancy
> name for baseband ATSC, I believe.
>
> Anyhow, the muxer tries to squeeze as much video quality into the 19.2
> Mbits as it can, and it dynamically reapportions bandwidth between the 2
> program streams. When all is said and done, the CW usually ends up with
> about 5 Mbits and ABC gets about 12.5 Mbits. I honestly do not know
> what happens to the other 1,700,000 bits per second.
>
> The end result is that the CW looks quite good, an ABC does not. Our
> neighbors at WUFT, the University of Florida PBS station, do things a
> little differently. They have 3 program streams, one which is usually
> 1080i and two standard def. The give their HD channel about 14 Mbit and
> squeeze their SD channels into about 2 Mbit apiece.
Since you're a TV/IT engineer, and apparently have something to do with
ABC, can you please look at the "Funky 720p" thread in -dev?
ABC seems to be doing weird things with their ATSC programming, and at
first all of the responders to the thread were in Chicago, but we just
got a datapoint for someone who's down in Texas, so it may be more
prevalent.
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