[opendtv] Re: Olympics picture quality
- From: Ron Economos <k6mpg@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Fri, 20 Aug 2004 16:17:24 -0700
On AVSForum, an NBC employee states that the affiliate HD feed
("Skypath") is ~26 Mbps.
http://www.avsforum.com/avs-vb/showthread.php?postid=4218233#post4218233
In the next post, it's stated that the satellite transponder is 28.755 Msps
at 2/3 FEC and 8PSK for a payload rate of 53 Mbps. He further states
that the feed is two streams, East coast and West coast (which would
agree with the ~26 Mbps number).
Can you confirm or deny this information? Also, what satellite is the
NBC affiliate HD feed on?
Ron
Dave Robertson wrote:
> > Oh, I should have pointed out in my previous post: The spots
> > come down in the same path they always have for analog.
> >
> > I suspect that part of the delay is integrating the feeds
> > with the HDTV "spot."
>
> Huh?
>
> Here's how it looks at the affiliate (non-O&O) end. The SD network feeds
> come in MCPC muxs on AMC-1. There are three of these muxs with Eastern,
> Central, Mountain and Pacific delays plus various occasional feeds etc.
>
> The HD feed comes as a single carrier at 45mbps (plus overhead), there is
> only one feed. For the Olympics the HD feed is a completely separate
> transmission from the SD network feed, edited and delayed 24 hours. It runs
> it's length (3 hours or so) then repeats until a new show starts the next
> day. There are local avails but it is seamless so an affliliate without HD
> insertion capability can pass it through.
>
> Dave Robertson
> Senior Operations Engineer
> KTUU-TV (NBC)
> 907.762.9579
>
> > ------------------------------
> >
> > From: "John Willkie" <johnwillkie@xxxxxxxxxx>
> > Subject: [opendtv] Re: Olympics picture quality
> > Date: Thu, 19 Aug 2004 21:13:01 -0700
> >
> > Oh, I should have pointed out in my previous post: The spots
> > come down in the same path they always have for analog.
> >
> > I suspect that part of the delay is integrating the feeds
> > with the HDTV "spot."
> >
> > John Willkie
> >
> > -----Original Message-----
> > From: opendtv-bounce@xxxxxxxxxxxxx
> > [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Cliff Benham
> > Sent: Thursday, August 19, 2004 8:36 PM
> > To: opendtv@xxxxxxxxxxxxx
> > Subject: [opendtv] Re: Olympics picture quality
> >
> >
> > Why are the NBC NTSC and HD feeds different? There is usually a half
> > hour difference between them.
> > Terry Harvey wrote:
> >
> > >But are the NBC commercial inserts coming from Athens?
> > >
> > >It seems to me that the MPEG-2 video is going through three
> > encode-decode
> > >cycles:
> > >
> > >Encode Athens, decode/encode New York, decode/encode
> > affiliate, decode
> > >consumer.
> > >
> > >Even at two cycles at 45Mb/s coupled with an 18Mb/s cycle
> > there will be
> > >sufficient loss to give MPEG blocking when there is
> > sufficient motion in
> > >the picture (eg. swinging Olympic logo).
> > >
> > >I don't think NBC New York is passing the video through from
> > Athens without
> > >decoding.
> > >
> > >Terry Harvey
> > >
> > >
> > >
> > >At 01:56 PM 8/19/2004 -0700, John Willkie wrote:
> > >
> > >
> > >>During the Olympics, NBC is being run out of Athens.
> > Indeed, in the case
> > of
> > >>o&o's, the local station is being switched out of Athens.
> > >>
> > >>All the nets use 45Mb/sec contribution feeds, save Fox
> > (when their stream
> > >>switcher goes on line) which will be using 19.29 Mb/sec
> > transmission feed
> > to
> > >>affiliates.
> > >>
> > >>John Willkie
> > >>
> > >>-----Original Message-----
> > >>From: opendtv-bounce@xxxxxxxxxxxxx
> > >>[mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of tjharvey@xxxxxxx
> > >>Sent: Thursday, August 19, 2004 10:58 AM
> > >>To: opendtv@xxxxxxxxxxxxx; opendtv@xxxxxxxxxxxxx
> > >>Subject: [opendtv] Re: Olympics picture quality
> > >>
> > >>
> > >>Doug,
> > >>
> > >>I made mention of this last Sunday. I understand the
> > pictures are incoming
> > >>to NBC affiliates at DS3 rate of 45Mb/s, so the origination
> > encoding from
> > >>New York, or wherever else it is originating from in the US
> > is sending it
> > >>out at 45Mb/s. Affiliates decode and re-encode to 18Mb/s
> > for transmission
> > >>and so there is a generational loss but it should not be
> > all that bad.
> > >>
> > >>My question is how is NBC receiving it at New York? I
> > suspect a third
> > decode
> > >>is occurring before its US distribution to insert
> > commercials. Or else is
> > >>the encode from Athens at a different rate from NBC's DS-3
> > distribution
> > rate
> > >>which necessitates a third decode/ re-encode cycle?
> > >>
> > >>Anyhow, I see the artifacts too. In future the viewer is
> > regularly going
> > to
> > >>have to put up with this as the broadcast 'bean-counters'
> > force limited
> > >>bandwidth. So just live with it and treat it as an
> > interesting special
> > >>effect.
> > >>
> > >>Terry Harvey
> > >>
> > >>
> > >>>From: Doug McDonald <mcdonald@xxxxxxxxxxxx>
> > >>>Date: 2004/08/19 Thu PM 01:03:46 EDT
> > >>>To: opendtv@xxxxxxxxxxxxx
> > >>>Subject: [opendtv] Olympics picture quality
> > >>>
> > >>>Somebody here may well be able to answer my question
> > >>>on the picture quality of the HD Olympics.
> > >>>
> > >>>Sinclair only turned on their true HD here for the
> > >>>Olympics ... it was ready days earlier, but they absolutely
> > >>>refused to let us see some regular HD programming before the
> > >>>Olympics, so that's all I have seen.
> > >>>
> > >>>For static pictures, the quality (1080i) is certainly OK.
> > >>>There seems to be zero detail that my 720p TV can't handle:
> > >>>no change when I adjust the "sharpness" control, except for the
> > >>>local bug, and at CC It saw no more detail on 1080i sets, including
> > >>>the Sony XBR 950 set for "pro" mode, but it looks fine.
> > >>>
> > >>>However, when fast motion starts, such as the flying rings logo
> > >>>they use for replays, all Hell breaks loose: the logo itself
> > >>>breaks up into blocks, and is fuzzy to boot. I see no problem
> > >>>with flying logos on MNF (720p). When they show from-above
> > >>>distant shots of swimmers, the foam breaks up into total pixelated
> > >>>mud.
> > >>>
> > >>>When they show fast gymnastics, when they pan to follow a running
> > >>>gymnast, the background seems to move smoothly, so at least that
> > >>>part of the 50i->60i conversion is passable. BUT ... when the
> > >>>gymnasts have wailing arms or legs ... they actually disappear
> > >>>entirely! No, they don't get blurry ... there is no blur, just
> > >>>background behind where they should be. Well sometimes there is
> > >>>some faint trace or blurry stuff in front of the background,
> > >>>but not much.
> > >>>
> > >>>Clearly the broken up flying logos is a local encoder issue, but
> > >>>what about the foam breakup and the missing arms? Is this local,
> > >>>or due to the 50->60 problem? Has any of you people seen what the
> > >>>un-19.3'd network feed looks like?
> > >>>
> > >>>Overall I would say that both swimming and gymnastics has moments
> > >>>of simply unacceptably bad pictures.
> > >>>
> > >>>Mark Aitken: are you sure that the WICD people have got their
> > >>>encoder set right? Are you using the same brand of encoders
> > >>>at all your 1080i stations?
> > >>>
> > >>>Doug McDonald
>
>
>
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