[opendtv] Re: Olympics picture quality

What makes you think that the streams coming down from the satellite are
compressed?  And, that they aren't baseband?

Are you sure that there are now "economical" devices in the real world that
will do compressed switching?  Just last week, I was talking the network
engineer behind the first such announced system, and I was told that it
wasn't working yet.

I'm telling you that it's coming directly from Athens, a more extensive
webbing than was done in Atlanta, (I don't know about Sydney), and you
persist with -- appropros of nothing -- legacy thinking.  Got any proof or
evidence?

John Willkie

-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx
[mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of tjharvey@xxxxxxx
Sent: Friday, August 20, 2004 9:05 AM
To: opendtv@xxxxxxxxxxxxx; opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Olympics picture quality



Perhaps you could call what NBC is doing 'transcode'. However, the NBC
affiliates are decoding to uncompressed baseband from the 40Mb/s compression
and re-encoding to 18Mb/s for transmission to the consumer.

We are having to go through the decode/encode cycle at our broadcast
station. However technology is catching up and there are now 'economical'
devices which allow us to seamlessly splice and to insert logos on the
MPEG-2 video without decoding.

I would be curious to find out if NBC is decoding to baseband at New York. I
don't think they would be constricting the feed to the US. I would suspect
that everything incoming to New York for DTV network distribution must be
decoded to pass NBC's DTV network control.

Terry Harvey

>
> From: "John Willkie" <johnwillkie@xxxxxxxxxx>
> Date: 2004/08/20 Fri AM 12:12:44 EDT
> To: <opendtv@xxxxxxxxxxxxx>
> Subject: [opendtv] Re: Olympics picture quality
>
> From what I was told by the CE at an NBC o&o station in a brief telecon
> (we'll have a sit-down after the show is over) the only things coming out
of
> New York is the news.  His station's analog and HDTV feeds are COME
DIRECTLY
> OUT OF ATHENS.  New York is upstream from Athens in this configuration,
not
> downstream.
>
> Here's how I understand it: MPEG-2 elementary streams are encoded in
Athens,
> live, and they're decoded in the MPEG-2 section of digital TV sets in
> millions of homes.
>
> I haven't taken the time to check with the folks I talk to at the network,
> but this is the first time I've heard of a non-CBS network doing something
> like this: controlling stations from remote venues, not the TOC.  Oh,
yeah,
> TOC's control networks (legacy mode) and not stations.
>
> The biggest complaint one hears about this from CBS stations:  "How come
> just the o&o's get this degree of control?"  I've been told -- and not
from
> official CBS folks handling this, who I've talked to more than a few times
> this year on "another" topic -- that all the stations could have this
> technology this year, after the o&o's work out the bugs.
>
> I can't say -- at this point -- that is exactly what NBC is doing.  I will
> know within a week or two of the end of the games.
>
> Distribution and contribution are 45 Mb/sec.  Transmission is 18 Mb/sec.
>
> And, of course, the stations do have to "decode" the 4:2:2 MPEG-2 signals
to
> make them 4:2:0 for transmission.  That's still required.  But, you used
the
> word "decode."  Maybe I'm being pedantic/technical, but I tend to call
that
> "transcoding."  And, since it requires one to throw away bits, of course
> data is lost.
>
> When one takes a DS-3 feed down to baseband, unless I'm missing something,
> one should not assume that a single bit is lost.
>
> John Willkie
>
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx
> [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Terry Harvey
> Sent: Thursday, August 19, 2004 8:01 PM
> To: opendtv@xxxxxxxxxxxxx; opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: Olympics picture quality
>
>
> 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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