[opendtv] Re: Olympics picture quality
- From: Cliff Benham <cbenham@xxxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 19 Aug 2004 23:35:48 -0400
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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