[opendtv] Re: Blue Ray has competition
- From: Terry Harvey <tjharvey@xxxxxxx>
- To: opendtv@xxxxxxxxxxxxx, "OpenDTV (E-mail)" <opendtv@xxxxxxxxxxxxx>
- Date: Wed, 01 Sep 2004 20:26:08 -0700
Bert,
The problem lies with old NTSC infrastructure which is now coupled with new
component systems in many North American production facilities.
In Europe, where the transition is nearly complete from the camera through
the production switcher through the video server and post production,
non-linear editor etc. etc., it is all component.
In North America, if you look at many facilities you have legacy D-2
(composite) switchers and equipment and a great amount of composite analog
equipment. This equipment is intermingled with component non-linear
editors, servers, VTRs and Digital effects equipment. This means that the
production video is passing through a multitude of encode decode processes.
Current non-adaptive digital comb filter decoders, although pretty good,
are far from perfect. The net result is a washed out image with strange
non-related artifacts lurking in the image.
One of the games we play is "How Many Times Has The Video Gone Through an
NTSC Decode/ Encode Cycle". Here are the rules:
Catch a relatively still image with vertically adjacent high chroma
transitions. When the video has gone through a comb filter decoder, the
adjacent chroma cannot be defined by the multi-line averaging of the
decoder. The result is a thick band probably across four to six lines of
indeterminate color and with what appears to be prominent subcarrier dot
crawl. The width of the band will give a rough idea of how many
decode/re-encode cycles the video has undergone.
I have seen examples on over the air broadcasts where the width of the band
is substantial and hard to define but my guess it went through the
decode/re-encode process about five or six times. I suspect this goes
largely unnoticed because the picture is already soft at this stage.
Terry Harvey
At 03:24 PM 9/1/2004 -0400, Manfredi, Albert E wrote:
>Terry Harvey wrote:
>
> > My point earlier was that you are NOT necessarily watching PAL on
> > Euro displays. Or only one generation through a PAL interface.
> > Most Euro broadcaster's production went component years ago.
>
>Not sure I understand what you're saying, Terry. Even if the
>production went to component analog, the OTA transmission is still
>PAL, no? So any PAL weakness would still show up in the TV set.
>
>Anyway, both here and there, this will soon be ancient history.
>
>Bert
>
>
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