[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: "True", "True" (H)DTV....and the relation to 720/60P Display Syst ems

KA2IQB at aol.com wrote:

> Unfortunately, it's very hard to convert interlaced to non-interlaced images without creating temporal artifacts, so 1080i was included in the ATV standard to allow for a gradual transition from present-day 525-line interlaced technology to DTV. 
> Cordially yours,
> Christopher Bacon

1035i/60 was the first format brought out by the Japanese for the MUSE
transmission system still in use today. At the same time Sony built 
1035i/60 production equipment. This equipment demonstrated HDTV to the
American Broadcasters which in turn lobbied the FCC for transmission of
HDTV signals. This 1035i was later changed into 1080i to incorperate
square pixels. 1080/59.94 was later included to help the transition from 
525/59.94 to 1080/60 along with the rest of the formats in the famous
table 3.   
It's hard to convert live video camera material from interlace to
progressive, it's easy to convert from film that was orignally scanned
progressive. We do it every day without temporal artifacts. We go from
film scanned progressivly at 1080/24fps into a digiscan that creates a
3:2 sequence and makes a 1080i/30fps tape. From that we run it into a
downconverter and strip out the 3 field put the two interlaced fields
together to create the orignal progressive signal at 24fps and then
spatilaly intorplate to our next vertical resolution ie. 625 or 525 add
the 3:2 sequence and were done. We could just as easily make 1920x1080p
or 1280x720p at 24fps. We could add a 3:2 sequence to it and make
60fps.Now for your video camera material ie. News, Game Shows, Sports
your 1280x720p buys you a 720 vertical spatial resolution for your 60fps
frame rate compared with the 540 vertical spatial resolution of
1920x1080i at 60fps.You've got a 74.25Mhz production bandwith slice it
any way you see fit. 

Howard Lukk

  HDTV discussion thread is at http://www.alegria.com/telecine/hdtv.txt
         Thanks to Bill Topazio for support of the TIG in 1997
      TIG subscriber count is 863 on Thu Oct  9 23:17:29 PDT 1997
     mailinglist digest available.... unsubscribe via a message to
        'telecine-request at alegria.com' with Subject: unsubscribe