[opendtv] Re: Case for 720p60
- From: Craig Birkmaier <craig@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Tue, 20 Apr 2010 07:37:03 -0400
At 11:09 AM -0500 4/19/10, Manfredi, Albert E wrote:
Craig Birkmaier wrote:
What is lacking here is any discussion of the fact that most folks
are still watching, and most stations are still broadcasting
interlaced SDTV...
In ATSC-land, where there are no MPEG-2 MP at ML restrictions, in
principle at least, broadcasters could begin to transmit SDTV as
480p24 or 480p60. So why don't they?
The only 480p format that could be used is square pixel 640 x 480
with a 4:3 aspect ratio. The ATSC does not support 854 x 480p or
704/720x480p. These formats are supported by MPEG-2 at various
levels, but there is no guarantee that all ATSC receivers will
display them, so broadcasters do not use them.
One of the NBC4 subchannels is Universal Sports, now using 480i. It
probably doesn't make sense to try using 480p24 for sports, so they
would have to use 480p60. If it's true that MPEG-2 compression is so
much more efficient in progressive mode, are the advocates of
progressive saying that the US subchannel could be transmitted as
480p60 over the same ~2.5 Mb/s channel now used for 480i?
Sure, but only using ATSC approved formats as described above.
Regards
Craig
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