[opendtv] Re: Information on ATSC M/H (MDTV)

  • From: Tom Barry <trbarry@xxxxxxxxxxx>
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Thu, 13 Nov 2008 07:35:05 -0500

John -

416x240 is quite easy to make from 480i without any fancy deinterlacing if you send only 30 frames per second. Do you know if that's what they intend for mobile?

- Tom

John Willkie wrote:
I had some free time today, and I took a look at the October issue of
Broadcast Engineering.

Lo and behold, there's an article by Jay Adrick of Harris and Wayne Bretl of
Zenith on ATSC MDTV.  The article is available on-line
http://broadcastengineering.com/RF/mobile-dtv/index1.html

One tidbit that might be of interest here is the video size: 416 x 240.
They call it 16:9, but the ratio is 1.73333, where 16:9 is 1.77777.  More
accurately, it's somewhere between 15.7 and 15.8 to 19.

The yarn isn't in tremendous detail, but one can learn how the system works
on the transmit side.

I did notice one (presumed) nit:  they refer to the Initial Demonstration of
Validity (IDOV) tests that were performed earlier this year.  The report I
read on May 15 was called the "Independent Demonstration of Validity" tests,
and as one participant told me at NAB: "that's three distinct concepts."
Alas, I and the many other members of this reflector who have read that
report can't talk about it, but "initial" doesn't do it justice.

Also, I thought it was interesting that the article mentioned the h.264
video codec version in the proposed system, but not the version number of
the audio codec.

Only time will tell when or if the candidate standard is released to the
wild.  I have read all sorts of articles on the dates when things should be
finalized, but I've never actually read an article that provides dates that
coincide with the planned dates, so I choose not to mention those.  And,
things could change .

So, who's excited enough to watch MDTV simulcast content in not-quite 16:9,
at much less resolution than is available in HDTV?  And, does your TV have
an IP stack?
By the way, there are several significant proposed features that - at best -
are only alluded to in these articles.  So, this is only a peek behind the
curtain.

John Willkie




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