I hear what your saying, "If it's not in the specification, it's not a bug". IMHO, it's some fishy stuff. It's actually easier to decode 720h rather than 704h. 720h matches the output raster perfectly, while 704h requires that the image is centered in the 720h output raster (or at least you're supposed to). So there's an extra step to decode 704h versus 720h. A decoder that can do 704h but can't do 720h is totally counter-intuitive. It's almost like they deliberately tried to hose it up. The ATSC's take on this is summarized in the candidate specification for Annex A: http://www.atsc.org/standards/cs_documents/CS-TSG-674r1.pdf From the proposed Table A3 "category" for 720h:B: These formats were not included in the original Table 3 of Annex A of A/53, *but have been in use by broadcasters for several years without reported complaint*.
These formats are included in Table 3 of ANSI/SCTE 43 2005. Here's the link for the SCTE reference: http://www.scte.org/documents/pdf/ANSISCTE432005.pdf Here in the Bay Area, some of the DTV stations are using 720h. KCSM-DT is 720x480 on their main channel and KTSF-DT is 720x480 on both of their simulcast (but different Chinese dialects) video channels. KQED-DT (the big PBS affiliate) uses 528h on all 3 of their SD channels when the main channel is HD. KKPX-DT also has a 528h channel in their multiplex. What's the holdup on the candidate specification? Is it political (as you suggested previously), or is it due to the fact that the AFD and bar data specification is still in flux? If the candidate specification is never going to happen, it should be removed from the ATSC website. Ron Mark Schubin wrote:
Just so. TTFN, Mark John Willkie wrote:When doing testing of my PSIP generator recently, my customer found that a very recent Zenith DVR (and at least one other recent STB) couldn't make useof 720 x 480 video. Not only that, but several other issues disappeared when he eliminated 720 x 480 video. IIRC, the Samsung STB had no issues with it, nor did the AutumnWave USB device. John Willkie-----Original Message-----From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Mark Schubin Sent: Thursday, February 15, 2007 7:12 PM To: opendtv@xxxxxxxxxxxxx Subject: [opendtv] Re: Food for thought It was long ago, and it's relevant until ATSC changes the compression constraints. Until that happens, broadcasters need to avoid 720h or risk hitting TVs that can't receive the signals. TTFN, Mark Ron Economos wrote:You've posted that many times. How long ago was that, and is it still relevant? Ron Mark Schubin wrote:During the development of our ATSC DVD recorders at LSI, *we tested all 36 formats* and much more (sub-sampled horizontal resolutions, telecine flags in both 1080i and 720p, QAM, bad PSIP, high BER, etc.).In ATTC's testing, unfortunately, they found two models of DTT receivers that could not handle 720 x 480 imagery at certain frame rates (different rates for the two receivers). 720 is not only in Rec. 601, but it is also divisible by 16. Unfortunately, it's not in the infamous Table 3. TTFN, Mark