[opendtv] Re: Finally anamorphically compressed 480i

  • From: "John Shutt" <shuttj@xxxxxxxxx>
  • To: <opendtv@xxxxxxxxxxxxx>
  • Date: Mon, 24 Jan 2011 08:12:31 -0500
----- Original Message ----- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> 


By contrast, legacy letterboxed SD material is upconverted by PBS
to a full screen 1080i30 frame, and AFD coded to letterbox upon
downconversion to SD 4:3.
Right. But wow, this is simply wrong! If PBS goes to the trouble of making this great upconverted full screen 16:9 image stream, why on earth would stations degrade it so much right at the transmission end? When you could be sending it out anamorphic squeeze 16:9 SD. 



You mean that great upconverted and pillarboxed 4:3?
For SD channels, It is better to send everything out as 4:3 with some material full screen and some material letterboxed (and AFD encoded.) Full screen 4:3 material (including downconverted center cut material originally sent via an HD pillarbox) gets full horizontal resolution, and the AFD code lets 16:9 displays automatically zoom the letterboxed image to fill the screen.
If we did things the way you suggested, then all full screen SD material would lose 25% of their horizontal resolution, and full screen still makes up the majority of SD legacy programming.
And as I tried to explain before, PBS is not our sole source of programming. It is our sole source of HD programming, but accounts for about 50% of the programming on just one of our three subchannels. The other 50% of one subchannel, and nearly 100% of subchannels 2 and 3, come from SD sources.
Oh, and here's another bit of trivia for you. Universal Sports, transmitted as a subchannel from NBC O&Os, has this really nasty habit of NOT centering their postage stamp images, when they transmit 16:9. How annoying is that? Zooming in doesn't work right. And many or most of the foreign postage stamp shows, which come with subtitles, have a nasty habit of putting some or all of the subtitles in the bottom black bar. How annoying is that? Zoom in and the subtitles disappear.
Not being tethered, you may not know this, but what you have described is precisely how almost 100% of SD cable channels are presented. The programming may be letterboxed, but the channel bug, including those animated "mini promo" bugs, fill the screen to the bottom. If, when viewing on a 16:9 monitor, you zoom, you will cut off half the logo, and you will cut off the 4:3 programming (in my experience about 50-50 on the channels I watch.) I had an almost ideal setup when I had my Philips 16:10 television. When zoomed, it still left a letter letterboxing on top and bottom of the screen, and you could scroll the zoom up or down. I would zoom it, and scroll the zoom window down until the top of the letterbox was on the top of the screen. Then the logos were still visible, identifying graphics on 4:3 programming were visible, and most of what was at the top of the screen that was lost was mot missed.
With my 16:9 Sylvania, I lose too much information so I leave it on pillar box for SD channels. Now, if my television would respond to the AFD codes being broadcast, it would automatically zoom for letterboxed material, and pillarbox 4:3 material. But it doesn't know that AFD exists.
The only exception I know of (there may be others but I don't subscribe to all of the tiers) is Fox News Channel. Fox News went to all letterboxed all the time on SD cable channels. Even here, though, they didn't go to 480i 16:9, they went letterboxed 4:3.
John 


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