[opendtv] Pan-scan-zoom (was: 70th Anniversary Blu-ray and standard DVDs of the Wizard of Oz)
- From: "Stessen, Jeroen" <jeroen.stessen@xxxxxxxxxxx>
- To: "opendtv@xxxxxxxxxxxxx" <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 8 Oct 2009 09:49:02 +0200
Hello,
Kilroy Hughes wrote that every source should be transmitted as-is, and the
receiver should render it according to the capabilities of the display.
I like the logic of his arguments. I would like to add one component, as
I have proposed in patent US20040130664. Once it occurred to me that ATSC
assumes that HD sources will be rendered on SD displays by down-sampling
the entire image. The composition is preserved (unless the display is 4:3,
of course), but the high resolution is lost. I was thinking that the whole
purpose of HDTV is to put meaningful information in the details, and that
these details are visible because of the larger displays and wide viewing
angle. In other words: HD cameras can capture wider scenes, whereas SD
cameras must sooner zoom in on the details. An original SD production will
look different from a down-sampled HD production. This goes further than the
cropping that occurs in pan-and-scan. Therefore I invented "pan-scan-zoom",
where the source provides some metadata about the area of interest, whose
details should be preserved. The SD receiver can (dynamically) zoom in on
the details, instead of down-sampling the whole image. It is like having
several virtual SD cameras on the scene. A method exists for down-sampling
with a variable ratio and automatically adapting anti-aliasing filtering.
It is explained in patents US5892695 and US6963890, and in the PhD thesis
of Ad van den Enden (ISBN 9066746505). That is a solved problem.
I would very much like to contribute my idea for display framing to a
"standard for multi-standard". It is useful for small displays, far away
displays, or even bad eyesight.
PS, interlace is a form of "super-resolution", it can be your friend. ;-)
Groeten,
-- Jeroen
Jeroen H. Stessen
Specialist Picture Quality
Philips Consumer Lifestyle
Advanced Technology (Eindhoven)
High Tech Campus 37 - room 8.042
5656 AE Eindhoven - Nederland
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]
> On Behalf Of Kilroy Hughes
> Sent: Wednesday, October 07, 2009 17:24
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: 70th Anniversary Blu-ray and standard DVDs of the
> Wizard of Oz
>
> I know you share genetic material with TV sets and see the problem as
> adapting different content aspect ratios and frame rates to whatever the
> most popular sets like, but I want to share with you the pain I live in
> the world of "three screens and a cloud".
>
> In my world, not only is content all over the map, with more combinations
> of picture shape, resolution, and frame rate than broadcast (but
> thankfully less interlace and non-square samples) ... but devices and
> viewing conditions are all over the map.
>
> The architecture that works best is encoding the actual picture height and
> width and frame rate, and making the decode/display rendering device adapt
> to its current display circumstances. That means you might want to watch
> a 2.35AR movie on your iPod with a 1.5AR screen "center cut" because of
> the small screen, but when you plug it into a TV connection going to a
> 1.78AR display using 1.78AR signal format you might tell your pod to
> letter box it with common sides or a slight side crop. If you had a built
> in display that was 2.35AR you could display full screen/wide screen, but
> most displays don't support wire formats that will take a 2.35AR signal,
> so you have to pad to a 1.33 or 1.78 frame.
>
> The basic architecture that works is to encode the content with its
> original source characteristics ... don't hide 24p content in 60i encoding
> (e.g. Blu-ray vs. DVD), and don't hide 1.33, 1.85 - 2.35AR movies in
> 1.78AR encoded frames. Then the device doing the decoding has all the
> information it needs to frame the content for a directly connected
> display, or a wire format that restricts the output options allowed for an
> external display. In my world, we have to assume the same content file
> will be viewed on lots of different devices and displays, so there's no
> option to encode it as though every display is a 16:9 TV and let the
> others suck (the Blu-ray AR problem: Blu-ray is locked to 16:9. DVD was
> smarter because it was designed to handle a mixed 4:3 and 16:9 TV world
> with adaptive framing in the device).
>
> We are going through a painful transition where there are conflicting
> distribution architectures resulting in both rending devices and displays
> fighting to control picture framing and refresh, resulting in postage
> stamp pictures surrounded by letter boxes and pillar boxes and other
> nonsense. Happily, the frame rate part of the problem is underway with
> most modern displays supporting 24P wire formats and many even have a
> "leave it alone" setting to avoid scaling up the image and cropping the
> edges off to simulate a cathode ray tube with a bad power supply.
> Interlace encoding is fading into the sunset very slowly along with the
> dinosaurs. Now we need to make progress on picture framing in a way that
> works in a world with an increasing variety of video devices, where the
> display framing is done by the decoding device with accurate information
> about the encoded picture and whatever wire format it might be currently
> connected to (or not, with direct display control such as internal or
> VGA multisync).
>
> Kilroy
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