Exactly and is also one of the reasons I leave the HDR's screen ratio to "16:9 - Widescreen TV" but the Display Format set to "14:9 Pillar Box" since I can't abide the "Fattyvision" that results from the latter being set to "Auto" when normal 4:3 programs are being broadcast.

Since the HDR's "Auto" simply stretches the horizontal, this seems to be a good compromise (with my setup) when viewing 4:3 output since 16:9 transmissions are left alone and the Humax doesn't have a sensible "Smart" option... (since the HDR's output is locked at 1080i, the Sony TV doesn't try and switch)


I would agree...

Colin

thanks for that
HD is an oblong pixel format 1440x1080 just like SD 720 x576
marvellous

Until someone starts making oblong pixel screens there's always going to be scaling

Anyone know if the HDMI output of a Freesat box in 1080 mode is 1440 oblong pixels or do they upscale to 1920 square ones?

Same for 576 line HDMI modes do they output 720 oblong pixels or 1024 square ones

The KDL32W4000 is 1920 x 1080

I haven't noticed this at all and I would go as far as to say that the HD quality from BBC HD is as perfect as it can be on my setup. (to my/our eyes anyway)

Lightsensor=on
Backlight=2
Contrast=60
Brightness=50
Colour=50
Colour Temperature=Warm 2
Sharpness=3
Noise Reduction=Medium
MPEG Noise Reduction=Medium
(both the other features are off - live colour etc)

Colin

I'm rather puzzled by this assertion?


If this IS the case, why then don't black side bars appear permanently on all BBC HD transmissions? (since when locked at a 1080i i/p, this Sony is showing its native resolution of 1920x1080) If the BBC HD's pictures were being transmitted in 4:3 (1440x1080) and not 16:9 (1920x1080) then this would result in a filled screen showing as "Fattyvision"! Which it doesn't and therefore I must assume it is NOT being transmitted in 1440x1080...

(when a normal 4:3 picture is being transmitted, with the way I have it setup, black bars appear at either size and the picture proportions are correct as opposed to distorted in one direction - this is with a normal SD transmission of course)
Last edited by CPN : 01-02-2009 at 17:23

By a coincidence I asked just this in this thread

http://www.digitalspy.co.uk/forums/s...0#post30512840

http://www.digitalspy.co.uk/forums/s...8&postcount=33

answered here

http://www.digitalspy.co.uk/forums/s...0&postcount=36

By a coincidence I asked just this in this thread

http://www.digitalspy.co.uk/forums/s...0#post30512840

http://www.digitalspy.co.uk/forums/s...8&postcount=33

answered here

http://www.digitalspy.co.uk/forums/s...0&postcount=36

Incidentally the pixels are not square or rectangular but are just pixels of a specific colour (usually 256 variations of Red, Blue and Green giving around 64 million colours). It's the pixel aspect ratio that you output it at determines it's shape, it's true that the particular pixel aspect ratio is flagged in the transmission. The pixel aspect ratio and the number of pixels that determines the picture aspect ratio.

thanks
synchronicity

well I thought if they were broadcasting 1440 they might at least use a 1440x1080 camera for source instead it's been compressed from 1920
so that's one level of fuzziness

Agree- whether the pixels appear on screen as wide or square is determined by a flag somewhere or a button on the remote

So - is the HDMI link running at 1440 or 1920 ?
i.e as transmitted or upscaled

I dont know that upscaling from 1440 to 1920 using a digital filter is a doddle !
more like another place for the machine to guess what should be appearing to our eyes

The pixels on your screen can't change shape being a physical object, they are a fixed size and shape. eg square for a 16:9 1920 x 1080 display.

Point 1 at some stage the 1440 horizontal pixels has to be mapped to 1920 pixels to appear on your 1920 x 1080 screen. By the same argument a 1440 x 1080 1080i transmission on a 1368 x 768 screen would have a lot of the picture missing. It does not of course as the TV (or external scaler) scales down to 1368 x 768 pixels

Point 2 the SD picture still has 1920 x 1080 pixels it's just that the pixels outside the 4:3 aspect ratio are black and you can't see them

Interesting

The pixels on the display are square (usually - maybe not for plasma) but the data for each pixel ( which I also call pixels?) is for a space whose width can be determined be determined by the system (widescreen flag?) so can cover one display pixel or one plus a bit more - which means the next transmitted pixel would cover the remains of that display pixel and maybe all of the next one.

How do we do diagrams?

Certainly different to my setup - Thanks I'll give yours a go and see if there's an improvement - (mind you it only happened once in blue moon!)

You are forgetting the fundamental point. No matter how wide the pixel colour information is supposed to be there is only 1440 items of pixel colour transmitted for each line and 1920 is required for a full HD display. You can't have half a pixel (or any other fraction), a pixel can only be one colour in one frame of video. You are correct in saying the colour info can be used for more than screen pixel but only in whole numbers. For example if you used the single pixel data from the transmission for 2 real pixels you would have 2880 not 1920. Also remember the same data has to be used to generate a HD picture on a display having only 1368 pixels (or thereabouts) on a line

It's the same for a plasma it's fundamental maths to make a 16:9 picture using 1920 x 1080 rectangular pixels they have to be square. Any other shape would not give a 16:9 aspect ratio picture
Last edited by grahamlthompson : 02-02-2009 at 09:45

If someone was to design a 1440x1080 screen with oblong pixels that would tie up exactly with the transmission

Problem is that isn't one of the two HD specs 1440x1080 or 1280 x720

How do the broadcasters get away with calling 1440x 1080 as HD

What's to 'get away with'? - there's no fixed resolution for HD, just that it has to exceed a certain resolution.

Isn't the 1440 x 1080 something to do with the stream being transmitted as interlaced- I think that the frames are somehow moved slightly so your eyes actually 'see' 1920 x 1080, however that could be nonsense.

Interlaced simply means the frame is built in 2 passes (odd and even lines) so half the picture is slightly later in time producing a slight distortion for fast moving objects.

Yes, but all interlaced HD video is 1440 x 1080, so this is not some big con on the viewer as 2steps is seeming to make out, it is an industry standard. The only alternative (as they do in the U.S.) would be to transmit at progressive 1280 x 720 60fps. Transmitting progressive 1920 x 1080 at 60fps would take up far too much bandwidth.

Actually the new wisdom on the subject is that 1080p50 is actually just as efficient in terms of bandwidth for encoding as 1080i25 because interlace by its very nature is a messy process. The problem that exists for decoders is that it requires significantly more bandwidth when uncompressed and is more difficult to process. No current decoders can process this format but some new silicon is currently being worked on by the chip designers.

In fact in theory 1080p300 super-long-GOP could produce lovely pictures with very little extra broadcast bandwidth because the difference between each frame to be encoded is so very small. However, before you get all excited no consumer device is currently suitable to handle this format.

The old resolution vs data argument

1280x720at 50 fps = 46.08Mpixels per sec
1440x1080 at 25fps = 38.88Mpps
1920x1080 at 25fps = 51.84Mpps

25fps being interlaced allegedly

However as it's digitally compressed, far less data is transmitted, simplistically just differences from the previous frame

I dont think it is interlaced over the air as when I loose a piece of digital data due to neighbours lawnmower a 16x16 block disappears.

As far as I can tell the box takes uninterlaced data and builds a page from it. The box then supplies interlaced data to the display if required, and upscales it as required

How's that

I should have said

Everyone is going for 1920 x1080 displays thinking that exactly matches the HD 1920x1080 spec, but the broadcasters are only transmitting 1440 x1080 and relying on the quality of upscalers to drive the 1920x1080 display.
The broadcasters already having somehow downscaled from 1920x1080 cameras to 1440x1080.
Sounds like a mess

I'd have preferred they transmitted 1920x1080 and used slightly more compression. At least the pixels would have lined up through the process.

I'd still like to line it up against a good analogue set with an excellent signal and check out something with high background movement like football. No point though, digital is here!

From looking on the net a lot of HD cameras seem to record in 1440 x 1080 interlaced.

I spotted that too - I had a feeling they were all 4:3 rather than 16:9, but not too well up on it

I think the whole point about HD is that it is widescreen no? I also noted that many of the HD cameras seem capable of doing 1080i (1440 x 1080) and 720p (1280 x 720) at 60fps, but not 1080p. Are these the 'normal' HD cameras used by TV studios, and only the really expensive ones used by film studios can actually do 1080p (1920 x 1080)?

Yes, jzee, I noticed this as well - that HD video cameras tend to have 1440x1080 capture resolution. It can not be purely co-incidental that this is also some broadcast resolution too. Although, HD video camera discussions goes on to talk about rectangular and square pixels - I can not see how that relates to encoding and broadcasting...

I suspect that the HD cameras are using 1440x1080 because they are limited by the hardware (chipsets). Just like early LCD and Plasma HDTV sets have the weird 1368x768p native resolution rather than 720p because of the chipsets of the display technology... So maybe this is the same reason - that broadcasters are sending 1440x1080 because of the hardware limitation of their encoders..?

No HD display requires interlaced signals (it's a hang over from CRT) a complete frame is sent in one scan. They are all essentially progressive devices. It's the data in a picture frame that is either generated from an interlaced or progressive source before being sent to the display in a progressive frame scan.