HD pixels aspect ratio

[Skylab001]

Does anybody know if the PAL and NTSC Pixel aspect ratios carry over to HD? I'm able to play both formats just fine on my HD set so now I'm curious. I know that my scaler is taking care of the PAL-->>NTSC conversion, but it seems that with HD, pixels should be square since I've noticed all the HD panels are gaining uniformity towards 1366x768 pixels, whether it is a US bought set or a euro bought set. So are the HD pixels square or do they have some other aspect ratio I'm not aware of?

[tlatosmd]

As HD will be a genuinely digital format and pixel aspect ratios are an old analogue malus, I'd be hopeful that HD will be square.

[mattias]

pixel aspect ratio is a digital thing. it has nothing to do with analog systems. different hd formats have different ratios. many of them are square, but hdcam isn't though, for example.

/matt

[Skylab001]

different hd formats have different ratios. many of them are square

do you know which of them are square? Are say 720P and 1080i square pixels??

What got me wondering is that if HD tv's and such are square pixels then those machine vision cameras with square pixels look really good if you are using them with a WP and eventually want to use them for HD stuff......the only problem is, in order to view your material now and on an SD set you would have to tweak the image to get the pixel aspect ratio right.

[tlatosmd]

pixel aspect ratio is a digital thing.

Yes, but it only exists because analogue TV pixels aren't square. No need for non-rational non-square pixels if you make a new standard based on advanced technology that's newer by about 70-80 years.

[mattias]

do you know which of them are square? Are say 720P and 1080i square pixels??

i'm talking about formats as in storage formats. there are both square and non square formats in both 720p and 1080i. hdcam is the only non square format i know of off the top of my head, but i'm sure there are others. i can even create one myself right now: 793x1080. that wasn't hard, was it? ;-)

pixel aspect ratio is a digital thing.

Yes, but it only exists because analogue TV pixels aren't square.

wrong. tv's don't have pixels and there are several digital video formats that use square pixels, i.e. 640x480 and 768x576, and some like svcd that use really rectangular ones like 480x576. it's all about the bandwidth available and it's always a tradeoff against compression.

/matt

[tlatosmd]

I'd be *very* surprised if TVs wouldn't have pixels Mattias. Or do you prefer to call it a raster or dot matrix?

After all, TV resolutions are mostly measured in lines. But if we only had lines as horizontal dimension, all we'd see would really be horizontal lines only. Thus, we need a vertical resolution as well, resulting in actual pixels, not only lines.

We've had electronical pixels like that ever since the pre-WWI invention of radiofax (aka Bildtelegraphie), maybe even earlier by the telautograph. Radiofax was television's important predecessor in being an electronical picture signal transmitter by using pixels.

[Janne]

I'd be *very* surprised if TVs wouldn't have pixels Mattias. Or do you prefer to call it a raster or dot matrix?

Let's not confuse RGB raster used in analog tv with pixels used in digital imaging.

[mattias]

I'd be *very* surprised if TVs wouldn't have pixels Mattias. Or do you prefer to call it a raster or dot matrix?

stop confusing yourself. that has even less to do with the rectangular pixels of dv video.

/matt

[tlatosmd]

I'm not confusing myself, I'm looking for the magic synonym to make you understand. Anyway Janne, we're not talking about RGB rasters here, radiofax and telautograph were both b/w.

All these signals *have* to be rasterized aka pixelized in order to transmit image data electronically.

[mattias]

to make you understand.

haha, that's the funniest thing somebody's written on this board in quite a while. thanks.

/matt