I edited a mistake in my first post... just too muddy it up further.

:-)

Learn something everyday:


http://en.wikipedia.org/wiki/DVD-Video

I've never seen anything but 720x480 (and the older 640x480) but it turns out there is a definition for 704x480 as well.

Non square pixels sure are fun. :-)


best regards,
mike

mike_mccue


4 / 3 is 1-1/3

7040 / 5280 is 1-1/3


But that could just be a coincidence. I've never heard of the 10:11 ratio... but that doesn't mean anything except I haven't heard of it.


I don't think he's doing an effective job of explaining pixel aspect ratio in non square pixel systems. I'm not saying I can either.

Just an observation.

best regards,
mike

Pixel ratio's are limited to the map not the territory.  The visual representation not the equation resolving the actual signal.
 
Watch it again and note how he says it is confusing to refer to the plot as anything other than a lollipop graph, they are merely co-ordinates for plotting a completely accurate vector given a known bit depth, given those constraints you can't even be slightly out at any point along the plot without something being completely wrong.
 
It's not even smoothing by interpolation there is only one place a co-ordinate can be in relation to the others at any given moment when the bit depth is known.
 
You see on the oscilloscope the sine wave is identical even after going through the A/D interface D/A process it shows the same sine wave as the straight through. 
 
The whole point of his description is to show that the pixel based assumption you are making is erroneous from the outset.  Once you realise that and stop thinking in terms of pixels then it starts to make sense.

I like green lollipops the best.

drewfx1


I like green lollipops the best.

mmm Lime.
 
Or am I just assuming that from the colour?

It seems like he is describing a world that has passed us by.

Now a days we shoot in digital, we transfer in digital, we edit in digital, we playback in digital, and our display screens are built around clusters of pixels.

It use to be "line", screens and apertures with lots of A to D and D to A transfers.

Now a days thinking about pixels seems entirely appropriate.


I wish I had not made the initial casual and erroneous comment... :-)  Now I am having to actually think.



all the best,
mike

Jonbouy

drewfx1


I like green lollipops the best.

mmm Lime.
 
Or am I just assuming that from the colour?

I think the formula is:
Green_lollipop = Y_lollipop - Cb_lollipop - Cr_lollipop


I'm not sure where the lime quotient comes in.

Put the lime in the coconut.

mike_mccue


It seems like he is describing a world that has passed us by.

Now a days we shoot in digital, we transfer in digital, we edit in digital, we playback in digital, and our display screens are built around clusters of pixels.

It use to be "line", screens and apertures with lots of A to D and D to A transfers.

Now a days thinking about pixels seems entirely appropriate.


I wish I had not made the initial casual and erroneous comment... :-)  Now I am having to actually think.



all the best,
mike

Put it this way, when you type a vector based font on a screen it looks stepped.  Choose a larger size and it looks less stepped.  Because it is vector based and not a bit mapped font you could theoretically blow it up to the size of a billboard and because the vector plot remains constant you see the steps are merely a limitation of the representation and not a product of the actual calculations describing the font.
 
Therefore given an adequate bit-depth the digital signals converted back to analogue as are smooth as the vector plot of a babies bottom.
 
Roughly.
 

I think of bit depth on the Z axis. It defines the color space and light value dynamics rather than spatial resolution

I've seen plenty of vectors in video edit/composit/motion graphics applications but I have never seen vector math used in any digital video distribution formats other than "flash" and "silverlight".

Maybe Blue Ray authoring has some?



best regards,
mike