Side by side vs line by line interlaced

[Tony Reidsma]

While I work out my editing issues, I'm doing some testing on what will work best for viewing on a passive 3D tv.

What is the best quality setting, or is there a difference in quality between side by side vs line by line interlaced?

I only go down the road of interlaced because my client wants me to have an effect that has a kind of picture in picture effect, with the back ground video holding during the duration of the PIP.... anyway, this effect is best pulled off with interlaced, but I don't want to sacrifice image quality.

Thanks,

Tony

[Adam Stanislav]

If the side by side is full width, it is the best because there is no loss of resolution.

Otherwise, both methods lose one half of its resolution, line interlaced loses half of the vertical resolution, side by side loses half of the horizontal resolution.

Now, I have never tested this but, theoretically, the loss of the horizontal resolution is probably worse, in 3D terms, than the loss of half of the vertical resolution. This is because the 3D visual ability comes from the horizontal difference between the two images, and the more of it you preserve, the better the 3D visualization.

Again, I have not tested this, so I am just speculating, but I would venture the guess that the line interlaced would be a preferable solution over half-width side by side, simply because while in either case you are losing half of the resolution in one dimension, the line interlaced method does not lose any 3D information, while the half-width side by side loses one half of the 3D information in addition to losing one half of the resolution.

Again, not tested, just thinking about it and proposing a hypothesis.

Your best bet would be to test both methods and see which one is better.

[Neil Richards]

For Passive 3D theoretically top-bottom would be better than side by side, due to the way the TV's work.

In practice there seems to be little difference - I tried both into a passive TV but honestly couldn't see anything between them. Maybe I should look at it again in more detail.

I was told by a stereographer that the human vision system can cope better with loss of resolution horizontally than vertically i.e. throwing away horizontal info is better than throwing away vertical info. Haven't corroborated this though - anyone know anything more about it?

[Roger Dass]

I've done quite a bit of testing in this area...

My observations were that on passive displays, where polarization changes by alternating rows, top-bottom video is in fact sharper than side-by-side. This is more evident when using minimally compressed video or uncompressed stills.

Ideally, on a 1080p television, each view can be the full 1920 pixels wide, but the max resolvable height is 540 per view. If you use side by side, then you'll limit the horizontal res of the content to 960, and wasting half of the 1080 vertical pixels of the content because the tv will only display 540 for each view anyways.

[Neil Richards]

It's actually a bad situation for passive, because it means any side-by-side material is half-resolution on an active display but quarter resolution on a passive. This was the point I made to a couple of TV engineers from the BBC and Sky at a workshop late last year - transmitting side-by-side is not a good idea for people with passive TV's and they both acknowledged this. Just a pity that all the 3D DVB digital terrestrial TV standards, and youtube, only support side-by-side and have no way to handle top-bottom (or line interlaced), so we're stuck at the moment.

[Roger Dass]

Yeah I agree.

I think this is one of the reasons why MVC is starting to gain traction. This is why I want to support MVC in my iPad3 3D project as well.

[Prech Marton]

Line by line interlaced?

That format cannot be in interlaced format, right?

So, if somebody want smoooth motion, then sidebyside is the way to go.