Blu-ray is essentially sex-less, but we still have 24p, 50i and 60i to contend with. My equipment will handle them all as well as 50p and 60p, but I understand at least some US equipment doesn't handle 50i (and presumably 50p).

I have the same question about interlaced. Why is *anything* interlaced anymore? Why didn't that dry up about the same time that the first good color LCD monitors came out?

I've actually had people tell me that the reason for interlaced is to make TV more closely resemble movies. Ummmmmmm .... i've never heard of film being projected interlaced. Not once.

I have the same question about interlaced. Why is *anything* interlaced anymore? This one only requires one word: bandwidth.

Even with the fastest computer, 60p 1920x1080 still sometimes stalls and doesn't play smoothly. Many displays still can't handle it. Interlacing is a way to get the same temporal "feel," but with 1/2 the bandwidth. The original HD specs didn't include 60p because back in the early 1990s even 720p was pushing the limits of what could be done.

Bandwidth is extraordinarily important to satellite operators and Internet streaming sites. Anything that can help them deliver a good looking picture, but only using 1/2 the bandwidth is something that can save a huge amount of money.

Lots of people "hate" interlaced video, but when watching on a display capable of handling interlaced video natively, I have never once seen anything that made me dislike the video or wish I was watching something else.

I see no reason why LCDs can't be made to handle interlace video natively, and I hope that someday they get around to doing this.

why didn't NTSC and PAL simply disappear down the toilet ?"

They did, at least in HD. The frame sizes are the same and it's now referred to as "Region50" or "Region60"

Why we persist with different frame rates is for much the same reason as it has always been. In Region60 shooting at 25fps is problematic when there's any iron ballasted lights in shot or used to illuminate anything in shot. I gave up taking my PAL SD camera to the USA for this reason and a lot of footage I shot in Taiwan is useless for the same reason.

If you want to shoot something that's universal then 23.976 can be played out at 25fps and works just fine in Region60 land as well.

I haven't tested 50p/60p down here but I suspect quite regardless of bandwidth or CPU speed the real issue will still be flicker from lighting. Of course the problem goes away with HF / electronic ballasts but it could be decades if not forever before iron ballasts stop being used.

Bob.

My post got blocked. Let's see. Is fluoros a banned word?

Nope

Well I'll try again.

50 Hz fluoros flicker at 100 Hz, while 60 Hz flicker at 120 Hz.

The highest common factor of 100 and 120 is 20, so we should standardize on 20 frames per second and compel people to walk, not run, to avoid the judder. :)

OK, so if I start selling 25i Blu-rays (1440x1080) worldwide, is there a significant proportion of Blu-ray/TV setups that won't be able to play them properly?

The last time I asked that question the answer was still that I would have to make either 24p or 29.97i Blu-rays for the USA, Japan etc., just like in the DVD world, but I'm not convinced about that. If it's true it still staggers me that HD TVs would be made that couldn't support 25i.

I have the same question about interlaced. Why is *anything* interlaced anymore? Why didn't that dry up about the same time that the first good color LCD monitors came out?

I'd say it's the other way round - progressive looks far more like film. 'i' is definitely a TV thing. Most sports for instance are still shot 'i' because normal progressive looks poo with fast camera movement. I guess we'll get to a point where 60p (and above maybe in the future?) will be the norm, but it won't be any time soon. As John sez....cost will always come into it.

OK, you people in the US of A, anyone care to respond to Nick's question?

Can anyone play 50i on locally bought mainstream TVs and players?

I'd say it's the other way round - progressive looks far more like film.Actually, that is not true, but it is extremely interesting that you say that because it gets right at the heart of why interlaced video was used in the first place, and why it is still used, and why it likely will be used for a long time to come.

There are many reasons why film looks like film (many dozens of threads on this forum alone about that topic), but certainly one of the reasons is that it plays at 24 events per second. This number of events is not quite fast enough to fool your brain into thinking it is seeing real-life motion. Yes, it looks like motion, and you don't perceive individual pictures, but until you see something played at a higher event rate, you don't notice the difference.

However, when you see something played back at 60 events per second, it looks quite different than 24. Suddenly motion is very, very smooth, and you don't notice any "judder" when the camera moves horizontally. That judder is something that happens in your brain, not on the screen, and only happens when the event rate is low.

I am sure you notice that I am using the word "event" rather than "frame" to describe the motion. This is because interlacing provides a way to increase the number of times per second that something new is showed on the screen. Even though only half the information on the screen is updated each 1/60 (or 1/50) of a second, it still gives you that many new "events" per second.

So, the difference between film and traditional video has absolutely nothing to do with progressive vs. interlaced and everything to do with the event rate.

Now there certainly are advantage when editing progressive footage (especially when re-sizing or applying certain fX), but when simply shooting and then watching interlaced vs. progressive, especially if displayed on a monitor or TV that can display interlaced natively, the differences are actually pretty subtle. I can very easily describe the difference between the two major cadences: 24p film and 60i (or 50i) video. By contrast, I find it very, very difficult to describe the difference in viewing 60p video compared to 60i. A little more fluid, perhaps. Some extremely subtle differences in artifacts (viewed at full speed) when viewing a volleyball spiked diagonally across the screen. But on the whole, not anywhere near the huge difference between 24p and 60i.

So, progressive is not the key event-per-second element that gives film its "feel:" its the 24 compared to 60 that makes all the difference.

Johnmeyer is definitely right on the 24 film being what makes it feel like film. We used to have clients who would shoot film at 30fps in order to get clean rotoscopes of animations and such. One of their biggest complaints was that with a nice clean digital film transfer to tape, it looked too much like video. The colorist would have to "dirty" it up a bit to get more of the film texture.

Dave T2

"OK, you people in the US of A, anyone care to respond to Nick's question?"

I just rendered a few minutes of 720-60p video to 1920x1080-50i and made a Blu-ray using tsMuxer. The disk would not play on Sony BDP-BX58 or a Sony BDP-S550 Blu-ray players (US versions). The file plays fine in Windows Media Player and the Blu-ray plays in Cyberlink software player.

25p failed on the hardware players but worked on the software players. It will likely have to be 24p to meet the Blu-ray standard.

Edit: I burned the 50i project in DVD Architect with the same result.

There are several region-free Bluray players available in America that will output 50Hz content converted to 60Hz. If you just have a plain region-free or region 50 BR player, your TV won't be able to play it unless it can scan at 50Hz. Mine won't.

OK, so if I start selling 25i Blu-rays (1440x1080) worldwide, is there a significant proportion of Blu-ray/TV setups that won't be able to play them properly?

There is, indeed. I personally, have ordered the final Harry Potter movie on BD from the UK because the US version only came in 2D, while the British edition came in both 2D and 3D. I had no problem watching either BD on my computer here in the US. But there is no guarantee that a standalone US BD player will play those discs. The advice of making them in 24p is sound since all BD players anywhere are required to support it.

Can anyone play 50i on locally bought mainstream TVs and players?I can play PAL DVDs on my son's Xbox 360 connected to a Samsung LED LCD TV. I'll bet that pretty much any TV that permits direct connection of disk drives or thumb drives (my TV set accepts both) can handle a wide range of frame rates and will easily handle PAL. The bigger issue is the player, and I think players that can directly handle PAL are still the exception.

I had a post 'unaccepted' in Acid forum yesterday - no obvious reason. Maybe a few forum-server hickups.

geoff

Possibly they'll play fine everywhere but USA/Americas ? Like everybody (else ?) now has multi-system TVs routinely.

Maybe just another subtle region-coding method ;-)

geoff