A (stupid) PAL XL2 question

[Nick Hiltgen]

Or Questions...

IF a DV tape can only hold 720x480, Do Pal cameras compress both horizontally and vertically? Also if it's 576 lines of progressive horizontel resolution, would it then still be 960 and 720 lines of vertical resolution, or something different in order to get an accurate pixel count for 16:9 and 4:3 something like 1150 and 850 or is it still the same?

thanks
Nick

[Chris Hurd]

It's the same throughput whether it's NTSC or PAL. PAL is higher resolution, but at a slower frame rate. The data rate is the same either way.

[Patrick King]

Chris,

When you point it out like that, why aren't most of us using PAL cameras then in order to capture at higher resolution?

Obviously the lower frame rate is still 'acceptable'. And according to my Vegas5 manual, I can import PAL and export to NTSC if I'm willing to render.

Are there other big disadvantages to using a PAL camera stateside given that software can compensate for the PAL/NTSC system differences? Does rendering to NTSC negate the inherently better PAL resolution? Are the render times for this horendous?

[Russell Newquist]

Because American TV sets can't display PAL - they only display NTSC format. European sets are the opposite.

It has been, in fact, quite common for people shooting video with the intent to go to film to shoot on PAL camereas for some time, but if you're shooting for television it's much better to just shoot in the format it'll eventually be broadcast in.

[Chris Hurd]

Patrick

I think there are many people who wonder why the U.S. is still NTSC.

PAL cameras aren't as common over here because the millions of existing NTSC monitors aren't PAL compatible -- PAL's 50i frame rate flicker can be difficult to watch in a room lit by flourescents cycling at 60 times per second -- all of our legacy video is all NTSC -- it's more difficult to buy PAL gear in the U.S. -- there are quite a few reasons!

[Barry Green]

<<<-- Originally posted by Nick Hiltgen : Or Questions...

IF a DV tape can only hold 720x480, -->>>

DV Tape is merely a magnetic media, and it can hold practically anything you can write on it. NTSC DV data is 720x480, PAL DV data is 720x576, and DV tape is used in HDV formats so in HDV you can put 1280x720 and 1440x1080 on DV tape. So the tape is irrelevant to the discussion.

The "DV" video standard is what you're referring to, and in DV all formats run at 25 megabits per second. NTSC uses 720x480 at 30 "frames" per second, whereas PAL gets higher spatial resolution (720x576) at lower temporal resolution (25 "frames" per second). The different specs cancel each other out, and the net data rate stays at 25 megabits per second.

[Colin Barrett]

Here in Europe over the last 10 years or so it's increasingly common to find domestic TV receivers and VHS players to be able to process NTSC signals in addition to the PAL standard. I recently connected a friend's NTSC camcorder to my Hitachi PAL TV and it was able to display video and audio, albeit in a "pseudo PAL" mode. Same with my VHS player (yes - I still have a VHS due to the many hundreds of legacy tapes dating from the mid-70s!) - it will play back my NTSC dupes quite happily.

The question of why we're not all using PAL now is simple (as Chris implied) - namely that we're dealing with the matter of huge scale. North America is a big, big market.

Still, one day a new common standard will render PAL and NTSC (and SECAM) obsolete anyhow.

Colin

[Patrick King]

<<<-- Originally posted by Barry Green: The "DV" video standard is what you're referring to, and in DV all formats run at 25 megabits per second. NTSC uses 720x480 at 30 "frames" per second, whereas PAL gets higher spatial resolution (720x576) at lower temporal resolution (25 "frames" per second). The different specs cancel each other out, and the net data rate stays at 25 megabits per second. -->>>

Barry, thanks for writing very clearly something I already knew but didn't recall (it seems the more numbers, facts and figures I read, the fewer of them stick; grey matter available is inversely proportional to an increasing complex world).

Here is the gist of my question though: If the temporal resolution of 25 frames per second is considered adequate for entertainment viewing of video sources, why wouldn't I want to maximize the spatial resolution to increase image quality?

I'm very familiar with temporal resolution as I have worked on the development of combat flight simulators for my day job. They require sixty frames per second as an absolute minimum and for the size of some of the projection systems used, you can imagine the complexity of the computer database to provide resolution sufficient to make the pilot feel 'he's there'. But we don't require 60 at home (really even 60i is only 30 if you think about it), and 25 is 'good enough' in the rest of the world.

So...isn't using the available DV25 bandwidth for addtional resolution instead of squandering it on un-needed frame refresh a really good thing?

[Dennis Hingsberg]

Hi Patrick,

I live in North America and for the last year have been using a Canon XL1s PAL version for making short films for a couple of reasons:

1) The vertical resolution is 20% higher, but this only mostly matters if you plan to do a 35mm film blow up.

2) The frame rate is 25fps (50i) which is much closer to the frame rate film is shot at (24fps). This is great for 2 reasons: again easy to convert over to 24fps film, and secondly adds somewhat of a "film look" look when converted to NTSC. Note: There are many methods, but one involves converting PAL frames to progressive frames and then performing somewhat of a 3:2 pulldown to fit 30fps / NTSC.

3) 50i PAL shot can be converted to 24p with greater accuracy then trying to go from 60i to 24p.

Before the DVX100 this is what I was doing to make films and still use today, needless to say I will be upgrading to the XL2 as soon as it comes out and my Canon XL1s PAL is for sale should anyone be interested - please just check the classifieds section of this site. The camera is mint and only has 6 hours use on it.

If anyone has any questions about shooting PAL for NTSC I can answer them. I also have huge stills on my website if anyone wants to have a peek - click the image to start the slide show.

Oh yeah, as for rendering times to convert PAL to NTSC it takes me 4 minutes for every 1 minute of video I need to convert on a 2.2GHz Intel Laptop. The results would probably be faster on a desktop.

[Patrick King]

Dennis,

Are you going to purchase the NTSC or PAL version of the XL2?

[Dennis Hingsberg]

Yes I forgot to indicate which way I would be going this time.

Despite the fact I've mastered converting PAL to NTSC and impressed people at film festivals with the results of my conversions and work... I'm putting a little more value in how much time I spend in post and am opting for a camera that will just shoot 24p in camera so I can do more quicker.

It's funny because for years both Sony and Canon were telling people who wanted to make DV films on their prosumer cameras to just shoot on PAL if their need was 24fps. Then BANG out came the DVX100 and they both missed out on that market. Canon is a little late now with their 24p camera and I doubt that Sony will even release one. Sony's going straight to prosumer HD later this year and I will bet my new XL2 that it will not offer 24p.

[Nick Hiltgen]

Barry thanks for the clarification, you're absolutely right, I think I just got ahead of myself in asking the question. I meant DV format... maybe... I think...

SO the resolution for a PAL XL2 will be 576x720 and 576x960? Are PAL pixels just compressed horizontally? Or is it simply that PAL pixels are 1x.93 or something along those lines?

Thanks to everyone for their replies, I owned a pal xl1 but I never worried about resolution until now because of progressive scan.

Nick

[Barry Green]

The resolution for a PAL XL2 will be 720x576. There is no 960x576, all PAL DV is 720x576 regardless.

All DV pixels are non-square. NTSC pixels are taller than they are wide, which is why you can pack 720 of them on a line where theoretically only 640 of them should fit (think about it: 640x480 is a 4:3 ratio, 720x480 is not... 720x480 is actually a 3:2 ratio). NTSC widescreen pixels are wider than they are tall (at about a 1.2:1 ratio). PAL pixels are normally a little wider than they are tall (because a PAL TV set is still 4:3, but 720x576 is not a 4:3 ratio). PAL widescreen pixels are even wider.

Computer pixels are square. Video pixels never are... until you get to HDTV. In HDTV the pixels are square, 1920 x 1080 is a 16:9 ratio, and 1280 x 720 is also 16:9.

[Dan Vance]

Despite the fact I've mastered converting PAL to NTSC and impressed people at film festivals with the results of my conversions and work...

Dennis,
If you've mastered the PAL to NTSC thing, I'd urge you to reconsider the PAL XL2 over the NTSC version. You get better resolution with the PAL version, and you don't have to deal with any 3:2:2:3 pulldown nonsense in editing. You're the perfect type of user who would benefit from the PAL version because you've already been dealing with it in an NTSC environment.
Needless to say, I'm a die-hard PAL advocate:
http://www.colddayinhellthemovie.com/VC25P.htm

[Nick Hiltgen]

Barry

I understand you I think, but does that mean that there will be no 16:9 option on the xl2, I'm guessing no, so does that mean that the camera will then compress the information onto the PAL DV tape? Are you saying that there is no 960x576, like there is no 960x480 (because on tape it is compressed to 720x480) or do you mean that the vertical resolution suffers on widescreen pal because it's still 720x576 only now the 720 must cover a larger space so the image quality suffers. Could this be? Could PAL have something that is worse then NTSC? Someone help my world is falling apart!