PAL framerates!

[Jan Crittenden livingston]

[toke lahti] “I can’t help thinking that this was not an accident of poor engineering, but done intentionally.”

Hi Toke,

You are right, it is not poor engineering but rather based on technical reasons and thus, intentional. This has been discussed before as to why not and frankly to bring it up again, to say the same things seems fruitless. There are technical reasons why this is not possible, and just because you do not want to give them merit, does not mean that it is possible. It is vastly more difficult than you may even imagine.

Best,

Jan

Jan Crittenden Livingston
Product Manager, DVCPRO, DVCPRO50, AG-DVX100
Panasonic Broadcast & TV Systems

[Toke]

Jan,
I can imagine quite a lot.
Can you tell me any technical explanation or give me a link to one how can it be harder to build a camera to support 24&25p than 23&25&27 or 22&24&26.

I’d like to have a rational and logical explanation.
Thank you!

[Barry Green]

The explanation I can offer is that you have to keep in mind that 24 is not 24, it’s 23.976. However, 25 *is* 25.000. None of the NTSC frame rates are running at their actual nominal speeds, they’re all slightly different — 30 is 29.97, 24 is 23.976, 48 is 47.952, and 60 is 59.94. But in the PAL camera, the frame rates are exact: 25.000, 50.000, etc. So it’s not a matter of simply reclocking for 25 in the HVX — because in the HVX it would actually record 24.975. That would not be PAL-compliant.

In the Sony and JVC multi-standard cameras, you can’t just swap between 50 and 60, or between 24 and 25. It requires a hard re-boot of the camera, turning the power off and rebooting into an alternate configuration — presumably to bring the other crystal on-line (or whatever needs to happen internally).

Which means the HVX would have to have been designed from the beginning with two crystals and two modes in mind. And it wasn’t. And it’s not a trivial matter of just adding another frame speed, because that would produce a system that’s incompatible with the other country’s television system (i.e., adding 24.000 to the PAL camera would seem easy enough, until you realize that the video shot in that mode wouldn’t be ATSC-compliant — so what good is it?) Or, adding 25 to the US version, as simply adding another frame rate between 24 and 26, would result in a frame rate that wouldn’t be EBU-compliant.

Now — with that said, if Europeans wanted 24.000 (and not 23.976) specifically and solely for film transfer possibilities, well, that would seem possible. It would not make footage that could be used in the US, but you could use it for film transfer. But I’d recommend you request it from http://www.panasonic-broadcast.com‘s forum right away — maybe there’s time to implement it, if they feel like it makes business sense to do so.

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db)

[Lars Wikstrom]

Interesting. I don’t know how tough it would be to have 24p on the Pal system but I did get a degree in sound many years ago which I don’t use to much these days. But, I find things are similar. Audio has 8 bit sound and graphics deal with 8 bits as well. As for sound we delt with harmonics and I noticed that 12 was a frame rate of the camera so I would think that 24 would be a Harmonic frequency of 12 which would make it eaier. But then again I have no clue what goes into building these, I just enjoy being the end user.

So is the Pal version going to offer advanced 25p or other Advanced p’s using the P2 cards? I would think many people who buy this camera are thinking about shooting features and then wanting to transfer to film in case their film is a sucsess.

-Lars

[Toke]

[Barry Green] “But I’d recommend you request it from http://www.panasonic-broadcast.com‘s forum right away”

That’s exactly what everybody’s requesting over there.

These 1000/1001-ntsc framerates clearly explains why there would have to be 2 oscillators for “global” model, but it does not explain why Panny is not offering 24.000fps for European model.

We should also remember that televisions are getting more and more like computers that can replay any framerates. At the same time internet is beginning to be a global distribution channel. So “regional” framerates are slowly fading away.

[Barry Green]

[doka15] “So is the Pal version going to offer advanced 25p or other Advanced p’s using the P2 cards?”

There’s no such thing as “advanced” pulldown when talking about the PAL models, because there is no pulldown. In 25P in 1080 or 480, it’s two fields per frame. In 720 mode, it’s frame-accurate. So PAL doesn’t need to deal with the “24p/24pa” situation we have in the US.

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db)

[Barry Green]

[toke lahti] “We should also remember that televisions are getting more and more like computers that can replay any framerates. At the same time internet is beginning to be a global distribution channel. So “regional” framerates are slowly fading away.”

I wish that were true, but it’s not necessarily so. When I had an HD100 I put it in 25p mode and plugged it into my CRT HDTV — no signal at all. TV wouldn’t even recognize it. And broadcasters in the US have no standard for anything other than regional framerates — the ATSC ensconced 23.976hz, 29.97hz, and 59.94hz, and that’s it. There is no broadcast infrastructure in the US to handle 25hz or 50hz. So programming in the US will continue to originate in those three frame rates, and European broadcasters are going to broadcast 25hz and 50hz to maintain compatibility with the last 50 years’ worth of programming sitting in their libraries.

“regional” framerates aren’t going anywhere, they’ll be with us until UHDTV gets adopted sometime in, oh, 2050 or so.

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db)

[Lars Wikstrom]

Maybe I miss understood the ‘advanced p’ Shooting to a hard drive attached to the HVX it was doing a 24 to 30 conversion on the fly so you were left with duplicated frames to make it NTSC comptable. But with P2 cards you could select, what I thought was called Advanced mode, for it to only capture and store the 24 fps and not store the duplicated frames as it would if you were shooting on the DVX100.

thanks,

-Lars

[Barry Green]

What you’re thinking of is “Native” mode. And yes, the European version should most certainly have Native mode.

Advanced on the DVX was a different type of 24-to-30 conversion, which is something that the PAL version never needed to do. But “Native” on the HVX is a space-saving method on the P2 card, and both European and American versions should support it.

—————–
Get the most from your DVX camera. The DVX Book and DVX DVD are now available at https://www.dvxuser.com/articles/dvxbook/ and at Amazon (https://www.fiftv.com/db)

[Lars Wikstrom]

Ahhh, thank you for the clarification. I though Advanced was Native.

One last question regarding native mode. If you shoot 12 FPS native it lays 12fps to the P2 cards. But, if you shoot 12 FPS to hard drive (normal mode) will it then do a 12 to 30 conversion like 24 to 30 with duplicated frames?

-Lars