25p Vs HDV

N

n0signal

Active member
Hello there.

Forgive my ignorance here but I was just reading a post in one of the other threads, and also been doing some reading after Sony's "announcement" the other day about their proposed HDV camcorder, and I have some issues I'm not clear about.

Someone posted that if the Sony camcorder was released in Europe, that it would have to be 60i/30p because there's no HDTV standard here, or something. But the JVC PD1 was 25p/50p/50i wasn't it? I'm so confused. Also, surely with MPEG2 compression there could never be a true 25 frames per second, because only every 6 frames is a true full frame (called an "i" frame), correct? But also, there was lots of talk on the forum about having to de-interlace the footage, but it's a progressive camcorder right!?

I guess with all this talk of HDV I've become interested in the way the market will go. With Panasonic refusing to play ball and sticking with 25p SD it's going to get pretty damn interesting!!
 
Re: 25p Vs HDV

If the Sony camera is marketed there, I'd expect it to shoot 50i/25p. HDV standards include 50i and 25P, so I am certain that any HDV camera released in Europe will support those frame rates, if for no other reason than that it makes downconverting to PAL so much easier.

JVC released a version of the HD1, but they TOOK OUT THE HIGH-DEF MODE! Can you believe it? So the camera in PAL version doesn't have any sort of high-def, just a 720x576x50p mode.

As far as MPEG2/no 25p, that's not correct. Sure there are likely going to be six pure frames, and the rest are interpolated, but that's only how the compression system works. The camera will capture 25 distinct progressive frames, just like the PAL DVX does. The compression uses an interframe/bi-directional/predictive (IBP) encoding scheme to best maximize the data rate, but it's going to look great. I mean, look at a PAL DVD: in DVD encoding they use MPEG2, with a GOP of maybe 18 frames! Meaning, one "real" frame followed by 17 delta-encoded interpolated frames.

All the hullabaloo about MPEG2 is much ado about nothing, for the most part. I have seen objectionable (and highly objectionable) artifacting from the NTSC JVC HD1, but only on rare occasions and somehow tied to the shutter speed. For the most part, it just looks like HD. I predict the Sony HDV camera will look spectacular, as far as resolution and artifacting go. Whether it will have the color rendition and latitude that the JVC lacks, well, that remains to be seen.
 
Re: 25p Vs HDV

Hey Barry, thanks for the reply. :)

That's cleared a lot of stuff up, but further peaked my interest in the whole HVD thing. I'm gearing myself up (and saving a shed load of money) to get a PAL DVX100A soonish and this marketing jibber-jabber from Sony really has got me wondering if I should hold on. DAMN THEM!!

Was also wondering if I shoulg get an NTSC DVX, because they're cheaper for a start and also I'm moving from the UK to Japan in a year or so, which is NTSC country. Then again, I'll be buying the DVX for filmmaking, not video. meh.
 
Re: 25p Vs HDV

The world of video can change quickly while you're saving. No way to predict what the best course will be for you once you have the cash in place. Count on the Sony HDV costing about $5500 or so, so it'll probably be thousands more than the DVX.

So far, the entirety of the Sony HDV announcement has consisted of a mocked-up plastic carving of what a potential shell of the camera could look like. There is no more information than that currently available. Maybe next month at NAB they'll have some info.

So, keep your eyes peeled, and keep stashing your cash. If you'd have bought a PD150 right before the DVX came out, you'd be kicking yourself right now, right? So let's keep our eyes on what Sony does, and what Canon does, but also keep in mind that you can always get a DVX and have the absolute most magnificent prosumer camera currently available. Not a bad position to be in!
 
Re: 25p Vs HDV

Barry about your prediction regarding the spectacular looking footage regarding resolution and artifacting read my last post in the other thread.. I was at CeBIT and what I saw there (of the supposed to be HDV footage) didn't look that good at all... which is nothing to wonder about if you ask me.. putting 1440 x 1080 into 25mbit/s in realtime is some sort of no-no quality wise if you ask me... ;)
Even if it'll "only" cost 5 grand... why not go with a slightly altered tape format with more mbps... MiniDV data rates are really pretty much outdated if you look at the typical transfer rates of modern computers.
 
Re: 25p Vs HDV

Hmmm 1440 x 1080 is a 4:3 aspect ratio... ??? Are they capturing full height anamorphic on 4:3 chips to create the 16:9?
 
Re: 25p Vs HDV

That's what I first thought, but no, it's 16:9.  It's imaged at 1920 x 1080, then recorded at 1440 x 1080, same as HDCAM does.  It's unstretched/uprezzed to 1920x1080 on playback.
 
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