(gotta love a catchy title ; ) )

Anyway, I noticed in the supposed specs thread that 720p24 was listed as a shooting mode. How is that possible if the camera is supposed to be HDV? Do you guys think it's simply "HDV compatible?"

I'm pretty sure 24p will be handled in HDV the same way it is handled in SD DV, i.e. 3:2 pulldown, which will be removed in post.

1. They are not "supposed" specs. Although there has been no company PR, we were permitted to release the limited specs. If you do a search on us you will find that we have been very involved in HDV since the begining. Our footage was shown at the HD booth last nab.

2. There will be no pull down. TRUE 24P. True the HDV specs do not carry 24P. Sony has to protect it's higher end market (for now anyway)...Therefore this camera is HDV/DV compatible with a new 720 24P 19Mps MTS format.



Regards,


Sean Dinwoodie
Engineer/DP
indietoolbox.com
Chief Engineer - Hollywood Studio Rentals

For All those interested, as select JVC Pro AV Reseller we will begin taking deposits in the next few days at the shop. Please contact us through our website http://www.HollywoodStudioRentals.com or call us at 818-526-0101

<<<-- Originally posted by Sean Dinwoodie : 1. They are not "supposed" specs. Although there has been no company PR, we were permitted to release the limited specs. If you do a search on us you will find that we have been very involved in HDV since the begining. Our footage was shown at the HD booth last nab.

2. There will be no pull down. TRUE 24P. True the HDV specs do not carry 24P. Sony has to protect it's higher end market (for now anyway)...Therefore this camera is HDV/DV compatible with a new 720 24P 19Mps MTS format.-->>>

I wasn't insinuating that the specs you listed were a lie or a guess, only that I don't think they'd be considered "official" until they are released by JVC at NAB.

1) Is there more info available about the 24P, HDV compatible spec yet, or do we have to wait for the cam to be released?

2) Is Sony the sole reason 24p was left out of the original HDV spec?

Well, Sean was very fortunate to have attended a "sneak peek" at the camera, and I seriously doubt that anything he has said is going to conflict with what JVC reveal at its official announcement. I'm just glad he chose to share it with us!

ProHD, a variation on the original HDV spec, because it does 24p.

heath

Heath's right and you've got to remember that 24p wasn't supposed to be part of the DV spec either, and yet there are several DV cameras that do 24p now.

Well, 2 anyway (DVX100A and XL-2). I'm excited about this camera, even if it is 720p. A lot of my friends dig the VariCam a lot, so this could be the VariCam of HDV.

heath

So when this camera is in 24p it is not also in HDV mode?

That may allow JVC to do the audio differently than the MPEG1 audio on the HDV cams.

Yes, HDV 720p24. We have a TON of awesome information:

www.hdvinfo.net

SO CHECK IT OUT! ;-)

heath

It was my understanding that its 24p mode was *not* HDV compatible, that it was instead a newly-developed transport stream, similar to those used by HDV, but outside the HDV specification. I could be wrong on this, and it may be just carrying 24p frames within a 60i or 30P HDV stream, but for reasons elucidated elsewhere, that would not be optimal.

If it's a new format, that would indeed let them expand upon the spec, but it would mean that it may not be supported by editing programs that support HDV. However, I'd vote that they do it "right" anyway, and the editing programs may well adapt quickly -- it should be very similar to HDV, just a different frame rate.

Right, Barry, 24p is a new thing to HDV and it's a variation, ProHD.

heath

I think it's kind of funny that they put "Pro" in the variation and removed "HDV."

EDIT - I'm not knockin' the format; it just seems like a little bit of spin to me.

Doesd anybody have any guesses about what the GOP length might be for 24P? If shorter than 30P, that makes the format even more acceptable to shoot on. I'm still not sure about editing.

None of us know about editing--it may be another year before anyone has anything...

heath

I don't think any special editing software would be needed. All you need is the ability to import the footage and output it in an uncompressed format. If they record 24 real frames per second only then there would be no further processing required.

Sounds like "ProHD" will indeed be a new format, sort of like a DVCAM version of DV was a new format, even though the internals were all basically the same.

I don't know if JVC has announced any specs on the GOP or anything else about the 24P option, other than to say that it's still 19mbps. Even if the GOP is the same length, that's still good news, as it means each frame will get more bits allocated to it than would have happened in HDV 720/30p, so more efficient compression and fewer artifacts.

If the GOP is shorter or longer, that's both good and bad. Shorter GOP means easier/more efficient editing, less impact of dropouts, and less impact of variable-resolution imaging on high-motion, high-frequency changes. However, MPEG compression excels at longer-GOP lengths, that's where the efficiency of the MPEG compression really comes into play, and why HDV on the FX1/Z1 can look so great (especially on relatively static shots) at such a tiny bitrate.

The thing to keep in mind is, the GOP in 720p is already a *lot* shorter than it is in 1080i. In Sony's 1080i version of HDV the GOP is 15 frames, but in JVC's 720p implementation it's already a six-frame GOP. So even if the GOP stays the same for ProHD 720/24p, it'll still be much shorter than the GOP in 1080/60i HDV.

I thought it was still mpeg2-ts, which would require special software, unfortunately. ARGH!

heath