JVC 4K Camcorder Announced

[Bart Walczak]

Troy - I guess the decision to use HDMI 1.3a was made because, from what I can tell, this camera has 4 parallel circuits coming out from the ADC that converts analog signal from the sensor, and then the whole pipeline follows from that. This way you can reuse components that were already proven, like encoders and outputs, and R&D costs are most likely significantly reduced.

I presume there is only a single ADC, because JVC has already found out (and the customers also in a hard way) that those chips are a nightmare to calibrate evenly, and any low-light, high-gain shooting scenario would result in a split screen visible differences. Plus the fact, that you can window your sensor to 1080 any way you want suggests that the windowing happens in the ADC, and then only a single pipeline is engaged in encoding, output etc.

If they wanted to employ HDMI 1.4a, they would have to add another separate piece of circuitry to do this. Not that it would not make our lives easier, it would just be more expensive.

[Jim Michael]

Anyone know whether either of the 2 new cameras have genlock?

[Mark Donnell]

I agree that this camcorder sounds wonderful, but I'm concerned about the amount of compression involved. As I recall, full 1080p 60 fps video comes out at 3 Gbs uncompressed. As I understand it, this camera records at 28 Mbs, giving a compression of greater than 100:1. What can we expect with such a high compression rate ?

[Troy Lamont]

I agree that this camcorder sounds wonderful, but I'm concerned about the amount of compression involved. As I recall, full 1080p 60 fps video comes out at 3 Gbs uncompressed. As I understand it, this camera records at 28 Mbs, giving a compression of greater than 100:1. What can we expect with such a high compression rate ?

Mark,

For 1080p out, it uses the standard AVCHD compression at almost the highest bit rate for the standard @ 27 Mbps (AVCHD does up to 28 Mbps in spec 2.0). There are plenty of AVCHD camcorders out now that perform admirably with those figures at 1080p/60, examples are littered throughout this and other forums.

Also, it's been mentioned on some sites (like here) that this new camera by JVC will allow uncompressed video out, if so then you should have no problems with compression as long as it's applicable to 1080p uncompressed out. It would be highly unusual if they offered uncompressed 4K out but not uncompressed 1080p out, but stranger things have happened.

I think in the end compression shouldn't be that huge of a factor either way, all the preliminary looks at the live and pre-recorded footage that I've read about said that compression was a non issue (and this was on 4K monitors to boot).

Troy

[Mark Rosenzweig]

For 4K, as I understand it, the new JVC camera records each 108060p quadrant at 36Mbps, not 28Mbps. That is, by arithmetic, almost a 30% higher bitrate than the highest HD standard. Since there are four quadrants, the effective bitrate for the 4K picture is 4*36 =144Mbps.

[Justin Molush]

Originally Posted by Mark Rosenzweig

For 4K, as I understand it, the new JVC camera records each 108060p quadrant at 36Mbps, not 28Mbps. That is, by arithmetic, almost a 30% higher bitrate than the highest HD standard. Since there are four quadrants, the effective bitrate for the 4K picture is 4*36 =144Mbps.

This is what I was expecting, separate encodes for each of the four quadrants, resulting in a higher bitrate and little encoding artifacts. Now, what I am curious about, is what is it encoding 4k in? Is it an AVCHD variant in each of the four quadrants? (I thought AVCHD topped out at 28MBps...?)... Plus, if it encodes at such bitrate, why can't it do 4:2:2 at 1080p? That sort of sampling and bitrate seems trivial compared to providing a quad channel 4K output... correct me if I am wrong since I have been out of the engineering field for over 5 years now and a lot of things change quickly.

In addition, what are our options to create singular files? Its not like we can simply go into FCP and log and transfer 4K... Im sure the only way is the proprietary software the camera comes with to output into some 4:2:0 4K raster which isn't inherently bad because this seems like a compact, new age, UHD ENG camera. White balance and you should be good to go!

Im curious to see how this cam is applied professionally - I know I won't use it for my projects since 1080p is on the outer limits already of what is needed...

[Mark Rosenzweig]

Forget AVCHD. That is just a set of specs for HD standardization. The JVC encoding of each quadrant is in H264 at 36Mbps at 108060p with AAC audio compression . AVCHD *2.0* is 108060p H264 at 28Mbps maximum with audio encoding using AC3. There are also other attributes not specfied by AVCHD standards (CABAC or not, how many reference frames etc.).

[Troy Lamont]

Last time I checked, B&H had this in stock as of this past Sunday, has anyone heard or seen anything new yet?

[Glen Vandermolen]

Originally Posted by Troy Lamont

Last time I checked, B&H had this in stock as of this past Sunday, has anyone heard or seen anything new yet?

I just checked B&H, and it won't be available until April 5th. You can pre-order it, though.

[Troy Lamont]

One of the members over at AVSForum just received his, going through some preliminary testing and has posted a short 4K clip and a couple of full HD clips.

Enjoy

[Ronan Fournier]

So, what about some news about the interchangeable lens version shown during CES? Is there a protoype exposed at the NAB? Is there some new specs, price and release date?
Thanks!