Video Devices PIX-E7 7-inch 4k Recording Monitor Now Shipping!

P

Paul Isaacs

Active member
That seems like a nice device at a decent price. I like the XLR add-on. Also not horribly overpriced. Can USB3 handle 4K 4444 ProRes XQ at 30fps though?
 
Their caddy provides a USB3 interface for offloading footage, but internally they use some SATA variation to write to the card when recording, based on the conversation I had with them at NAB in April.
 
Where in the spec does it say 4K ProRes 4444XQ? Exactly what source currently available would send that to the recorder?

I believe the ProRes 4444XQ is for HD recording.
 
This is what they say in the user's manual:
To record using the ProRes 4444 XQ codec, the PIX-E7 must detect a LOG-encoded signal, such as Sony S-log2, over SDI. This is an Apple® requirement. If the connected video signal is not 4:4:4, the PIX-E7 will prevent selection of ProRes 4444 XQ and ProRes 444 codecs. If those codecs are already chosen and a 4:2:2 video signal is connected, the PIX-E7 automatically adjusts codec selection to ProRes 422 HQ.
Click to expand...

The PIX has 6G-SDI. That should be enough to transport 4K raw at 60fps, which I guess you could then encode as ProRes 4444, but that seems overkill since a raw signal would have nowhere near 4:4:4 color sampling. But it seems like it could do it if that's what you wanted.

There's a chart that shows data rates and the appropriate SDI level to transport them, in this article.

From what it says, a true 10-bit 3840 x 2160 4:4:4 source would require 12G-SDI to transport, and even then, only at 30P. Even 12G-SDI is insufficient to handle 3840 x 2160 4:4:4 at 60p, even at 10-bit, much less 12-bit.

6G-SDI should be plenty enough for 1080p or 2K 4:4:4 recording.

So from what I'm seeing, it seems to be saying that you can use ProRes 4444 for HD or 2K recording, and possibly for encoding the 4k raw log signal.
 
Barry_Green said:
The PIX has 6G-SDI. That should be enough to transport 4K raw at 60fps, which I guess you could then encode as ProRes 4444, but that seems overkill since a raw signal would have nowhere near 4:4:4 color sampling. But it seems like it could do it if that's what you wanted.
Click to expand...

How is 6g-sdi enough for 4k raw 60fps? Even at only 12bit (which is a very thin bit depth for linear raw) 4k 60fps bit rate is over 6.3Gbps which is well over 6G(bps) sdi. Even that is too high and already requires a way of fitting a 14 or 16bit signal into 12bit, and actually doing 60fps means implementing some kind of proprietary compressed raw data stream.

Sony for example is able to send 12b 60fps 4k raw over 3g-sdi by using proprietary 3.7x compression and also applying whitebalance and slog transforms prior to sdi transport. I'm not familiar with any other instance where any manufacturer has achieved this, though.
 
Last edited:
The Canon C500 sends 4K60p over dual-3G SDI links, which is equivalent to one 6G-SDI link.. Canon's RAW is limited to 10-bit which is why they bake in several settings in the signal.

The PIX-E7 doesn't accept any RAW signals, at least not at this time, so I'm not sure how we transitioned there. Reading the specs on the website, it is clear that the ProRes 4444 and 4444XQ modes are for HD video signals, not 4K. The same limitation is on the Odyssey7Q+. And as noted, there currently is not any camera system outputting a 4K 444 signal anyway.
 
Mitch Gross said:
Reading the specs on the website, it is clear that the ProRes 4444 and 4444XQ modes are for HD video signals, not 4K.
Click to expand...

My mistake. Although in my defense I don't think it's clear on the website what the limitations of its 4K recording are. Possible sources aside. Even from the opening image there is this:

pix-e.jpg

Which can be assumed to mean the two are compatible.

Nowhere on the specs page does it list which codecs are compatible with which resolutions/framerates. So maybe you know this from prior knowledge and thus it's more clear to you?
 
Interesting. I believe that the website has changed from before this unit delivered. I do not wish to speak for Video Devices as I'm sure they would not try to speak for Convergent Design. I'm sure Paul can clarify this if you ask him.

I will state that at this time I know of no camera that outputs 4K in a 4:4:4 signal, and certainly not one that would do so with an Alpha channel (the 4th "4" in 4444) or in 12-bit. It is certainly possible to generate such a video signal in a computer using a graphics program, or to use a 6K or preferably an 8K RAW signal or 6/8K 4:2:2 signal in 10-bit to begin to interpolate out of this a 4K 4:4:4 12-bit. But that work would happen in a computer so I don't know why one might then go to an onboard recorder via a SMPTE video signal instead of data. Also recorgnize that 4K 4444(XQ) 12-bit is a monstrous amount of data. I'd have to do some math but I'm not sure that the media could handle the data rate.

For the record, the Odyssey7Q and Odyssey7Q+ can record Apple ProRes 4444 and 4444(XQ) in 12-bit in HD and 2K up to 60p.
 
You must log in or register to reply here.
Back
Top