I sent an email off to Sony Broadcast UK last week asking about the discrepancy between the FS100 specs in the US and the UK.
In the US you can get 8bit 4:4:4 out of the HDMI socket while in the UK it was claimed to be 4:2:2, I decided this was nonsense and today came back the amazing reply…
Regarding this question, we would like to answer as follows.
Simple version:
Q. What is the signal of HDMI output?
A. It is “YC422 8bit” which is one of the HDMI output standard (EE/PB).
(Both FS100 and NX70)
Detailed version:
Q. What is the signal of HDMI output?
A. It is both “RGB444 8bit” and “YC422 8bit” which are one of the
HDMI output standard (EE/PB).
* Both are automatically changed according to connecting equipment.
Basically, “YC422 8bit” is output. If connecting equipment can receive
only RGB, “RGB444 8bit” is output.
(Both FS100 and NX70)
HDMI is very flexible for the resolution and bit, it can have 4:2:0, 4:2:2 and 4:4:4.
On the other hand, the data of the image created by the FS100/NX70 processor is just 4:2:2.
Then it is lifted up to 4:4:4 in the HDMI processor if the connected device is 444 capable.
(In fact, nobody knows the 444 HDMI device.)
But the picture quality is 422 (422 is just in 444 bucket).
As I read it and I am still a bit confused…You can get 4:2:0, 4:2:2 or 4:4:4 out of the HDMI socket but this depends whats plugged into the FS100 or the NX70.
Thanks for getting this information from Sony.
So my reading of this is that the 4:4:4 RGB output is basically irrelevant; both because it’s being derived from the 4:2:2 YC422 signal anyway, as well as because practically no recorders support 4:4:4 RGB (the only one I know of is Sony’s own, very expensive, SR-R1 recorder)
Isn’t RGB 4:4:4 just a slightly odd way of saying a normal RGB signal – i.e. the red green and blue is carried full bandwidth with no chroma subsampling like the classic VGA monitor connection?
In which case as I read it they are saying that the video subsystem is inherently 4:2:2 but that if you connect an RGB device the HDMI processor will do the chroma decoding to put out an RGB signal.
So you are not gaining anything as the quality will still be inherently 4:2:2, just flexibility.
After a bit more digging it looks like all HDMI connectors are *required* to support RGB 4:4:4 as the baseline connection if the two devices do not share any other modes, the YCrCb formats are actually optional. That makes sense as it means any device that can’t do the chroma decoding is still going to work as the device that can will convert it before it sends it over HDMI.
If this is true I hope folks realise it before they drop large money on external recorders.
This is great news but does the NX70 output a clean HDMI signal?
I suspect it’s irrelevant from the point of view of wanting to add an external high grade recorder, but if you want to plug in an external RGB monitor it’s probably a good thing.
I think someone in marketing that knew about the Sony recorder enough to grasp that RGB444 can be an indication of high grade video saw this on an engineering spec and jumped to conclusions.
So if I understand correctly, the NX70 can do live capture output over the HDMI without having to record to the internal hard drive? Is this tested with the Black Magic Intensity Extreme? I have a new Macbook with Thunderbolt and a Pegasus R6 with about 7TB of storage left on it. Would that be enough to capture 2 hours of footage through the HDMI?