Recording RGB over HDMI

[Gary Adcock]

[Tom Bridges] “Is it possible to record RGB signals over HDMI with the KiPro, or is it just YUV that’s supported? “

From the KiPro Manual.
A Note About RGB—Although RGB is used less in today’s video systems, Ki Pro
supports it at both input and output. Because Ki Pro’s (and SMPTE SDI) native
format is YPbPr, AJA recommends the use of YPbPr whenever possible. Although
component video monitors often have RGB inputs, it’s better to use YPbPr when
the monitor supports it. The YPbPr format provides “headroom” for “superwhite”
and “superblack”—and these video levels will be clipped when transcoding to RGB.
Also, the RGB/YPbPr transcoding involves a level translation that results in
mathematical round-off error.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php

[Tom Bridges]

Hi Gary,

Thanks for replying: very much appreciated. Are you sure that doesn’t apply to RGB over SDI? I have a dim memory of reading somewhere that the KiPro doesn’t in fact support RGB over HDMI, but I can’t remember where it was – and I’m trying to confirm either way!

Many thanks for your help,

Tom

[Tom Bridges]

Hi,

Just in case anyone’s following this thread, and wants a definitive answer: I spoke to AJA, who have confirmed that the KiPro doesn’t record RGB over HDMI – for the time being at least. Which is a shame: it would have been a nice solution for what I have in mind.

Thanks,

Tom

[Gary Adcock]

[Tom Bridges] “Are you sure that doesn’t apply to RGB over SDI?”

yup.

The truncation commented on in the manual quote is more pronounced in HDSDI where the RGB is limited to 8 bit in a single HDSDI feed, since HDMI was designed with output displays in mind it usually defaults or converts to RGB < see HP Dreamcolor display>

I tested with
Arri D21 > 4:4:4 RGB Dual Link HDSDI > Hi53G as RGB HDMI > to RGB 4:2:2 10bit on the KiPro.

The real question is what are you trying to capture as RGB? and why does it need to be over HDSDI
Video in Y’Cr’Cb not RGB.
Animation is RGB.

My guess is you are doing something that is going to run into HDCP issues.

gary adcock
Studio37
HD & Film Consultation
Post and Production Workflows for the Digitally Inclined
Chicago, IL

https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php

[Fred Jodry]

Tom, Y, c~R, c~B is a rematrixing of R, G, B (and synchronization). Although it`s a pain to get a matrixing box to convert either one to the other, they`re made. The only advantage to using Y, c~R, c~B is that it has a clamped luminance signal Y ready to use for B/W uses. The common Synch- On- Green variation can cause green- purple black level drifting nightmares. Start a pencil notebook on equipment availability, technical terms, cable types, troubleshooting, and so on. Audio combining, synchronization, and extraction notes will hit the same notebook. Don`t insert AACS codecs and protection schemes during production or editing, one reason is that it will make your work more archivable; they can be put in at sendoff.

[Maurice Jansen]

best question is

where dou you want it to use for exactly????

and what is the rest of the setup.

greet
Maurice

People saying they don’t make mistake’s often make nothing at all!