IO Express HDMI out not working properly

[Jorge Torrens]

[Jeremy Garchow]That’s a rather broad assumption. The purpose of the calibration is to calibrate the material to your output. Also, DVI is 8 bit, and HDMI 1.3 is 10bit. The HDP2 and ioExpress can both output true 10bit HDMI 1.3a signals

Yes, but shouldn’t the levels of all the outputs been the same, leaving aside the difference between 8bits and 10bits, or in other words if I were to monitor the diferent outputs in a waveform monitor I should not see any difference, shouldn’t I?, If it were the case then I should not have to recalibrate my monitor when changing the outputs in the card.

The blackmagic outputs 8bits, but it also works with both HDMI and DVI, is equivalent to the HDP2 with the very important difference of not supporting HDMI 1.3, the reason why I changed to Aja after years of using blackmagic products.

[Jeremy Garchow]
[Jorge Torrens] “but then how it is posible that the Dreamcolor sees the image as RGB, otherwise it would not allow to select a colorspace?”

The ioExpress is outputting RGB.

I was refering to what Gary said about the IoExpress not being able to output RGB at the moment from animation packages as Nuke, or at least this is what I understood.

Thanks again

Jorge

[Gary Adcock]

“[Jorge Torrens] “but then how it is posible that the Dreamcolor sees the image as RGB, otherwise it would not allow to select a colorspace?”

[Jeremy Garchow] The ioExpress is outputting RGB. “

This is one of those tricky areas in communication.

Technically the HDMI output is RGB – Since the Io Express v1.0 was not designed to handle the RGB Video Out signal from animation or graphics applications.

The default setting for ALL HDMI devices is to output RGB.

All RGB is not created equally. Also remember that HDMI is not and has not been considered anything more than a Consumer grade connection.

It was designed initially as a low cost AV connector for computer monitors and displays- that has been accepted as the default for Home Video and Television connectivity , it does not carry any ancillary data other than the HDCP digital rights protection.

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

[Jeremy Garchow]

[Jorge Torrens] “Yes, but shouldn’t the levels of all the outputs been the same, leaving aside the difference between 8bits and 10bits, or in other words if I were to monitor the diferent outputs in a waveform monitor I should not see any difference, shouldn’t I?”

Yes, this is the point of calibration. Nothing is the same. NTSC, Never The Same Color. Different devices handle the signal path differently.

[Jorge Torrens]

Ok, so what you mean is that although the IoExpress does not see a RGB image from Nuke the Dreamcolor assumes that because the signal is coming from HDMI it should be RGB?

Jorge

[Jorge Torrens]

News from Aja, I have just received a mail from Rudy in Aja technical support telling me that engineering in Aja has replicated my problem and there will be a driver fix in the next couple of weeks.

So I will use the adjusted black level in the mean time and see what happens with the new drivers.

Thank you very much Gary and Jeremy for the time that you have spent looking into it, and for me it has been a very informative conversation, and also thank you Aja for a very good and prompt technical support.