View Full Version : How can I check the specs of a video signal of an HDMI cable?


Christos Oscar Kambiselis
June 16th, 2013, 03:23 PM
I'm trying to find information on how to check the specs of an HDMI video signal, chroma subsampling (4:4:4, 4:2:2 etc), bit depth (10-bit, 8-bit etc), color space (RGB, YCbCr, Rec. 709 etc) and others, without having to buy a 5000€ waveform monitor, is there any software that can get the signal from a video card and give me this information, I don't need to know the signal quality but it's specifications, as I cannot get this information from the products manufacturer?

Chris Medico
June 16th, 2013, 03:39 PM
That isn't as hard as you think. HDMI is a consumer standard and is negotiating. To be HDMI 1.x compliant it must be capable of YUV or RGB at multiple bit depths.

Is there a specific reason you are looking to know the output signal? It may change depending what display the source is plugged into.

Christos Oscar Kambiselis
June 16th, 2013, 03:45 PM
I have a Nikon D600, and after many messages with different Nikon support centers I still don't know the exact specs of the HDMI output, the main reason I need to know the specs is to buy the correct recorder, like should I get the Blackmagic HyperDeck Shuttle, that can record 4:2:2 10-bit or should I get something better that could record in higher quality, 4:4:4 etc.

Chris Medico
June 16th, 2013, 04:05 PM
My PIX240 will do that. If you know someone near you that has one you can connect a PIX240 or PIX220 to your camera and see the video mode.

Christos Oscar Kambiselis
June 17th, 2013, 09:32 AM
Thanks, good to know that, any other suggestions are welcome!

Brian Drysdale
June 17th, 2013, 09:38 AM
I don't know if Mediainfo would be of use: MediaInfo (http://mediainfo.sourceforge.net/en)

Christos Oscar Kambiselis
June 17th, 2013, 02:04 PM
Hi Brian, I'm not looking for the file specifications but the HDMI signal coming out of a device.

Giroud Francois
June 18th, 2013, 03:39 PM
as said above, HDMI output is able to output almost anything, but will negotiate with the device (usually a screen) for a compatible format.
HDMI 1.3 is able to use 30, 36 and 48 bit so it goes well beyond the usual 24 (3x8) bit we used to see.
But probably you will see such range (10, 12 or 16 bit) only on high end computer card and find no display to use it.
Most HDMI signals are 8 bit, simply because they almost use all the same chip, that is limited to 8 bit , as most displays are because HD use REC709 color space defined on 8 bits.
So it would be very uncommon you get 10 bit hdmi output on a consumer level device.
but what you could get is the extended gamut also called xvYCC.
i think the blackmagic hyperdeck is recording in that mode if present (sony cameras for example)
That is due to the fact that REC709 color space designed for HD (SD use the REC601) is limited to 8bits, but also do not use the full range (0 to 255) but only 16–240.

You can more easily find 10 bit HD, but on HD-SDI signal, and most of time, it is only 6 bits padded with 2 additional useless bits.

there is another standard called Deep Color, offering
As for the 4:2:0 vs 4:2:2 vs 4:4:4, you can expect that most signal are 4:2:0 (standard in AVCHD).

Christos Oscar Kambiselis
June 29th, 2013, 12:09 PM
Yes AVCHD is 4:2:0 but the camera is supposed to output uncompressed signal of the LiveView, I could expect it to be at least 4:2:2. All the specs I wrote were just examples to clarify what I was talking about since sometimes the terminology is a lil bit different or not known, we can clearly speculate many things but I still need the actual signal info. The info I need to check would be something like in the top left window of this pic. http://ru.tek.com/sites/tek.com/files/media/image/WFM2200MultiformatMultistandardPortableWaveformMonitor-4-L.jpg

Christos Oscar Kambiselis
June 29th, 2013, 12:48 PM
Giroud even though your comment in the chip used was incorrect it made me look into the Nikon Expeed 3 image processor used by the D600 and found out that it outputs 4:2:2 8-bit signal and probably higher if the guys at NIkon Hacker get around the code.