HDMI Out

[Felix van Oost]

I know the NX5 outputs uncompressed 10-bit 4:2:2 via HD-SDI, but does it output the same to the HDMI output? The reason is that I would like to record uncompressed in-the-field with a laptop (nanoFlash is way too expensive), but the only HD-SDI cards I can find are PCIx, which means I would have to get a separate housing for it to work with my laptop. I've been looking at the Blackmagic Intensity Shuttle which works over USB3.0 and is portable, but it only has an HDMI input. So can anyone tell me if the HDMI stream is the same as the HD-SDI?

[Arkady Bolotin]

Felix:

Here is the quotation from “Notes on Video” blog, posted by Michael Murie on Wednesday, January 20, 2010:

“I spoke to Juan Martinez, Senior Product Manager, Sony Broadcast & Professional AV Products, and he clarified a few more details of the HXR-NX5 for me.

Is the HDMI signal 10 bit 4:2:2? 1920 x 1080?
Yes. The camera captures at 1920 x 1080 4:4:4, then converts to 4:2:2 before encoding.”


Also, according to another source, Media-Solutions.US, “uncompressed digital HD video and audio signals are output from the HDMI connector. During shooting, a pre-compressed 1920x1080i/4:2:2 signal is output from the HDMI connector”.

[Victor Wilcox]

In the VASST DVD "Inside the Sony HXR-NX5U Camcorder" Douglas Spotted Eagle states that in the 10-bit HD-SDI output, the top two bits are zero, yielding 8-bit data.

[Felix van Oost]

Thanks for the clarification. So, the HDMI connector only outputs 8-bit, but is this compressed or uncompressed? The sources seem to contradict each other on that.

And on the flip side, is the HD-SDI output then full 10-bit uncompressed? Or does it have the same 8-bit limitation and compression as HDMI out?

[Arkady Bolotin]

Excuse me, Felix, but where did you see a contradiction?

Both trusted sources certainly confirm that uncompressed HD video and audio signal 10-bit 4:2:2 1920x1080 is output from HDMI connector during shooting.

[Ron Evans]

I think Felix is saying that if the 10 bit output has only has 8 active bits its really an 8 bit output in a 10 bit stream. I think its something that needs clarifying from Sony.

It may be a 10 bit output but if only 8 bits have any value its a bit like selling 800ml of milk in a 1000ml container and calling it 1000ml of milk !!!! I know that the difference between 8 and 10 bit streams is even worse than this example.

Ron Evans

[Arkady Bolotin]

That’s absolutely correct, Ron. The difference between 10-bit and 8-bit signals is as huge as the difference between 2^10 = 1024 (2 to the power 10) and 2^8 = 256 (2 to the power 8).

This means that 8-bit signal contains information of (2^8)^3 = 16,777,216 discrete colors, whilst 10-bit signal has (2^10)^3 = 1,073,741,824 colors. Thus, raising the color bit-depths by just 2 bits increases the total quantity of recorded discrete colors by a factor of 64 times.

[Felix van Oost]

Thanks Ron, that was what I was trying to say. I've always heard Juan Martinez say the output is 10-bit, so it seems strange that the output would only actually be 8-bit.