HD-SDI 8-bit to 10-bit Ki Pro

[Keith Pratt]

Just to expound upon what Jeremy’s said:

I think I’m right in saying HD-SDI is necessarily 10-bit. The only question is whether it is a genuine 1024 gradations or a “padded” 256 (8-bit).

The three pivotal points in image capture are:
Camera sensor’s A/D
Camera’s processing
Recording

The Sony F900R has a 12-bit sensor A/D, 10-bit processing and onboard 8-bit HDCam recording. Record the live HD-SDI feed and you’ll get genuine 10-bit.

Not sure of the Canon XL-H1’s A/D, but its 8-bit processing, which is (necessarily) done before HD-SDI output, means you are getting 8 bits padded into a 10-bit signal. So in this case, yes, the damage has been done.

Something can be gained by interpolating the 8 bits into 10 — and some hardware, as well as the likes of Cineform’s software, might do this too — but it’s not going to be as good as recording genuine 10-bit in the first place.

[Rafael Amador]

[Craig Meadows] “Just curious technically what happens when you feed the 8-bit signal out of a camera capturing to 10-bit ProR”
You just add to “0” to the end of each Y’, C’b and C’r value.
You increase the data rate in a 20% and don’t get nothing in exchange.
Is an 8b picture enveloped in an 10b pack.
Rafael

http://www.nagavideo.com