720p/1080p/2k Confusion

[PaulClements]

I decided to post a new thread as this question would be bound to get lost in the ever increasing post by Jim. Frankly I don't understand the debate, so please if someone can explain it to me I'd be grateful.

The point I find confusing is this:

If the camera is modified to output at the maximum 2k and can therefore manage 96fps it cannot do 720p or 1080p because the FPGA cannot afford both - Correct?

How then does the camera produce a 720p and 1080p out for monitoring? Surely the camera is already processing the information into these formats regardless of what it is outputting to flash or the RedDrive?

According to current spec the output from the HD-SDI is 1080p 444 or 720p 422 so it isn't as if this output is poor quality.

Why couldn't the same output be relayed to the red-drive or flash and recorded, allowing for the 2k @ 96fps to exist also.

[Michael Mann]

I would like to know this, too.

[Anders Holck]

I dont know, but the deal might be the extra Redcode RGB codec.
The HD SDI output is uncompressed which cannot be recorded, So this data would have to be compressed with a 1080p Redcode RGB codec.

[PaulClements]

But this output can't be larger than what feeds to the CF or Reddrive because otherwise why would we need an additional RAW port since we'd have an HD-SDI port capable of delivering high bandwidth. This output must be compressed and why would Red include a second compression other than the original RGB that they included from the getgo?

[Anders Holck]

No, the HD-SDI is after debayer/processing but before any compression.
The RAW port is like it says 12 bit RAW. The HD SDI is baked 1080p in 10 bit REC709.

The 4:4:4 RGB 1080p 30p bus is something like 190 MB/s

[Paul Plonka]

So is it possible to record through HD-SDI on HDCAM deck ?
paul

[Anders Holck]

Yes, that is possible. The HD-SDI master outputs should be live in any recording format, and offers either 4:2:2 or 4:4:4 DL.
You loose the RAW advantage though

[baro]

So is it possible to record through HD-SDI on HDCAM deck ?

Now this is a good question.

[I Bloom]

I decided to post a new thread as this question would be bound to get lost in the ever increasing post by Jim. Frankly I don't understand the debate, so please if someone can explain it to me I'd be grateful.

The point I find confusing is this:

If the camera is modified to output at the maximum 2k and can therefore manage 96fps it cannot do 720p or 1080p because the FPGA cannot afford both - Correct?

How then does the camera produce a 720p and 1080p out for monitoring? Surely the camera is already processing the information into these formats regardless of what it is outputting to flash or the RedDrive?

According to current spec the output from the HD-SDI is 1080p 444 or 720p 422 so it isn't as if this output is poor quality.

Why couldn't the same output be relayed to the red-drive or flash and recorded, allowing for the 2k @ 96fps to exist also.

My understanding is that the FPGA is responsible mostly for the wavelet compression and also probably the debayering and scaling. Each design that is placed on the chip is likely heavily optimized to do exactly one task very efficiently. So, for example, it downconverts 4K Bayer pattern to 1080p and compresses it, but the parameters are not that flexible within each mode.

The HD SDI is much simpler. It's not compressed at all. So recording off of this with a deck is not really a terrible idea, as Anders points out, you just loose the wavelet compression and the 12bit RAW. I'm looking into ways to do just this, in the case that a client doesn't want to switch to a new format, and I still really want their bussiness.

IBloom

[Rocco Schult]

How then does the camera produce a 720p and 1080p out for monitoring? Surely the camera is already processing the information into these formats regardless of what it is outputting to flash or the RedDrive?

According to current spec the output from the HD-SDI is 1080p 444 or 720p 422 so it isn't as if this output is poor quality.

From what I remember from NAB, because I was asking rather specific:
The HD out(s) are hardware scaled with whatever chip/DSP doing exactly that job. And its doing a 2:1 scale, because thats more easy to accomplish at a good quality. Odd scales need more complex DSPs (bicubic interpolation). Hence the output in 1080 is a cropped output from half of 4.5k.
Dont ask me about the 720.