What data rate is the blackmagic production camera 4k?

Sorry I cant find the info in the manual or online anywhere for some reason.

Is the 4k Raw now compressed with the latest firmware?

Are there option in camera to select various Raw flavours?

Is the only raw pixel size 4k?

What is the data rate for 24p 4k raw compressed?

Thanks

Hey Jon,

The 4K Raw has been the compressed raw since its release I believe. It's the lossless compression so it's only mathematically compressed. That's the only raw option though, so you won't be able to select 4:1 or 3:1.

I need to check this again, but these were my notes about a year ago.

Raw 4k
8.7 MB per frame
12.7 GB/m, 763 GB/hr
480 GB = 37 minutes

4K ProRes HQ
5.3 GB/m, 319.8 GB/hr
480 GB = 90 minutes

Nice one thanks

You can click on the tab for the BMPC4K cameras here:
https://www.blackmagicdesign.com/produc ... /techspecs

I do my own calculations since I've found the published figures to be off what I'd expect. Raw losslessly compressed will vary with the complexity of the scene. It may also be different than what are seen on other cameras if the routines used are different than the other cameras. I use a lossless compression factor of 1.3x. When lossless compression was first introduced, BMD was sometimes using a factor of 1.5x but that hasn't been supported by some actual experiences, so I use 1.3x. Could be even better for simple scenes or worse for very busy motion scenes. The published raw data rate of 265 MB/s for raw is a lower value than what I'd expect.

Lossless compressed raw:
4000 x 2160 = 8,640,000 photosites
X 12 bits per photosite = 103,680,000 bits
/ 8 bits per byte = 12,960,000 bytes per frame
/ 1.3x lossless compression = 9,969,230 bytes per frame
X 30fps = 299,076,900 bytes per second or
about 299,400,000 bytes per second including audio. That would result in about 27 minutes recorded on a 480GB SSD. Always a good idea not to push the SSD to capacity, so think in terms of less than a half hour recording at 30 fps or about 33 minutes at 24 fps.

ProRes 422 HQ UHD uses a target of 110MB/s at 30 fps or about 72 minutes recording on a 480GB SSD. At 24 fps, you can record 90 minutes as David mentioned.


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The previous post gives the rationale but here's the short story:

The ProRes recording for 90 minutes on a 480GB SSD is correct for 24 fps. About 72 minutes if 30 fps.

The data rate for raw David mentioned is lower than what I'd expect. I assume a compression factor of 1.3x and that gives about 33 minutes for 24 fps and 27 minutes for 30 fps.


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Ah great, thanks Rick.

Can anyone advise if the BMPC4K camera ProRess HQ 3996x2160 is 4K? I'm a bit confused about this...

Lisa see the responses to your other post on this same question.


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