Blackmagic Mini Converter + BMPC 4k output problem

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Calvin Hartwell

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Blackmagic Mini Converter + BMPC 4k output problem

PostTue Sep 10, 2019 6:56 pm

Hi all!

I have been testing different ways to capture 4k video from my Black Magic Production 4k Camera live through the SDI output port for live video.

I managed to get 1080p live video via an EPIPHAN AVI SDI->USB3 and it works pretty well, but goes blank when pushing out 4k. I believe this is a limitation of the Epiphan device and not the camera.

However, I am currently testing with a BlackMagic Mini Converter for SDI to HDMI 4k and I am still getting the blank output on a 4k monitor. 1080p works fine.

Does anyone have any ideas?

Cheers,

- Calvin
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carlomacchiavello

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Re: Blackmagic Mini Converter + BMPC 4k output problem

PostTue Sep 10, 2019 10:25 pm

Are sure that your sdi cable support 4K?
I remember that with my old Bmpc4k the common sdi work fine for 1980p, but blank with uhd, when I changed with better sdi cable 4K certied problem disappear. The same is with ursa mini pro


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Denny Smith

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Re: Blackmagic Mini Converter + BMPC 4k output problem

PostWed Sep 11, 2019 1:20 am

The Production Camera 4K only has a 6G SDI, if I remember correctly, the camera only outputs 1920x1080P (1080i60 added), the max it would output would be UHD 2160p, as the Camera only records UHD 3840x2160 ProRes and 4000x2160 in Raw only, so it is not going to output a full 4K signal. ;)
Denny Smith
SHA Productions
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Calvin Hartwell

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Re: Blackmagic Mini Converter + BMPC 4k output problem

PostWed Sep 11, 2019 8:58 am

Thanks for the replies all, I will try a newer 12G SDI cable and see if it makes a difference.

Denny Smith wrote:The Production Camera 4K only has a 6G SDI, if I remember correctly, the camera only outputs 1920x1080P (1080i60 added), the max it would output would be UHD 2160p, as the Camera only records UHD 3840x2160 ProRes and 4000x2160 in Raw only, so it is not going to output a full 4K signal. ;)


Just to clarify, I am using the bigger "Blackmagic Design Production Camera" and not the pocket and I have the 4k version with the Canon EF mount. Reading the small print:

The Blackmagic Production Camera 4K uses standard connections, so you never need to source custom cables. It includes a 6G-SDI connection for Ultra HD resolution or down converted HD output over a single SDI cable. The built in Thunderbolt connection lets you plug into a laptop computer and use the included UltraScope software for real time waveform monitoring, and the 1/4" jack mic/line inputs enable high quality uncompressed audio recordings. Other connections include a 12 to 30 volt DC input, a 3.5mm headphone input socket and LANC remote control.


Seems that it does have a 6G SDI interface which can serve Ultra HD (3840x2160 ProRes, not sure about RAW) so this should do what I'm after. However when I put it into this mode, the screen goes blank. Maybe this will be solved by a new cable.

What do you mean by "full 4k signal"? My understanding was that UHD is 4k (3840x2160), but there is also "Cinema 4K" (4096 x ????). Which mode or resolution are you referring to?

Thanks for the help! :D :D
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Denny Smith

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Re: Blackmagic Mini Converter + BMPC 4k output problem

PostWed Sep 11, 2019 5:33 pm

OK, good you find the output resolution specifications, I was not sure. As for video resolutions, UHD is 3840x2160, full 4K DCS is 4096 x 2160 (4K DCI), you do not need 12G SDI cable, a 4/6G cable is fine.

The Production Camera 4K, nor any BMD Camera, does Not output Raw Video, SDI out is only a YUV, 4.2.2. Video signal at the frame rate set in the camera, in this case you get UHD, to 30fps. However, if yiu select a clean feed out the SDI, then the camera may on,y output a 1080i signal, this is how BMD implemented 1080i on the earlier cameras. The camera was not really designed to record UHD out the SDI, which was intended for monitoring purposes, as recording was done in camera.

Try hooking the camera up directly to a SDI camera monitor that can accept a UHD resolution signal, and see what the camera is actually outputting at the settings you have set. Often many older adapters do not support UHD, or they do not support SDI A settings used by BMD.
Cheers
Denny Smith
SHA Productions

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