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Author Topic: Blackmagic Video Assist 4K transcodes DSLR footage into true 10 bit 4:2:2ProRes?  (Read 2683 times)

Grischa Rueschendorf

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Does anybody use one of BM new video assist offerings? They claim that it records 10 bit recording in 4:2:2 ProRes and DNxHD footage on DSLRs via HDMI. I wonder how thats possible when for instance a Sony A7s/r 2 only records in 8 bit. My impression is that its just up-sampled.
Would that add any benefits to editing and grading?
any thoughts?

thx
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smthopr

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Does anybody use one of BM new video assist offerings? They claim that it records 10 bit recording in 4:2:2 ProRes and DNxHD footage on DSLRs via HDMI. I wonder how thats possible when for instance a Sony A7s/r 2 only records in 8 bit. My impression is that its just up-sampled.
Would that add any benefits to editing and grading?
any thoughts?

thx
I've recently been using a Sony A7rII. We started recording in camera, Slog, but now record to an atmos Assasin. I'm not sure that we get 10 bit out the HDMI port, but the quality of the recording is vastly improved. I think it's mostly better compression than the long GOP codec in the camera which shows a lot of compression artifacts using LOG. The in camera codec compresses motion with a lot of extra blurring as well.

I don't know about the BM device, but the in camera recording is pretty weak for any serious work.
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Bruce Alan Greene
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John Brawley

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Does anybody use one of BM new video assist offerings? They claim that it records 10 bit recording in 4:2:2 ProRes and DNxHD footage on DSLRs via HDMI. I wonder how thats possible when for instance a Sony A7s/r 2 only records in 8 bit. My impression is that its just up-sampled.
Would that add any benefits to editing and grading?
any thoughts?

thx

The recorder certainly does record UP TO 10 bit 422 containers of video.

You still need to feed it 10 bit 422 though if you want to fill that container.  Otherwise if you feed it 8 bit it will record those 8 bits into a 10 bit file.  You'll have a marginal advantage, but it's not turning 8bits into 10 bits.

You can also choose other flavours of quicktime to record to as well, and there are also 8 bit versions of ProRes.

You will find though that the compression of ProRes 10 Bit 422 is likely still better than the internal codec would be.

JB
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Grischa Rueschendorf

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thanks for all your responses.
BM customer service in Singapore also got back to me and basically confirmed that its Video Assist 4K will just wrap a 10 but container around it since none of the Sony DSLR will record above 8 bit. I guess its like pouring 8 litres into a 10 litre bucket.  But the records ProRes which is nicer to edit.

I played around with John Brawley's URSA footage in DaVinci 12.5 that he kindly made available. RAW does have a nice look to it and those files are quite malleable.
My own project is focused around quite contrasty retail interiors where extra lighting is not an option plus I would like to take advantage of shifting my Canon TSE lenses for perspective correction. I looked into the BMPC and BMPCC but the crop factor is too much and I am worried about low light performance. But I love the fact that the BMPC record ProRes and raw something even Sony's FS5 still can't do, let alone DSLRs

Hence me trying to get true 10 bit 4:2:2 footage out of Sony's A7R/S2s via an external recorder. I guess we can't have it all in one compact package. But who knows what Sony will pull out of their hat with the upcoming mk3s.

again, thanks a lot

Grischa
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Morgan_Moore

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I guess its like pouring 8 litres into a 10 litre bucket.

More like 2.5 litres into a 10 litre bucket.
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eronald

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the fs5 will ge able to record raw to an external revorder, next firmware update.

thanks for all your responses.
BM customer service in Singapore also got back to me and basically confirmed that its Video Assist 4K will just wrap a 10 but container around it since none of the Sony DSLR will record above 8 bit. I guess its like pouring 8 litres into a 10 litre bucket.  But the records ProRes which is nicer to edit.

I played around with John Brawley's URSA footage in DaVinci 12.5 that he kindly made available. RAW does have a nice look to it and those files are quite malleable.
My own project is focused around quite contrasty retail interiors where extra lighting is not an option plus I would like to take advantage of shifting my Canon TSE lenses for perspective correction. I looked into the BMPC and BMPCC but the crop factor is too much and I am worried about low light performance. But I love the fact that the BMPC record ProRes and raw something even Sony's FS5 still can't do, let alone DSLRs

Hence me trying to get true 10 bit 4:2:2 footage out of Sony's A7R/S2s via an external recorder. I guess we can't have it all in one compact package. But who knows what Sony will pull out of their hat with the upcoming mk3s.

again, thanks a lot

Grischa
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Morgan_Moore

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12 bit linear raw has a bad name for noise if your DR is beyond about 6 stops. Not enough levels in the shadows.. poor raw in the FS7 at the moment.

Raw needs log encoding and or 14 bits linear. 14bit wont AFAIK go down a single SDi

So Id await FS5 raw in the wild before banking on that.

S
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John Brawley

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the fs5 will ge able to record raw to an external revorder, next firmware update.

Like Morgan, I too have heard some very unflattering things about the Sony FS RAW.

I've used F55 4K and 2K RAW which are both 16bit lin and it's great.

JB
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Grischa Rueschendorf

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Once the RAW update is available how does one get raw imagery out of this puppy ? Would the BM video assist 4 K do the trick or is the Odyssey 7 needed which is considerably more expensive.
If the FS5 could output decent raw that would make up for the lack 10 bit internal UHD
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John Brawley

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The Blackmagic will only record a regular SDI feed, so even if it's in LOG it's not RAW data.  Some external recorders like the 7Q and 7Q+ will allow you to record a RAW stream, but generally only on cameras the option specifically to output RAW over SDI and only if you also enable (at extra additional cost) RAW recording licenses in the 7Q / 7Q+

You also want to REALLY check what they support and don't support.  I've bought two of their recorders on the promises of certain features and it was nearly 2 years before they were enabled :-)

Read more here.
https://convergent-design.com/products/odyssey-raw.html

JB
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