gh5: new v90 card good enough for 4k60 hdr? 400mbps?

Started 1 month ago | Discussions thread
Sean Nelson
Sean Nelson Forum Pro • Posts: 12,524
Re: gh5: new v90 card good enough for 4k60 hdr? 400mbps?

LingoDingo wrote:

Yes, in hindsight I was mixing up data-size with value range.

Bravo, for what little it's worth you have earned my respect.

...But I still wonder what the effect of going from 8-bit recording to 10-bit recording has on the actual processing requirements of the camera. It's definitely going to effect image encoding in a big way, especially if the GH5 is performing color sub-sampling for 9 adjacent pixels for every pixel in the recorded image. ( Panasonic's internal PowerPoint from January 2017 listed this as a new GH5 feature )

I think you're probably right - the wider data paths between the sensor and encoder are unlikely to be a major difference, but the encoder is going to have more work to do to.

If it was simply a data processing issue, then overclocking an 8-bit camera processor by 30 percent should enable 10-bit recording, and make 10-bit recording a very common thing.

Even if you could "overclock" a camera, the additional heat would be an issue and it would also have a big impact on battery life.  Among the various "consumer" 4K camera manufacturers, Panasonic strikes me as having the best understanding of how to deal with kind of heat issues that have to be overcome while trying to wrangle that much data - and they reportedly had to struggle to minimize the size of the GH5 so that it would record reliably under the worst conditions without overheating.

I think it's a multifaceted challenge that includes the right kind of sensor readout, getting enough processing power at the right price point (especially bearing in mind that these camera chipsets have a limited production run and so their per-unit cost is much higher than you'd find in a mass-market device like a phone), heat management, and improving the support for kind of high SD card data rates you need so that you have some place to dump such a large volume of data.

At the end of this month the GH5 will have been in stores for 6 months now, but so far no competitors have come forward. And now I wonder if there will be any 4K 10-bit competitors announced by the time NAB 2018 rolls around next year ?

Sony seems to be the only other manufacturer who has very much interest in selling gear with "prosumer" video specs - so that's where I'd look first for competition.  Of course there's a lot of even more capable video gear, but not at such moderate price points and not in the kind of hybrid camera format that lets me kill two birds with one stone.

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