development towards 1080p50/60

[Cees van Kempen]

Dear Dan / CF team,
With the panasonic AF100/101 on the market, 1080p50/60 is now available for many of us, however not with the nano. Is there any devolpments foreseen for an upgrade making this possible with a nano?

Cees

[Dan Keaton]

Dear Cees,

In the specific case of the AF100, which uses single-link HD-SDI at 1.485 Gbps, there is not enough bandwidth to output 1080p50, 1080p59.94 or 1080p29.97.

Thus, the nanoFlash never sees these framerates nor does that AF100 output them over HD-SDI.

[Cees van Kempen]

Dear Dan,

Thanks for your reply. I did not make my question clear, I also don't own the specific camera I mentioned. It is the general development of camera's moving towards 1080p50/60 that made me wonder if CD is moving the same way.

Cees

[Dan Keaton]

Dear Cees,

I am most interested in the development of 1080p50, 1080p59.94, and 1080p60 cameras.

Many professionals shoot in 1080 for the outstanding images that can be obtained, especially with the nanoFlash.

However, with single-link HD-SDI, no camera can output 1080p60 over the link. Dual-Link or HD-SDI 3G is required.

But, 720p60 can be transmitted over an HD-SDI single link.

Thus, for slo-mo, 720p60 is typically used.

But, again, I am very interested in 1080p60 over dual-link or 3G as then one can shoot in 1080 and have outstanding slow-mo, such as 1080p24 timeline with a crank speed of 60. This is very desirable.

[Rafael Amador]

1080p50/60 has recently been set as standard for 3D filming.
Please don't miss this important document ( the 274M SMPTE/ EBU standard):
http://tech.ebu.ch/docs/tech/tech3299.pdf
rafael

[Dan Keaton]

Dear Rafael,

Thank you for posting that document.

It is a very nice reference document, which emphasis on frame rates used in PAL areas.

[Adam Stanislav]

Originally Posted by Rafael Amador

Please don't miss this important document ( the 274M SMPTE/ EBU standard):
http://tech.ebu.ch/docs/tech/tech3299.pdf

Hmmm... Strange... Page 8, Table 3, Item 2, states:

Y’ = 0.2126 R + 0.7152 G’ + 0.0722 B’

I wonder if it is a typo, or if it truly means R rather than R’. Why would it use the linear value of red (R) but the gamma corrected values of green (G’) and blue (B’).

[Rafael Amador]

You are right Adam; that's a typo on the BT.709 Y' formula..
As Dan points the paper are for PAL-land time-bases, but much on the information can be extrapolated to NTSC-land.
About 1080p60/50, I don't see the need to going there unless you are making Slow-mow for a BIG screen.
The

[Adam Stanislav]

Originally Posted by Rafael Amador

You are right Adam; that's a typo on the BT.709 Y' formula..

Thanks for confirming that.

[Tim Polster]

Dan, just wondering, is 720p120 a possibility for a single HDSDI lane?

Scarlet will have this framerate and it would be quite nice to be able to record using the Nano.

Thanks

[Dan Keaton]

Dear Tim,

I do not know if 720p120 is possible via 1.485 Gbps Single Link HD-SDI.

I will ask our engineers if this is possible with the Sony Codec Module.

It is a very interesting question.

[Tim Polster]

Thanks. Lets hope it is possible.

[Adam Stanislav]

720p120 contains 921,600 pixels per frame. Multiplied by 120 gives us 110,592,000 pixels per second. With three color channels, we get 331,776,000 colored pixels per second. With 8 bits each, we get 2,654,208,000 bits per second. That is slightly more than 2.654 Gb/s. Even without any overhead, 2.654 is more than 1.485.

As far as I know, SD-HDI transfers uncompressed 4:4:4 video. If that is the case, the answer to the question is: No, it is not possible.

[Adam Stanislav]

On second thought, I think it uses 4:2:2, so we need to take 2/3 of that, giving us 1,769,472,000 bits per second, or slightly more than 1.769 Gbps. Still too much.

[Dan Keaton]

Dear Friends,

Do anyone know of a camera that outputs 720p120 via HD-SDI, single-link, dual-link, or 3G?

It is one thing to record internally at 720p120, quite another to send this out via HD-SDI.