Gemini 4:4:4 feature request - compressed codecs

[Jim Arthurs]

Until I did some tests with the Gemini on Sunday, I had assumed the best way to work with F3 S-Log was to simply get used to the way the flat S-Log looks under different conditions and do a mental adjustment. I think it's easy enough for us shooter types to figure that out. Of course, add a client, or art director, or anyone else into the mix and you suddenly need correction.

So, doing some run and gun work, I decided to turn on the F3 LUT (rec709 800%) and see what it would be like to use the LUT in combination with zebras at 100% as the main basis for making exposure decisions for S-Log. I then would glance at the Gemini LCD panel for a "confidence" view of the flat S-Log whenever I was concerned. This proved a great combination.

I found that using the LUT allows a greater deal of predictable headroom, as you make the choice on highlight exposures, assured that you have a good deal of recoverable headroom beyond where your viewfinder/zebra is telling you there is clipping. My analogy is with the painted lines on a highway; You might not need the lines in order to drive down the road, but the lines make it easier to stay in the proper lane, and keep your tires out of the ditch!

Here are some split screen examples, taken on Sunday. Very high contrast, shadows and shade. All at 3200K. Upper left image is the on-board 35Mb/sec with the cameras burned in LUT. Upper right is the un-doctored S-Log. Bottom left is a grade to show what picture information is still available in the image high lights. And Bottom right is a more or less "normal" grade...

http://ftp.datausa.com/imageshoppe/o..._QUAD_VIEW.jpg
http://ftp.datausa.com/imageshoppe/o..._QUAD_VIEW.jpg
http://ftp.datausa.com/imageshoppe/o..._QUAD_VIEW.jpg

And here is a zip of the Gemini's .dpx files from each if you want to play with S-Log...

http://ftp.datausa.com/imageshoppe/o...X_EXAMPLES.zip

The Gemini will let you take this one step more... add video village to the mix. You will be able to set up a completely different LUT for the Gemini's HD-SDI or HDMI output, giving you a three point viewing method;

-On camera LUT tailored to exposure
-Flat S-Log "confidence" on the Gemini monitor
-A conventional "beauty" viewing LUT for Video Village.

All of this from a single package the size of a SmallHD DP6, powered by the camera's Swit-style battery with a D-Tap that records 4:4:4.

Regards,

Jim Arthurs

[Billy Steinberg]

Originally Posted by Alister Chapman

Sadly it's not that simple. One half of 4:4:4 RGB is not 4:2:2 YCrCb. You can't just take one leg of a dual link 4:4:4 RGB output and use it as 4:2:2, you will be missing half your colours.

The S-Log output options are:
1.5G RGB 444 & S-Log -- AKA dual link, both A and B used for RGB
3G RGB444 & S-Log -- AKA Single link RGB

All the other options are not S-Log, so the only way to get 4:2:2 YCbCr S-Log out of the camera is via the monitor HDSDi.

The output options are interesting as if you select 1.5G + Video and set the camera to 50i or 60i the output on the A/B connectors is 50/60P.

I don't have time now to read the manual, so I don't know if there's an RGB<->YCbCr conversion built in as well, but for converting 3G (or dual-link) to/from "1G/1.5G" you can check out this offering from AJA. I also didn't check out how much it costs...

3GM Product Page
3GM Product Manual (pdf)

Billy

[Alister Chapman]

The AJA box is certainly an option for taking the 3G or dual link RGB and converting it to single link 4:2:2 YCbCr. I wonder how good the colour space conversion is?
It's another box to attach somewhere, more cables and power. I'd rather take the non-LUT 4:2:2 out from the monitor out direct from the camera to the recorder. Then feed the Dual Link or 3G into a Blackmagic HDLinkPro box and apply the viewing LUT in the HDLink. That way I have the bare minimum of devices, cables and connectors between camera and recorder yet still have a monitor out with LUT, plus I can feed both an HDSDI and HDMI or DVI monitor from the HDLink.

Either way it's still a lot more complex and fiddly than a dedicated 4:4:4 recorder.

[Gints Klimanis]

To state the obvious, a new CD machineis wanted : one that can compress 4:2:2 or 4:4:4 and write to an SSD. Hopefully, CD is already working on this.

The flash solution becomes expensive quickly as top quality flash that can record 60 minutes of 280 Mbps I-Frame is about $1000/128 GB (Sandisk Extreme Pro). I recently shot a sporting event with EX1 = Nano and covered it in 50 Mbps MPEG-2 LongGOP because of the flash cost issue. I'd gladly pay $500-1000 more for a Nanoflash with SSD storage. There would be some hesitation in buying a device that doesn't handle 1080p60 or whatever the next iteration of HD will include. 720p120?

[Dan Keaton]

Dear Gints,

1. Stay Tuned!

2. The Axtremex 128 GB 600x CompactFlash cards are available for $489.95 at nanoFlash.net .

These have been very thoroughly tested in the nanoFlash.

[Cees van Kempen]

Dear Dan,

Can you give an indication of when a radio signal can be expected for the ones staying tuned?

I fully agree with Gints, 1080p60 is what I am looking for, too.

Dan, can you give information about this issue I asked on the FS100 forum: does the FS100 output 1080p60 for in case external recorders arrive that can deal with it?

[Dan Keaton]

Dear Cees,

We are aiming for next week.

I am not being coy or attempting to hype this; doing this right requires permission and licensing from other companies. We cannot announce until everything is in place. Then we will announce our plans.

From reading the Sony FS100 manual it seems like 1080p50/1080p60 is available from the HDMI output.
But, we have not tested this, so this is a great question for Sony.

Since this is thread is a request for a compressed codec, please note that recording 1080p60 in any of the commercially available codecs is a major task.

This is one of the things that one does not really know if it is possible until one actually does it.

.

[Cees van Kempen]

dear Dan, Thanks for your clear reply.

[Gints Klimanis]

Originally Posted by Dan Keaton

2. The Axtremex 128 GB 600x CompactFlash cards are available for $489.95 at nanoFlash.net .

Thanks, Dan. I may spring for those, but your site states the 128GB version tops out at 220 Mbps.

[Dan Keaton]

Dear Gints,

The Axtremex 128 GB CompactFlash cards are about to support 280 Mpbs in the nanoFlash.

Please allow about two weeks for this to come true.