Gemini 4:4:4 feature request - compressed codecs

[Jim Arthurs]

Originally Posted by Chris Medico

I am VERY interested in knowing the specifics as to why 4.4.4 be used with S-Log vs 4.2.2. The 10bit thing is obvious but why 4.2.2 colorspace is a problem is not so obvious.

Hi Chris, I've been doing some recording with a Gemini prototype and can add my two cents...

Since the F3 S-Log mode doesn't allow electronic white balancing or color correcting beyond either the 3200K or 5600K CC choices, you will always be doing a grade on the S-Log imagery, both for contrast and for color balance. 444 should give you the best possible chance of doing these wider balance adjustments.

Secondly, the F3 might be the first camera with a 444 option, but it won't be the last. While there is debate on how valid the ultimate 444 of the F3 is, since it starts from relatively lower pixel count bayer source, no question each future camera will build on this until 444 is a pretty standard and required method of recording. My nanoFlash from Convergent has kept my Sony EX1 "happy" and very current for the almost 4 years I've had it... longer than ANY other video camera I've owned. I'm certain the Gemini will keep the F3 as current as the nanoFlash has kept the EX1 for as many years, and be ready for any other future 444 cameras.

Finally, uncompressed is NOT the way I'll edit. But, and this is the important part, the original .dpx files are a way to put off any decision making ABOUT post until you're IN post. You can delay any decision to compromise the imagery the camera can make until you are ready to edit, or your client has decided how it will be posted.

Regards, Jim Arthurs

[Billy Steinberg]

Secondly, the F3 might be the first camera with a 444 option

The Sony F900 and the Sony 1500R with the CineAlta option have been 444 capable for quite a while... (Both are 3 chip, and hence no bayer filter).

Billy

[Jim Arthurs]

Correct, and other high end cameras (Viper, etc.)...

...I meant to say "Prosumer", as I still think the F3 qualifies as, based on build quality and form factor... I wonder what next, and from what manufacturer will go this route at equal or lesser price point...

Regards,

Jim Arthurs

[Alister Chapman]

There are quite a few reasons why you want to record 4:4:4 from the F3 in particular.

As has been said when using S-Log you can only choose 3200k or 5600k so colour correction will be the norm, so getting every last drop of colour data you can squeeze out of the camera is desirable.

The other issue is that to get 4:2:2 S-Log out of the F3 requires that you use the Monitor Sdi output to feed the recorder. With S-Log enabled you only get 4:4:4 out of the dual link ports, there is no 4:2:2 S-Log from these connectors. While that in itself is not an issue, the quality of the 4:2:2 on the monitor SDI appears to be full quality... the issue is that you then can't use the cameras built in Look Up Tables as these would be applied to the SDI monitor out. So on-set you have no way of seeing the full recording range unless you use an external device that can apply a LUT and this complicates things, especially on location.

Chris mentioned using a proxy workflow as a way to help deal with the large files that the Gemini will create. This is one of the great things about the F3 4:4:4 workflow. You can record the uncompressed 4:4:4 S-Log (or standard gamma) on the Gemini while recording 35Mb/s 4:2:0 proxies in the camera. The proxies can have a Look Up Table applied while you shoot so that the off-line can be done with images that approximate the final look of the programme. Any time coded preview footage can be copied from the in-camera proxies that look half decent, unlike the S-Log which will often put producers and those that don't understand the workflow into a panic believing the shots are incorrectly exposed.

I think Chris has some valid points. The Gemini won't suit everyone, that's why CD will continue to sell the NanoFlash, which is still a class leading device thanks to it's use of the broadcast industry standard XDCAM HD codec. This means you can dump files from the NanoFlash directly onto Optical Disc for long term storage or archive.

I've used uncompressed, ProRes, CineForm, DNxHD over the years. They all perform well. Yes there is a storage overhead for uncompressed, but one thing that does get overlooked is that the processing requirements for uncompressed are lower than for a compressed codec. Provided your data pipe is fat enough, working with uncompressed is actually quite easy and fast unless your working with multiple layers in which case data throughput can become an issue. I'm still trying to figure out what my "real" SSD requirements will be. Yes I will need to spend some money on storage, but just 4 years ago I was spending close to $8000 USD for 25 mins of storage. The original 8Gb SxS cards cost almost that when the EX1 was launched. Today I own enough SxS cards to shoot non stop for 10 hours. I see the same happening with SSD's.
I'm very excited about being able to capture the pristine output from the F3 without added artefacts or encoder noise.

[Chris Medico]

Originally Posted by Alister Chapman

There are quite a few reasons why you want to record 4:4:4 from the F3 in particular.


The other issue is that to get 4:2:2 S-Log out of the F3 requires that you use the Monitor Sdi output to feed the recorder. With S-Log enabled you only get 4:4:4 out of the dual link ports, there is no 4:2:2 S-Log from these connectors. While that in itself is not an issue, the quality of the 4:2:2 on the monitor SDI appears to be full quality... the issue is that you then can't use the cameras built in Look Up Tables as these would be applied to the SDI monitor out. So on-set you have no way of seeing the full recording range unless you use an external device that can apply a LUT and this complicates things, especially on location.

Alister, I would like to offer some info regarding the signal possibilities of the F3.

4:2:2 is available on the A/B SDI ports of the F3 with S-Log enabled. You can either set the output to 4:2:2 @ 1.5G + S-Log in the menu OR if you set the camera to 4:4:4 @ 1.5G + S-Log each SDI port outputs a 4:2:2 signal which when combined equal the 4:4:4. {Edit - I will be checking to see if one half of the 4:4:4 is a valid and recordable 4:2:2 signal. According to the specs in the manual it is but this will be my first opportunity to test it.}

With this you have the flexibility to record 4:4:4 S-Log OR 4:2:2 S-Log to your recorder and still use the internal media + LUT and MONITOR + LUT.

If you select 4:4:4 @ 3G + S-Log you will only have a signal on SDI (A) and no option for 4:2:2 except on the MONITOR port.

I'll be testing out one of the PIX240 recorders this weekend. I'll be happy to demo a Gemini as well when they are available. ;)

[Peter Moretti]

Originally Posted by Alister Chapman

...

As has been said when using S-Log you can only choose 3200k or 5600k so colour correction will be the norm, so getting every last drop of colour data you can squeeze out of the camera is desirable.
...

Is this the case w/ all Sony high-end cameras? As it can be quite difficult to accurately dial-in WB in post, esp. when dealing w/ mixed lighting sources.

[Chris Medico]

Peter,

Shooting a grey card will help with that. I have one attached to the back of the slate so when I roll camera I shoot both sides of the slate. The slate also has some color chips along the top. I don't take them as gospel for accuracy but it does help to have something you know is constant to reference in every shot.

[Jim Arthurs]

This was my good friend shooting film, it's now my good friend with the F3/S-Log combo... roll a few frames on this for every lighting setup change as an industry standard reference...

KODAK: Gray Cards

Regards,

Jim Arthurs

[Alister Chapman]

Originally Posted by Chris Medico

4:2:2 is available on the A/B SDI ports of the F3 with S-Log enabled. You can either set the output to 4:2:2 @ 1.5G + S-Log in the menu OR if you set the camera to 4:4:4 @ 1.5G + S-Log each SDI port outputs a 4:2:2 signal which when combined equal the 4:4:4. {Edit - I will be checking to see if one half of the 4:4:4 is a valid and recordable 4:2:2 signal. According to the specs in the manual it is but this will be my first opportunity to test it.}

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.

[Chris Medico]

I called Sound Devices today and they confirmed that they don't do RGB so the PIX240 is not compatible with S-Log from the F3.

That is a disappointment.

[Alister Chapman]

RGB only works over dual link or 3G HDSDi so if you want to use the A/B connectors you will need a DualLink or 3G recorder and there are not many choices. For a portable unit there is the The Gemini or Cinedeck, for a luggable device there is the Weisscam DM-2, Codex, Sony R1 or R4 and the DigiDisk (there may be others). All of these are more expensive than the Gemin, all are much larger, all are heavier, some ridiculously so.
If your not in the field then a Mac or PC with a DualLink Blackmagic or AJA card is also an option.

Of course you can still get S-Log 4:2:2 YCbCr out of the Monitor HDSDI output, but as I said you then loose the ability to record proxies with a LUT applied and monitoring with a LUT direct from the camera. Adding a Blackmagic HD-Link would sort out the monitoring LUT's but it's an extra piece of kit to lug around and power etc.

[Chris Medico]

Based on the current state of recorders I've decided to continue to use cinegamas and hold off on purchasing anything till things settle out more.

No doubt with more cameras coming out with these capabilities, recorders will continue to evolve.

[Chris Medico]

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.

The exact makeup of the RGB flavor of the interface wasn't easy to find. I finally found a good writeup on it in a whitepaper on the Sony HDCamHR (go figure).

I know this may be slightly OT but I wanted to share what I read and now understand about what the F3 outputs when in RGB mode.

When in RGB Dual Link 4:4:4 mode SDI (A) consists of a full rez "G" and even numbered scan lines of "R" and "B". This is in effect "A" 4:2:2 signal but not a usable one. SDI (B) transmits a 0:2:2 signal that consists of NO chroma and the ODD lines of "R" and "B".

This is a description of the video payload itself and there are lots of other things going down the pipe too such as timing packets and the audio streams.

When in 3G mode the entire signal is sent down one cable exactly as a 4:2:2 signal would be but with the extra addressing in the stream for the extra chroma info.

Anyway, Thanks for the patience guys. I think I'm up to speed on it now.

[Alister Chapman]

... and HDCamSR is 12 bit with the extra 2 bit's in a separate stream on "B" AFAIK. The F3 is 10 bit only. The issue is that the 4:2:2 is RGB not the more normal YCbCr. As there is no standard for HDSDI 4:2:2 RGB it is unusable with current devices.

[Ed David]

Alister and Dan,

Thank you.

You convinced me to go Gemini. And also the S Log out from the F3 as well did. The workflow won't be too complicated. I will have a DIT on set during Gemini shoots. Who will get a drive (256gb ssd at this point) - and on set convert it to PRO RES 444.

The more and more I shoot with S Log - the more I need to color correct the images better and also this way - I am assuming this is correct - I can use the Gemini to get 60 FPS 1080p out of the Sony F3? Please tell that's true. Because I miss overcranking.

Also I can start to use the Gemini on Red Epic and Arri Alexa shoots as a system to get well for the Red Epic - footage that's already 1080p and good enough for web work ? Correct? For the Alexa, it would give me longer recording times than going to the 32gb card. Again how does that sound?

I love my Nanoflashes - I own 3. They are the most reliable recorders I've ever had and look forward to the Gemini.