What is XOCN? Why is it so good, why do we need it?

advertise-here-275 What is XOCN? Why is it so good, why do we need it?

This time last year I was just starting to earn about a new codec from Sony called XOCN (eXtended Original Camera Negative). XOCN is currently only available with the Sony F5/F55 and the new AXS-R7 raw recorder. Sony’s original R5 raw recorder takes 16 bit sensor data and applies a very mild amount of compression before recording the sensor data as linear raw. I have never seen any compression artefacts when using the 16 bit linear raw and it really is an amazing format to work with. So much so that I will always use it whenever possible.

But now as well as 16 bit linear raw the R7 can record 16 bit linear XOCN. Now, I’ll be completely honest here, I’m really not sure what the difference is between raw and XOCN. As far as I can tell XOCN is very, very similar to raw but sufficiently different to raw to avoid infringing on patents held by other manufacturers for compressed raw. XOCN is more highly compressed than Sony’s raw, but in every test I’ve done I have found it hard to spot any compression problems or any significant difference between XOCN and the original 3:1 raw.

So, I hear you ask…. “If it’s really that good what don’t we just do away with XAVC and use XOCN?” Well that is a good question. It all depends on processing power. XAVC is a traditional codec so inside the codec is a normal video image, so the only thing a computer has to do to play it back is uncompress the codec. XOCN is a compressed wrapper that contains sensor data, in order to view the image the computer has to uncompress the data and then it has to construct the image from the data. So you need a really good graphics card in a decent computer to work with XOCN. But if you do have a decent edit or grading workstation you should find XOCN straight forward to work with, it doesn’t require specialist cards to accelerate the decoding as Red raw does.

The key benefit that XOCN brings over traditional video is that it is 16 bit. 10 bit video is pretty good. In a 10 bit video you have almost 1000 tonal values, not bad when you consider that we have been using 8 bit for decades with only 235 shades. But 16 bit brings the potential for a whopping great 65,535 shades. This starts to make a big difference when you are extensively manipulating the image in post production. Any of you that are in to photography will know that you can push and pull a 16 bit raw photograph far, far further than an 8 bit jpeg. 16 bit video is no different.

But what’s really amazing about XOCN is you get almost all the benefits of linear raw but in a file size smaller than the same resolution 10 bit ProResHQ. If you use XOCN-LT the files are roughly half the size of ProResHQ. This means your media lasts a sensible amount of time and backups, transfers and archiving are all much easier, much faster than with uncompressed raw. Sony’s 3:1 compressed raw from the R5 has always been pretty easy to deal with. XOCN is even easier. Using XOCN-LT you can squeeze well over 2 hours of 16bit 4K on to a 512GB AXS card! In fact the file sizes are only marginally larger than XAVC class 480.

xocn-data-rates-1024x276 What is XOCN? Why is it so good, why do we need it?

The reduction in data rates becomes really significant if you shoot at high frame rates. As 50p and 60p productions become more common XOCN allows production companies to shoot 60fps with the benefits of 16 bit data but with files sizes barely any bigger than 24fps ProResHQ. If you have a Sony PMW-F55 you can shoot at 120fps in 4K using XOCN and the files are twice as big as 24fps raw.

For further information on XOCN please take a look at this page from Sony, it’s very informative and has a very good example of why 16 bit data is important, especially if you are shooting for HDR.

https://pro.sony.com/bbsc/ssr/show-highend/resource.solutions.bbsccms-assets-show-highend-f55xocn.shtml

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2 thoughts on “What is XOCN? Why is it so good, why do we need it?”

    1. I really very much doubt it. Several problems: The camera would need to pass 16 bit data down the SDI instead of the current 12 bit. I suspect that is well beyond what a single SDI can take. Then you would need to see an update to the IFR5 and compatibility between the IFR5 and AXS-R7 which does not currently exist.

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