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What exactly is X-OCN?

alisterchapman
Top Contributor

I was chatting with some potential VENICE users last week and I became aware that they really weren't sure what X-OCN is. One particular comment that was made was "I'd rather have a raw camera than one that uses a codec" which made me think about whether some people really understand what codecs are and in particular what X-OCN is.

A codec is a "Coder - Decoder". Basically any system that takes a signal, turns it into code that can be recorded and then at the other end de-codes the file so it can be played back again. Even uncompressed video will involve a codec as the codec defines the way the uncompressed video should be recorded and then played back.

X-OCN is a codec, but then every other type of raw format uses a codec of some form. So in this regard X-OCN is not different from other types of raw. 

X-OCN stands for eXtended tonal range Original Camera Negative. A bit of a mouthful! But in essence X-OCN is little different to raw. It takes the output of the cameras sensor, encodes it in a 16 bit file preserving as much as possible of the original information from that sensor. The image is not processed in camera, instead just like other raw formats all the image processing including de-bayering is done in post production. Alongside the video data information about the cameras settings, things like the white balance, EI and ISO are saved as metadata and these values are used in post during the decoding to determine the brightness and colour temperature of the footage once it has been de-bayered. But, you can override this metadata in post to decode the material brighter or darker or with a different colour temperature using slider type controls for ISO and WB as well as controls for the sharpness, highlight and shadow ranges. 

So, the reality is that X-OCN behaves exactly the same as any other raw format, it is not different.

There are 3 quality levels. X-OCN XT, ST and LT. All are suitable for mainstream production and offer exceptionally high quality. The standard version is X-OCN ST. XT offers less compression for the most demanding of applications and LT is more highly compressed for those times when storage space may be at a premium. When I've tried to find differences between them all I have really struggled. With highly detailed and highly textured images if you look hard enough with side by side content you might spot some very minor softening of X-OCN LT content compared to XT, but you really have to look hard and it's not nasty in any way. I don't think anyone would ever notice this in the final output and personally I find X-OCN LT to be a very nice format to work with, especially at higher frame rates or resolutions where storage space may be a concern.

X-OCN files are very compact. For the same resolution, the 16 bit X-OCN ST files are a little smaller than 10 bit ProResHQ files. You can shoot  8K X-OCN LT and the files are no bigger than 4K ProRes 444XT.  So those thinking of shooting 8K with VENICE 2 need not worry that the files will be unmanageable. X-OCN is also very easy to decode and work with in post production. I can edit and grade VENICE 2 8K content on my MacBook Pro laptop.

Alister Chapman
Cinematographer/Producer/Trainer
2 REPLIES 2

DougJensen
Leading Creator

I'll give another thumbs up for X-OCN.  I've been shooting with it for quite a few years already with my F55/R7 and it is, by far, my favorite codec.  It looks great and grades out nicely in Resolve.  Sometimes I use ST and sometimes LT, but I almost never bother shooting pure RAW anymore.  I only wish it was an option on all my other cameras.

julienjarry
Top Contributor

This is really great Alister, thank you.