As many suspected, Sony’s new AXS-R7 Recorder does a lot more than 4K RAW, full resolution 120p recording, and 30 second caching. Why else would it be larger than its older brother, the R5?
The big news is X-OCN.
In addition to 16-bit linear RAW, the AXS-R7 will record Sony’s new 16-bit X-OCN format. X-OCN stands for eXtended tonal range Original Camera Negative. Think of it as a camera negative that comes in a smaller digital film can. Like RAW, it retains everything the sensor sees. Unlike RAW, it promises lower bit rates and greater ease of use.
What is X-OCN?
X-OCN is the AXS-R7 recording format that uses a new Sony algorithm specifically formulated for the F5 and F55 sensors. X- OCN produces file sizes much smaller than camera RAW, resulting in longer record times, faster file transfers and more economical postproduction — while retaining the quality of 16-bit linear encoding.
Sony’s AXS-R7 records two versions of X-OCN: Standard and Light. They are both available in 2K and 4K, at frame rates of up to 120p. X-OCN ST (Standard) is visually indistinguishable from Sony’s camera RAW. X-OCN LT (Light) is intended where lower data rates and smaller file sizes are desirable.
How do X-OCN and RAW differ?
RAW is unprocessed image sensor data. X-OCN is processed and optimized for the individual sensor qualities of the F5 and F55.
Sony F55 RAW is 16-bit linear. What is X-OCN?
X-OCN is also 16-bit. Of course, 16-bit color space exceeds what the human eye can distinguish.
Why do we like 16-bit?
It preserves the maximum latitude of the image sensor, offering the widest possibilities in post-production — particularly 16-bit ACES and HDR color grading. (You can try this at home in Photoshop if you have 16-bit images by toggling Edit-Image Mode: 8-bit or 16-bit.)
Why did Sony create X-OCN?
Peter Crithary manned the midnight FDT tech support hotline with these answers.
“Quality. Sony tests concluded that X-OCN ST is visually indistinguishable from F55 RAW. It is no small achievement. X-OCN combines full 2K and 4K resolution with extraordinary color reproduction, well suited to Sony’s S-Gamut 3. In particular, 16-bit scene linear tonal gradation retains the camera’s full dynamic range, with far greater capacity for visual expression than 10-bit or 12-bit digital formats.
“Smaller files. X-OCN results in smaller file sizes than RAW. At the highest 4K picture quality, X-OCN ST has 40% longer recording time and roughly 30% shorter file transfer time than Sony’s F55 RAW. The advantages for X-OCN LT are greater still: 142% longer recording time and roughly 59% shorter file transfer time. Furthermore, X-OCN is an appropriate recording format for HDR production since it keeps maximum dynamic range with smaller data size.
“Post flexibility. As with F55 RAW, X-OCN records metadata about your selection of ISO sensitivity, color temperature and so on. These choices are completely non-destructive and the full potential of the original sensor data is delivered into postproduction. The colorist and editor are empowered with far greater decision-making flexibility than is possible with even Log-encoded video.”
What X-OCN resolutions and frame rates are supported?
The R7 Recorder supports 4K (4096 x 2160) and 2K (2048 x 1080) X-OCN recording, up to 120 frames per second. The same compression ratio is maintained at all frame rates; compression is not increased as fps rate increases.
What media records X-OCN?
You can use Sony AXS Memory A series S24 media (slim cards, blue trim, up to 2.4 Gbps write speed) in capacities of 256 GB, 512 GB and 1 TB. The new A series S48 media (slim cards, black trim, up to 4.8 Gbps write speed) is required for 4K 120p recording. (4K 120p is only available with PMW-F55 camera.)
The bit rates of 4K XAVC Class 480 (480 Mbps at 30p) and 4K X-OCN LT are about the same. How do they differ in look?
16-bit X-OCN LT delivers better tonal quality, in general, than 10 – bit XAVC recording. XAVC Class 480 was developed to give an extra boost to picture quality with certain types of scenery. If you do not have an AXS-R5 or AXS-R7 recorder, you can still take advantage of a higher bit rate option for on-board recording. Also, if you want or need a smaller camera package (without R5 or R7), the new XAVC480 profile and level give you an additional option.
Can you do cache recording with X-OCN on the AXS-R7?
Yes. You get about 30 seconds of 4K 24p cache recording in X-OCN ST mode. Other cache recording times vary by frame rate and resolution.
What file wrapper does X-OCN use?
X-OCN format interleaves audio and video in a single, simple file. It is the same, standardized MXF data structure that Sony has used for XAVC, Sony RAW, SR File and MPEG HD formats.
Can the F5 and F55 record X-OCN onto internal SxS cards?
No. X-OCN is only available with the new AXS-R7 recorder and AXS A series memory cards.
What grading and post production software supports X-OCN?
Peter Crithary said, “Sony is in discussion with the alliance companies that support F55 RAW and the XAVC codec. Of course, actual support announcements will come from each individual vendor.”
“Sony’s RAW Viewer will be updated to support X-OCN when the AXS-R7 launches in September. RAW Viewer will support X-OCN playback and trimming of X-OCN files based on imported EDLs. RAW Viewer supports both Windows and Mac OS.”
Off the record, it already looks like the major players are at work implementing X-OCN — including DaVinci Resolve, Baselight, Colorfront OSD and Sony Raw Viewer.
And now for the specs!
There are two recording modes:
X-OCN ST (Standard) and X-OCN LT (Light). Sony’s tests reveal that X-OCN ST is visually indistinguishable from F55 RAW. But X-OCN ST captures 4K 24p at just 661 Mbps, a 30% reduction compared to F55 RAW.
X-OCN LT is intended where lower data rates and smaller file sizes are important, while it maintains powerful grading flexibility.
X-OCN LT records at 389 Mbps in 24p, a 59% savings over F55 RAW.
AXS Series memory cards
New, slim AXS A Series memory cards (A1TS48 and A512S48) come in 1 TB and 512 GB. They are identified with black trim, and have data rates up to 4.8 Gigabits per second. Use these for longer record times and shooting 4K RAW 120 fps.
Existing A Series S24 cards (blue trim, 1 TB, 512 GB and 256 GB capacity) also fit the AXS-R7, but only record up to 60 fps 4K RAW.