Apple released a new codec this summer with updates to its video apps, Apple ProRes 4444 XQ. Arri decided to include ProRes 4444 XQ as a recording option in the ALEXA XT & XR. The codec isn’t available in Adobe and most other QuickTime-aware apps, but you can manually install it for general use with or without installing Final Cut Pro X 10.1.2.
The new codec is designed for cameras that record High Dynamic Range (HDR) video, providing a more efficient storage alternative to uncompressed 16-bit float files. Apple discussed ProRes 4444 XQ in a new White Paper on ProRes, which has lots of extra details and benchmark comparisons. They say:
The highest-quality version of Apple ProRes for 4:4:4:4 image sources (including alpha channels). This format has a very high data rate to preserve the detail in high-dynamic-range imagery generated by today’s highest-quality digital image sensors. Apple ProRes 4444 XQ preserves dynamic ranges several times greater than the dynamic range of Rec. 709 imagery.
This holds true even against the rigors of extreme visual effects processing in which tone-scale blacks or highlights are stretched significantly. Like standard Apple ProRes 4444, this codec supports up to 12 bits per image channel and up to 16 bits for the alpha channel. Apple ProRes 4444 XQ features a target data rate of approximately 500 Mbps for 4:4:4 sources at 1920×1080 and 29.97 fps. ProRes 4444 XQ is supported on OS X Mountain Lion v10.8 or later.
A few months earlier, Red Deer City TV showed how to copy the codec from a FCP X install package contents and make it available in Adobe Premiere and After Effects. It’s the same process if you just have the trial download. Here’s Magic Lantern Raw to ProRes 4444 XQ with After Effect CC Adobe from Red Deer City TV.
In January 2016, David Torcivia shared Decoding Prores 4444 Xq On Windows, explaining that decoding works if you change the file’s FourCC (or four-character code) tag, via a utility or with an ffmpeg command. VirtualDub’s Hex editor should also work.