At NAB in Las Vegas this year, there were Windows-based systems demonstrated that support the import of really wide ProRes files for content -- typically in the range of 24K+ pixels wide. These are typically used in display systems for stadium LED boards. A local stadium in town here has one that's over 27000 pixels wide (and 64 pixels high). Until now, this task has been performed by the use of legacy uncompressed AVI (raw) formats on Windows. Sidenote: I believe H.264 has an inherent limit of around 9000 pixels due to the internal encoding blocks.
Yet Metal tops out at 16K on the handling of ProRes files. This is due to how AVFoundation shovels video frames onto the GPU directly. This 16k limit on the GPU is documented here ("Maximum 2D texture width and height"): https://developer.apple.com/metal/Metal-Feature-Set-Tables.pdf
I find it very ironic that Apple's own ProRes codec won't support a given pixel size/format and yet that same file is supported on the Windows side. Even the iMacPro won't support it, but a Windows box running the Vega 56 or 64 GPU will.
In short, this lack of very wide video frame support is shuttering an entire demographic of content creators out of using high-end Macs in their workflow. Has anyone else had this issue or can shed some light on the rationale for the 16k limit?
-- bp
