vulkan renderer: Usage of GdkGLTextures slow
As @matthiasc explained on Matrix, the Vulkan renderer is currently downloading GL textures. That's not going to give great performance, especially when one of the GL paths in the GStreamer sink is taken and you end up downloading 30 large textures per second or so.
On Linux on the GStreamer side, applications could work around that by making sure to never use GL and import GL textures as dmabufs, but that requires (platform-specific) application changes and there would be no clear indication to applications why suddenly everything is slow.
On other platforms this leaves people with no alternative right now, other than switching to one of the GL renderers instead.