NVK Gains Vulkan Video Support: H.264 Decoding Now Works in Mesa 26.3

The first implementation of Vulkan Video support in the open-source NVIDIA driver known as NVK has been merged into the Mesa 26.3-devel development branch. For now, this means hardware video decoding in the H.264 format — the first working result of years of effort on this subsystem.

Why it took so long

Bringing Vulkan Video to NVK took a good while, for several reasons at once. First, a significant portion of NVIDIA's hardware video acceleration logic had to be studied through reverse engineering. Second, the implementation is written in Rust, so the developers had to wait for the necessary Rust driver infrastructure to catch up.

What already works and what doesn't

Work was also done on H.265 decoding, but in its current state it “hangs” the graphics chip's system processor (GSP) on NVIDIA cards, so the only usable decoder for now is the H.264 one. It is precisely because of this dependency on the GSP that Vulkan Video support in NVK is limited to Turing-architecture cards and newer.

There is also a requirement on the kernel side: the NVK user-space driver relies on a Nouveau patch that landed in Linux 7.3. Without it, the open-source stack won't be able to use Vulkan Video on top of NVIDIA's NVDEC hardware block.

Timeline

The stable Mesa 26.3 release is expected in the fourth quarter — roughly in November, around the same time the stable version of Linux 7.3 should ship. For those who want to try the new feature sooner, the merge description itself includes instructions for building Mesa with NVK Vulkan Video support enabled.

The arrival of this capability is a notable milestone for NVIDIA's open-source graphics driver stack, which is gradually closing the functional gaps compared with the proprietary solution.

Source: Phoronix