VA-API driver backends

A VA-API backend implements the interface for a supported device and driver stack, so loader selection, hardware identity and backend capabilities determine the usable media path.

A VA-API driver backend implements VA-API calls for a supported device and software stack. Libva provides the interface/loader layer; the selected backend provides device-specific acceleration behavior.

This separation explains why having libva installed is an earlier condition than successfully decoding a chosen video.

Identify each layer

Layer Fact to preserve
Application Interface/build and operation it requests
Libva API and backend-loading layer
Backend Selected implementation and version
Device/driver stack Actual adapter and exposed kernel/device context
Media operation Profile, entrypoint, format and dimensions

A capability report belongs to that combined context. A profile list copied from another machine is not a query of this backend/device pair.

Intel backend names are implementation names

Intel's current Media Driver repository uses the iHD backend name. Its earlier Intel VA-API driver uses i965 and is now archived.

Name Relevant role
iHD Intel Media Driver backend
i965 Earlier Intel VA-API backend project
HEVC Main 10 A codec/profile configuration
VAEntrypointVLD A selected decode entrypoint

The backend names are not codec formats or universal generation labels. Their supported products and operations belong to their documented implementations.

Intel's current repository describes LIBVA_DRIVER_NAME and driver-search-path configuration for its stack. Those settings influence selection; they do not manufacture support for hardware outside that implementation.

Device paths identify access points

A Linux render-node path such as /dev/dri/renderD128 identifies a device access node in that environment. The numeric suffix is not an Intel, AMD or NVIDIA model specification.

The process must open the intended node and use its compatible backend. Which adapter it denotes should be established from the system's device information rather than inferred from “128.”

No device node was opened for this article.

Process context is part of a comparison

An interactive diagnostic and Emby Server's process can have different environment, library search, device access or selected adapter context.

A successful report from one context establishes its result. Comparing it with another process requires retaining those selection and access facts.

See Also

References