Three fixes found while running the zero-copy export on real Intel hardware:
- vaapi::create_device() retries LIBVA_DRIVER_NAME in order iHD -> auto ->
i965 -> radeonsi. libva was auto-selecting the legacy i965 driver, which
fails on newer Intel GPUs; the modern iHD (intel-media-driver) is needed.
encoder.rs now builds its hwdevice through this helper.
- vk_device: request the adapter's full limits instead of downlevel_defaults.
Vello's compute pipelines need max_storage_buffers_per_shader_stage >= 5
(downlevel caps at 4), which panicked Vello's shader init on the export
device. This device only ever runs on a real VAAPI GPU.
- ZeroCopyEncoder: unsafe impl Send. It owns its FFmpeg/Vulkan handles
exclusively and is only moved (onto the export thread), never shared.
New workspace crate isolating the unsafe GPU<->encoder interop for
zero-copy hardware video encoding. Every link is validated by a test on
real Intel/Mesa/iHD hardware:
- nv12: GPU RGBA->NV12 compute (BT.709 full-range), byte-exact vs a CPU
reference.
- vaapi: VAAPI hwcontext + h264_vaapi encode (CPU-fed NV12 -> valid H.264),
and DRM-PRIME surface layout probing.
- vk_device: a custom wgpu Vulkan device that adds
VK_EXT_image_drm_format_modifier (+ external-memory fd/dma-buf) via the
wgpu-hal device-from-raw path, so a tiled VAAPI surface can be imported.
- dmabuf: import a VAAPI NV12 surface's tiled DMA-BUF as two aliasing wgpu
textures (Y=R8, UV=RG8) at the plane offsets.
- zerocopy test: render values via Vulkan straight into the VAAPI surface
and read them back 100% correct -- proving the GPU writes into the
encoder surface with no CPU copy.
Not yet wired into the editor; real-frame render + encode-from-surface +
fallback wiring follow. Linux-only (libva); other platforms fall back.
Skyler Lehmkuhl