Build the full end-to-end zero-copy encoder, validated on Intel/VAAPI:
- render_nv12: fragment-shader RGBA->NV12 that renders luma/chroma into
the imported R8/RG8 plane render targets (compute storage can't write
the DMA-BUF-backed planes; render attachments can).
- dmabuf: import_raw imports an NV12 DMA-BUF by explicit layout; the two
plane images + shared memory are now destroyed by wgpu via texture_from_raw
drop callbacks (Arc MemoryGuard frees the memory once both images are
gone, in wgpu's wait-idle'd deferred pass) -- fixes the teardown segfault.
- encoder::ZeroCopyEncoder: renders an RGBA texture straight into a pooled
VAAPI surface (imports cached by VASurface id) and encodes with h264_vaapi.
encode_rgba + finish; the caller renders on device().
Tests: real-frame render into the surface matches the CPU NV12 reference,
and a 30-frame encode produces valid H.264 (ffprobe-verified) with clean
teardown. Not yet wired into the editor.
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