Scaffolding for dmabuf zero-copy (plan §9), opt-in via LUMEN_ZEROCOPY:
- src/zerocopy/{cuda,egl}.rs: hand-rolled CUDA Driver-API FFI (no Rust crate
exposes the EGL-interop calls / CUeglFrame) with a shared process-wide
CUcontext + pitched device buffers; an EGL importer (GBM platform on the
NVIDIA render node) that turns a dmabuf into an EGLImage, registers it with
CUDA, and copies it device-to-device into an owned buffer. `zerocopy-probe`
subcommand validates the FFI/linking/GPU access — confirmed on the box
(driver 595, EGL_EXT_image_dma_buf_import + modifiers).
- CapturedFrame gains a FramePayload enum (Cpu(Vec<u8>) | Cuda(DeviceBuffer));
the encoder branches: CPU keeps the expand+upload path, CUDA wraps the device
buffer in an AV_PIX_FMT_CUDA frame fed straight to hevc_nvenc (sharing our
CUcontext via a hand-declared AVCUDADeviceContext, since ffmpeg-sys doesn't
bind hwcontext_cuda.h). open_video/the encoder take a `cuda` flag derived from
the first frame's payload.
The capture-side dmabuf negotiation (which produces the Cuda frames) is the
next step; the CPU path is unchanged and remains the default + fallback. Builds
clean, clippy clean, tests pass.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
The M2 teardown work added an `active` gate to the PipeWire capture callback
(idle by default so reconnects stay cheap, with the stream path calling
set_active(true) on PLAY). The `m0` subcommand was never updated, so its portal
capturer stayed inactive and the callback dropped every frame — `m0 --source
portal` failed with "no PipeWire frame within 10s" on every compositor. Call
set_active(true) before the capture loop.
Validated on headless KWin (Plasma 6.4) via the RemoteDesktop-anchored ScreenCast
session: real desktop frames flow (shm BGRx 1920x1080) and encode to valid H.265.
(Also folds in a rustfmt reflow of the input-test log line.)
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
enricobuehler