Crate moq_video 

Native video capture, encoding, and publishing for Media over QUIC.

Counterpart to moq-audio for video tracks, and shaped the same way: both split into capture / encode / decode role modules over a shared root Error, with render as video’s fourth. Sits on top of moq_mux (and the hang catalog) and adds the native pieces a desktop/CLI publisher needs.

A raw picture is a Frame wherever it crosses the API: a timestamp and a Surface holding the pixels. Capture and decode produce them, encode consumes them and hands back the compressed encode::Encoded, and Size names a resolution. Keyframes are the encoder’s business: it inserts them per encode::Config::gop, and encode::Encoder::keyframe is there for the rarer case where a caller needs one at a specific frame.

• capture describes a frame source (capture::Config) and grabs frames per platform: AVFoundation/ScreenCaptureKit on macOS, native V4L2 on Linux, native Media Foundation (camera) and DXGI Desktop Duplication (screen) on Windows. capture::Source picks a camera, a display, or (macOS only) a single window or every window of an application; capture::cameras, capture::displays, capture::windows, and capture::apps list what’s available and hand back the ids it takes.
• encode encodes frames with a native backend and publishes them through the matching moq_mux::codec importer, which handles catalog registration and framing. The codec is chosen via encode::Codec: H.264 (openh264 / VideoToolbox / Media Foundation / NVENC / VAAPI) or H.265 (VideoToolbox / Media Foundation / NVENC). Two entry points:
  • encode::publish_capture captures a webcam and publishes it (turnkey). It encodes strictly on demand: the track and catalog are advertised up front, but the camera opens only while a subscriber is watching and is released when the last one leaves.
  • encode::Encoder encodes Frames you supply (from capture, a decoder, or your own pixels via Surface::rgba) and encode::Producer publishes the results.
• decode subscribes to an H.264, H.265, or AV1 track and decodes it to raw frames with a native backend (VideoToolbox on macOS, Media Foundation / DXVA on Windows, NVDEC on Linux, openh264 software fallback for H.264). decode::Consumer is the mirror of moq_audio::decode::Consumer. An NVDEC frame stays in CUDA memory and feeds encode::Encoder::encode zero-copy (the transcode path), scaled in hardware via decode::Config::resize.
• render draws a Frame on the GPU and hands back a wgpu texture to present, importing a GPU frame’s surface directly where the platform allows and uploading I420 otherwise. Behind the non-default render feature, since it pulls in a graphics stack a publisher or relay does not need.

API stability

The public API is codec-agnostic: no public type, signature, or error variant names a backend (openh264 / VideoToolbox / NVENC / NVDEC) or a capture implementation. encode::Encoder takes a Frame, decode::Consumer returns one (CPU I420 on demand, GPU-resident when hardware decoded), and the camera capture path stays internal. So swapping or bumping any backend crate is not a breaking change for consumers. Config structs are #[non_exhaustive]: build them via default()/new() and set fields, so new options stay additive.

The one deliberate exception is Surface, the enum behind every frame. Its variants name platform representations (CVPixelBuffer, Direct3D11, CUDA) so you can render or re-encode a frame yourself without a CPU round trip, which means a major bump of one of those platform crates is a breaking change here. It is #[non_exhaustive] and every variant has a universal fallback in Surface::into_i420, so matching on it stays portable: take the fast path you recognize and let the _ arm handle the rest.

Re-exports

pub use frame::Frame;

pub use frame::I420;

pub use frame::Surface;

Modules

capture

Surface capture. Config is shared; the implementation is per-platform and per-source:

decode

Subscribe to an H.264, H.265, or AV1 track and decode it to raw frames.

encode

Encode captured video and publish it as a moq video track.

frame

Frame: one raw picture, and Surface: its pixels and where they live.

Structs

Size

A frame resolution in pixels.

Enums

Color

Which YUV color space a frame’s samples are in.

Error

Errors returned by moq-video.