MXL — Media Exchange Layer

MXL moves raw frames zero-copy between processes like VDI, but every flow also carries NMOS-style descriptors — format URN, grain rate, colorimetry, components — so MXL streams have standards-grade identity other tooling can see.

Library: libplugin-mxl.so (+ runtime libmxl*.so*) · Implementation: C++ wrapping the MXL C library
Addressing: mxl://…

Configuration

The JSON passed to plugin_open is the flow descriptor:

{
  "id": "5fbec3b1-1b0f-417d-9059-8b94a47197ef",
  "label": "MXL Test Flow, 1080p25",
  "format": "urn:x-nmos:format:video",
  "media_type": "video/v210",
  "grain_rate": { "numerator": 25, "denominator": 1 },
  "frame_width": 1920, "frame_height": 1080,
  "interlace_mode": "progressive", "colorspace": "BT709",
  "components": [
    { "name": "Y",  "width": 1920, "height": 1080, "bit_depth": 10 },
    { "name": "Cb", "width": 960,  "height": 1080, "bit_depth": 10 },
    { "name": "Cr", "width": 960,  "height": 1080, "bit_depth": 10 }
  ]
}

MXL_DOMAIN (env, or a domain path in the host config) selects the shared-memory domain (default /dev/shm/mxl_domain).

Build & notes

Built by plugins/phrame-make.sh (CMake). Stages libplugin-mxl.so plus the libmxl-common.so* / libmxl.so* runtime libraries — the symlink chain must be preserved when copying into consumer images (the orchestrator uses cp -P). Config is parsed with nlohmann::json, which throws on malformed input, so keep config valid — exceptions at the C-ABI boundary are not safe. Note plugin_read_timeout may not be implemented; check before relying on it.