pixeldestrukt

work prototype

dan-mx

A lighting protocol for pixel-dense LED displays on IP networks. Variable-size frames, per-frame compression, and color encoding that follows what the eye can see.

Status
prototype
Year
2026
Stack
Python, C++17, ESP32, UDP
Repo
github.com/pixeldestrukt/dan-mx

What it does

DMX's 512-byte universe was designed for 1986-era RS-485 wiring, and Art-Net and sACN wrap that same frame in UDP. dan-mx starts from the other end: what would a lighting protocol look like if it were designed for gigabit Ethernet, cheap microcontrollers with DMA, and human vision?

  • No universe ceiling. A frame addresses whatever range of pixels the sender wants to update.
  • Compression chosen per frame. The encoder tries RAW, pixel-level RLE, and DELTA (XOR against the previous frame, then RLE) and sends the smallest. A one-pixel change in a noisy 100-pixel frame goes from 214 bytes to 23.
  • Color in the protocol. Each frame declares its transfer function (linear, gamma 2.2, sRGB) and its channel packing, including a G6R5B5 mode that gives green the bits it deserves.
  • Disposable frames. UDP for frame data, multicast for groups. A dropped frame is replaced by the next one; a keyframe interval caps how long a receiver that missed a delta can stay out of sync.

Frame

A fixed 14-byte big-endian header, then the body:

 offset  size  field
     0    4B   magic "DMX2"
     4    1B   version
     5    1B   flags
     6    1B   encoding     (RAW, RLE, DELTA)
     7    1B   color_space  (RGB888, RGB565, G6R5B5, RGB888_LINEAR)
     8    1B   transfer     (LINEAR, GAMMA_22, SRGB)
     9    1B   seq
    10    2B   start_pixel
    12    2B   pixel_count

Status

Two reference implementations, byte-compatible with each other: a Python sender and receiver with 33 tests, and a heap-free C++17 decoder for the ESP32 with an example that drives a WS2812 strip through FastLED. Delta encoding, keyframe recovery and perceptual packing work. Dithering, palette mode and gradient runs are next, and multi-receiver sync and discovery are open questions.