led-matrix-zmq-server

A tool for interacting with rpi-rgb-led-matrix over ZeroMQ.

Looking for the ye olde version? Check out the 2019 tag.

Building

• Depends on cppzmq and friends.

• Requires a built rpi-rgb-led-matrix. Tell CMake where it is with -DRPI_RGB_LED_MATRIX_DIR.

• Build with cmake, e.g.:

  mkdir build
  cd build
  cmake -DRPI_RGB_LED_MATRIX_DIR=/path/to/rpi-rgb-led-matrix ..
  make

Usage

Running the Server

See led-matrix-zmq-server --help for available options. These mostly passthrough to the rpi-rgb-led-matrix library.

sudo ./led-matrix-zmq-server \
  --cols 64 \
  --rows 64 \
  --chain-length 2 \
  --max-brightness 50 \
  # ...etc

Sending Frames

The server is a simple ZMQ REQ-REP loop. All you need to do is send your frame as a big ol' byte chunk then wait for an empty message back. Each frame should be in a RGBA32 format.

Just Pipe It

led-matrix-zmq-pipe is both a bit of an example and a handy tool. It reads raw RGBA32 frames from stdin and sends them to the server.

# Use ffmpeg to convert a video to raw data.
ffmpeg -re -i input.mp4 -vf scale=128:64 -f rawvideo -pix_fmt rgba - \
  | sudo ./led-matrix-zmq-pipe -w 128 -h 64

# Use imagemagick to resize and convert an image to raw data.
convert input.png -resize 128x64^ rgba:- \
  | sudo ./led-matrix-zmq-pipe -w 128 -h 64

# Play a YouTube video.
yt-dlp -f "bv*[height<=480]" "https://www.youtube.com/watch?v=GFq6wH5JR2A" -o - \
  | ffmpeg -re -i pipe: -vf scale=128:64 -f rawvideo -pix_fmt rgba - \
  | sudo ./led-matrix-zmq-pipe -w 128 -h 64

Control Messages

Brightness and color temperature can be controlled through another simple REQ-REP loop.

See led-matrix-zmq-control --help for available options, or see the source to dig deeper.

License

GNU GPL v3. See LICENSE.