rpi_video

This project implements H264 video record on Raspberry Pi. It wraps a Rust H264 video record library rpi-video-rs which has already implemented the low level features. By taking advantage of Erlang Port, the simple Elixir GenServer APIs are provided.

Since it is an experimental project, not the full video record features of Raspberry Pi are supposed to be implemented. If you have any ideas or need some helps, feel free to send an email to [email protected].

Usage

Add the following to your mix.exs:

defp deps do
  [
    {:rpi_video, "0.0.1"}
  ]
end

Get the dependencies and compile (if something went wrong, please reference the below Development part for details):

mix deps.get
mix compile
mix compile.cargo

Run on a iex console:

iex -S mix
iex(1)> RpiVideo.start(true)    # true for MockServer, and false for RealServer.
iex(2)> RpiVideo.record(true)   # same as above
iex(3)> RpiVideo.stop(true)     # same as above

Development

This project provides two Elixir GenServer implementations MockServer and RealServer.

The MockServer is used for debugging, and compiled only for Apple Mac ({:unix, :darwin}). It simulates the asynchronous process of video record, but no video is captured and saved.

The RealServer could only be compiled and run on a Raspberry Pi. It could capture and save videos from a camera.

The Rust implementations of MockServer and RealServer are compiled by the below command which could identify the current target platform (Mac or Raspberry Pi). Reference the source code in lib/mix/tasks/compile.cargo.ex for details.

max compile.cargo

Since this project requires the real camera to record H264 videos finally, you needs a RPI to run or test. But you could also uses a cross-compiling environment for compiling and developing. Reference the docker folder of project rpi-video-rs which is a separate cross-compiling environment.

For developing on either a RPI device or a Docker container, you should install the standard Rust development environment, and then adds Rust targets as below.

rustup target add arm-unknown-linux-gnueabihf
rustup target add armv7-unknown-linux-gnueabihf

Reference below for how to enable a camera on Raspberry Pi.

Installing Camera Device on RPI

1. Adds text bcm2835-v4l2 to the bottom of file /etc/modules.

sudo echo bcm2835-v4l2 >> /etc/modules

2. Activates the camera in configuration.

sudo raspi-config

3. Follows the prompt to reboot Raspberry PI.

4. You could use the command raspivid to test recording a H264 video and check if the camera is installed properly.

raspivid -o test_video.h264