Fastvideo

A lightweight, zero-copy video pipeline framework for embedded Linux.

Fastvideo is a C library (libfastvideo.so) and a small set of command-line applications for building real-time video streams from cameras, ISPs, GPUs, displays and network outputs. It is designed for small boards such as the Raspberry Pi, where every copy of a frame through user space costs precious CPU time.

Why Fastvideo?

• Zero copy wherever possible – frames travel from one device to the next as DMA buffers (dma_fd), so the CPU never has to touch the pixels.
• Modular by design – every stage of a stream (camera, ISP, GPU, screen, encoder, network, file…) is a plugin. A stream is simply a chain of plugins described on the command line.
• Declarative configuration – hardware is described once in a JSON file; the command line only picks which devices to connect.
• GPU processing – apply GLSL shaders (including ShaderToy filters) to live video with OpenGL ES, on X11, Wayland, DRM/KMS or off-screen.
• Live control – camera and ISP settings can be changed while streaming, through a UNIX socket, which makes Fastvideo easy to drive from a web server.

How it works

A stream is built from sources (-i), optional transfers (-t) and sinks (-o), each named after an entry in the JSON configuration file:

  -i cam-imx477      -o isp-in        -i isp-out        -o gpu
 ┌─────────────┐   ┌──────────┐     ┌───────────┐     ┌──────────┐
 │   camera    │──▶│ ISP in   │ ... │  ISP out  │────▶│   GPU    │──▶ screen
 └─────────────┘   └──────────┘     └───────────┘     └──────────┘
          dma_fd buffers, no copy through user space

The project provides three applications:

Application	Purpose
fastvideo	Creates and runs the streams described by a JSON file.
fastconfig	Generates a JSON file listing all the hardware found on the host.
fastsetting	Opens a UNIX socket that receives JSON objects to control the devices.

Image-quality algorithms (AWB, AEC, AF) are hardware-specific, so they run in a separate server: Fastvideo extracts statistics from the V4L2 metadata capture device and pushes them to that server through a named pipe. These servers live in the utils/ directory.

Quick start

On a Debian-like system with a USB webcam:

$ sudo apt install libjansson-dev wayland-protocols libdrm-dev libgbm-dev \
                   libgles2-mesa-dev libegl1-mesa-dev
$ make defconfig
$ make
$ sudo make install
$ fastvideo -j /etc/fastvideo/uvc_desktop.json -i uvc -o gpu

The webcam image should appear in a window rendered by the GPU.

Documentation

Guide	Contents
Building and installing	Dependencies, native and cross compilation, installation paths.
Applications	Command-line reference for fastvideo, fastconfig and fastsetting.
Modules	Feature matrix and JSON reference for every module (v4l2, gpu, screen, …).
Examples on a PC	Webcam, ShaderToy filters, software trigger, performance checks.
Raspberry Pi	Camera modules on Raspberry Pi 3, 4 and 5, 3A algorithms.
RP1 front-end configuration	CSV format of the Pi 5 front-end configuration and the csv2pisp_fe_config tool.
Object detection with Hailo and YOLOv8	The hailo module, nmsclient and the rectangles.glsl overlay.
Writing a convert library	Adding your own CPU pixel converters.
Contributing and roadmap	Writing a new module and the features still missing.

Licence

Fastvideo is released under the MIT Licence.