hello-world-gstreamer

This is a proof of concept for a GStreamer app using Python.

Motivation

• Learn how to use GStreamer with Python, not only with C++ as I’ve been doing
• Create a silly animated GIF for my website 🙂

What it does

• The app takes two video sources — your webcam and a test video — and merges them into a single video using compositor
• The compositor output is then split into two branches using a tee. The first branch shows a live preview using autovideosink
• The second branch turns the video into a GIF using the gifenc element from the gst-plugins-rs project, saving the GIF to a timestamped file.
• Every GIF_DURATION_SECONDS=5, the app stops writing to the current GIF through valve[drop=True], starts a new timestamped file, and keeps the preview branch (autovideosink) uninterrupted — a manual rotation that’s necessary because splitmuxsink doesn’t work with gifenc 🙁

Quick start

Install dependencies

Tested on Ubuntu 24.04.3 LTS.

sudo apt install python3-gi python3-pytest python3-freezegun gir1.2-gstreamer-1.0 gstreamer1.0-tools gstreamer1.0-plugins-good gstreamer1.0-plugins-bad libssl-dev libglib2.0-dev pkg-config build-essential libgstreamer1.0-dev libgstreamer-plugins-base1.0-dev

Install Rust and cargo-c

Required to compile gifenc.

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh -s -- -y
cargo install cargo-c

Build gifenc from gst-plugins-rs

export GST_RS_VERSION=gstreamer-1.27.2

git clone --branch $GST_RS_VERSION --depth 1 \
    https://gitlab.freedesktop.org/gstreamer/gst-plugins-rs.git ./gst-plugins-rs
cd ./gst-plugins-rs
cargo cbuild -p gst-plugin-gif

Install globally:

cargo cinstall -p gst-plugin-cdg --prefix=/usr

Or just make gifenc available for the current session:

export GST_PLUGIN_PATH="path-of-gst-plugins-rs/target/x86_64-unknown-linux-gnu/release:$GST_PLUGIN_PATH"

Test the element:

gst-inspect-1.0 gifenc

Run the application

python src/main.py

Stop the recording

Ctrl+C in the terminal window

Test the application

pip3 install --break-system-packages pytest==8.4.2 freezegun==1.5.5
pytest .