GStreamer Workshop Part 1: Displaying Camera Video in Real Time

This article is a translated version of my original post on Qiita. Original (Japanese): https://qiita.com/segur/items/2585dbf5a51ce7acec3b

Hello! This article is the first in the "GStreamer Workshop" series.

In this first session, we'll display video from a camera connected to your PC.

Installation Steps

Install GStreamer using the following commands.

# For macOS
brew install gstreamer gst-plugins-base gst-plugins-good

# For Windows
choco install gstreamer --package-parameters="'/Full'" -y

After installation is complete, restart your terminal.

You can display camera video in a window in real time with the following commands!

# For macOS
gst-launch-1.0 avfvideosrc ! videoconvert ! queue ! autovideosink

# For Windows
gst-launch-1.0 mfvideosrc ! videoconvert ! queue ! autovideosink

You may be prompted to allow camera access the first time you run the command.
For macOS, go to Settings > Privacy & Security > Camera and allow terminal to use the camera.

In GStreamer, small processing units called elements are connected in a pipeline.

Element	Windows	macOS	Role
`mfvideosrc`	✅	❌	Camera input (source). Uses Windows Media Foundation to capture video from the camera.
`avfvideosrc`	❌	✅	Camera input (source). Uses macOS AVFoundation to capture video from the camera.
`videoconvert`	✅	✅	Video format conversion. Formats output for the next element (e.g., pixel format).
`queue`	✅	✅	Asynchronous buffer. Decouples processing between elements for smooth video display.
`autovideosink`	✅	✅	Video display. Automatically selects the optimal rendering backend for your OS to display video on the screen.

The ! is an operator connecting elements. It means "send the output of this element to the input of the next element."

A ! B ! C

This indicates processing in the order of "A → B → C".

Next time, we'll explain how to use GStreamer to stream camera video in real time over RTSP!

https://qiita.com/segur/items/e88a293cf9dc49ed08ec