The filter will then inspect the request object and decide to forward the request to the next component in the chain, or stop the request and send a response directly back to the client.

The basic design is to start with the video4linux source, filter it into RGB, and then send one copy to the screen and one to an image sink that can occasionally save JPEGs.

It specifies an interface for a consumer to subscribe, filter notifications, and manage subscriptions and an interface for publishers to send notifications.