What does an AV receiver do?

Question

Can someone please explain what the purpose of it is?

Answer 1

To take input from multiple sources (DVD, radio, VCR etc.) and output the sound to speakers.

Answer 2

A/V receivers do audio and video switching, decode audio programming (DTS, Dolby, etc.), and provide amplification to drive the speakers.

Answer 3

It's main purpose is to take weak audio signals (called "line level") and amplify the signals to drive speakers and give you volume control.

But they have become small computers because they need to accept Mono signals, stereo analog signals, Dolby Digital (in optical or coaxial form) or HDMI signals and decode them.

The receiver also does video switching, bass management, speaker calibrations, AM/FM tuning, etc.