A home theater requires a surround processor AVP)… which takes input signals from different sources like BluRay, Cable box, Amazon Cube, Apple TV and splits them into different channels (basically a multichannel preamp and decoder). This signal is then fed into a multichannel amp. There are also AVP that contain seven or more channel amplifiers. Most folks (non-fanatic) use these. They do not sound as good as audio only components, but since video distracts you the sound quality is not as critical.
i have separate AV and audio systems (preferred). My home theater has a surround processor and a separate five channel amp. You can see my systems under my user ID in virtual systems.