When the Apple TV was first released in 2007, it was described as an “easy to use and fun way to wirelessly play all your favorite iTunes content from your PC or Mac on your widescreen TV, including movies, TV shows, music, photos and podcasts.” Three years later, the Generation 2 Apple TV was released in a form factor 80% smaller than the original device and with enhanced streaming capabilities.
The Generation 3 Apple TV was released on March 7, 2012, and featured “1080p programming including iTunes movies and TV shows, Netflix, Vimeo, photos and more in HD. With iTunes in the Cloud, customers can purchase and play their favorite movies and TV shows from the iTunes Store and watch them instantly on their HD TV.”
In addition to a “simpler, refined user interface,” AirPlay allowed users to stream or mirror content from an iPad or iPhone 4S to Apple TV.
The Apple TV Generation 3 looked identical to the Generation 2 model. It was 0.9 inch high, 3.9 x 3.9 inches square (with rounded corners) and weighed 0.6 pound. It used an Apple single-core A5 processor and had both Wi-Fi (802.11a, b, g, or n) and a 10/100BASE-T Ethernet port. Its audio/visual ports included HDMI and optical audio, and its maximum video output was 1080p, 1920 x 1080 HD (the Generation 2 was capable only of 720p).
The Early 2013 version of the Generation 3 Apple TV (model A1469) was not officially touted by Apple as an upgrade, but the internal hardware changed in approximately March 2013. EveryMac called this the Generation 3 “Revision A” version and reported that “Compared to the model it quietly replaced, it has a smaller 28 nm version of the Apple A5 processor (S5L8947), different identifiers, and supports Peer-to-Peer AirPlay (running Apple TV Software Update 7.0 or later).”
Sources: Apple (original Apple TV, Generation 2 Apple TV, Generation 3 Apple TV, technical specifications), EveryMac (early 2012, early 2013)