Question: What is the primary purpose of the streaming-server extensions defined for 3GP files in the context of telecommunications?
Option 1: To enhance User Equipment (UE) battery life during video playback
Option 2: To facilitate end-to-end encryption for all media types
Option 3: To enable servers to select, combine, and switch between tracks with alternative encodings for adaptive streaming
Option 4: To introduce a new protocol for signaling between the server and UE
Explanation: The correct answer is Option 3 because the streaming-server extensions are specifically designed to allow servers to manage different tracks efficiently. This includes generating descriptions with alternatives, selecting and combining tracks before presentation, switching between tracks during a session, and determining decoding order and playout timestamps. These functionalities are crucial for adaptive streaming, which adjusts the quality of the stream based on the user's internet connection, thereby enhancing the viewing experience.