Which device converts an AES signal and an SDI or HD-SDI signal into a single ASI bit stream?

The correct choice is an encoder. An encoder is designed to take a variety of input signals, including AES (Audio Engineering Society) signals as well as SDI (Serial Digital Interface) or HD-SDI, and convert these into a single ASI (Asynchronous Serial Interface) bitstream. This process involves the necessary encoding to ensure that both audio and video signals are efficiently combined and transmitted as a single digital signal, which is critical for ensuring compatibility and reducing the complexity of signal management in broadcasting environments.

In broadcasting and digital video, the conversion process is essential for integrating different types of content, which promotes streamlined workflows and is necessary for the delivery of television signals. This capability to unify multiple inputs into one output is a fundamental function of encoders in video broadcasting systems.