Streaming Media Box

Overview

A streaming media box is a small computer whose only job is to fetch video off the network and put it on a TV. The Mainboard holds a media Compute SoC Module with hardware video decoders, RAM and flash; the Port Board sends the picture out over HDMI and brings the network in; a Wi-Fi/Bluetooth Module adds Wi-Fi and Bluetooth; and a Remote Control drives the interface from the couch. Everything sits in a compact Enclosure fed by an external Power Supply.

It looks trivial next to a games console, and it is, on purpose. There is no local rendering to speak of, so there is no battery, no fan and no heatsink stack: the SoC decodes a compressed stream and the box stays cool passively. The engineering is in the decode pipeline, the HDMI/HDCP path, and a network link fast enough for 4K HDR.

How it works

A title arrives as a compressed stream over Wi-Fi through the Wi-Fi/Bluetooth Module or over the wired Ethernet Jack, where the Ethernet PHY bridges the cable to the SoC's network controller. The Compute SoC Module runs the app and OS from the eMMC Storage, buffers frames in the DDR4 Memory memory, and feeds the bitstream to its hardware decoder, which expands it to full video without taxing the CPU.

Decoded frames go to the HDMI Transmitter IC, which serializes video and audio onto the HDMI Port and runs the HDCP handshake so protected content will play. The TV's EDID tells the box which resolutions, refresh rates and HDR formats the panel supports, and the SoC picks the best match. A Power Management IC derives the SoC and memory rails from the DC input.

Control is wireless. The Remote Control pairs over Bluetooth Low Energy through its BLE/IR Radio; its Microcontroller reports key presses from the Remote Button array, and a Voice Microphone streams voice for search. The same BLE/IR Radio keeps an IR emitter so it can also power the TV on and change its volume, which is why setup asks for your TV brand.