The Decoder block is capable of decompressing HEVC (ISO/IEC 23008-2 High Efficiency Video Coding) and AVC (ISO/IEC 14496-10 Advanced Video Coding) compliant streams. It provides complete support for these standards, including support for 8-bit and 10-bit color depth, Y-only (monochrome), 4:2:0 and 4:2:2 chroma formats, up to four simultaneous instances of 4K UHD at 60 Hz performance. It also contains global registers, an interrupt controller, and a timer.
A microcontroller (MCU) subsystem controls each VDU decoder instance. The APU uses a 32-bit AXI4-Lite slave interface to control the MCU. Two 128-bit AXI4 master interfaces are used to move video data and metadata to and from the system memory. A 32-bit AXI4 master interface is used to fetch the MCU software (instruction cache interface) and load/store additional MCU data (data cache interface). VDU applications running on the APU use the VDU Control Software library API to interact with the decoder microcontroller. You cannot modify the microcontroller firmware.
The decoder includes control registers, a bridge unit, and a set of internal memories. The bridge unit manages the request arbitration, burst addresses, and burst lengths for all external memory accesses that the decoder requires.