The SD interface to the audio extractor consists of data streams, mode and status signals from the SMPTE UHD-SDI RX Subsystem. The audio interface is a 32-bit AXI4-Stream master bus. The following figure shows the top level block diagram of the SDI audio extractor in 32 channel configuration.
In SD-SDI mode, as per SMPTE ST 272, up to 16 channels of audio are extracted from data stream 1 (Y Video In). In HD-SDI mode, as per SMPTE ST 299-1, up to 16 channels of audio are extracted from data stream 1 and 2. In 3G-SDI, 6G-SDI and 12G-SDI modes, as per SMPTE ST 299-1 and SMPTE ST 299-2, up to 32 channels of audio are extracted from data streams 1, 2, 3, and 4. Audio control packets are extracted from data stream 1 and 3 (Y Video In) and data packets are extracted from data stream 2 and 4 (CBCR Video In).
The AMD AXI4-Stream audio interface carries audio samples in Audio Engineering Society (AES3) format. The data width over the AXI4-Stream audio interface is fixed at 32 bits to carry one AES3 sub-frame as shown in the following figure.
The TID indicates the channel number of the audio sample data.
The following figure shows the interface timing diagram for the audio extractor core.