User guide

Appendix A: Avalon-ST Video Verification IP Suite A–17
Video File Reader Test
January 2013 Altera Corporation Video and Image Processing Suite
User Guide
In Stage 3, the video source BFM retrieves the data from its mailbox, recasts the data
back into a
c_av_st_video_data video object, and begins translating it into
transactions for the Avalon-ST source BFM. To indicate that a video packet is being
sent, there is one transaction per pixel and an initial transaction with LSBs of 0×0
when using RGB24 data, 24-bit data buses, and parallel transmission.
In Stage 4, the Avalon-ST source BFM turns each transaction into beats of data on the
Avalon-ST bus, which are received by the DUT.
In Stage 5, the DUT processes the data and presents the output data on the Avalon-ST
bus. The Avalon-ST Sink BFM receives these and triggers a
signal_transaction_received event for each beat.
In Stage 6, after the video sink BFM detects the
signal_transaction_received event,
the video sink BFM starts collecting transaction data from the BFM. When a start of
packet (SOP) beat is detected, the type of the packet is verified, and transaction data is
pushed into a pixel object, which is in turn pushed into a video_data object.
In Stage 7, an end of packet (EOP) is seen in the incoming transactions, the video sink
BFM casts the video data into a
c_av_st_video_item object, and transfers the data
into its mailbox. The file writer then receives the video item.
Lastly, in Stage 8, the file writer recasts the video item to a video data packet, pops off
the pixel, and writes the data to the output file as binary data.