Zynq Ult VCU TRD User Guide
25
UG1250 (v2019.1) May 29, 2019
Chapter 3:
APU Software Platform
A pad is a connection endpoint through which an entity can interact with other entities.
Data produced by an entity flows from the entity's output to one or more entity inputs. A
link is a point-to-point oriented connection between two pads, either on the same entity or
on different entities. Data flows from a source pad to a sink pad.
An entity is a basic media hardware building block. It can correspond to a large variety of
blocks such as physical hardware devices (e.g., image sensors), logical hardware devices
(e.g., soft IP cores inside the PL), DMA channels, or physical connectors. Physical or logical
devices are modeled as subdevice nodes and DMA channels as video nodes.
A media device node is created that allows the user space application to configure the
video pipeline and its subdevices through the libmediactl and libv4l2subdev libraries. The
media controller API provides this functionality:
• Enumerates entities, pads, and links
• Configures pads
°
Sets media bus format
°
Sets dimensions (width/height)
• Configures links
°
Enable/disable
°
Validates formats
shows the media graph for the SDI-RX, TPG, HDMI RX, and CSI RX video capture
pipelines as generated by the media-ctl utility. The TPG subdevice is shown in white with its
corresponding control interface address and subdevice node in the center. The numbers on
the edges are pads and the solid arrows represent active links. The grey boxes are video
nodes that correspond to Frame Buffer Write channels, in this case write channels (outputs).
