Start of Frame Signals - m_axis_video_tuser, s_axis_video_tuser - 2.4 English

Video Processing Subsystem Product Guide (PG231)

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2.4 English

The Start-Of-Frame (SOF) signal, physically transmitted over the AXI4-Stream TUSER signal, marks the first pixel of first incoming video field at slave/input side and first pixel of every outgoing video frame at the master/output side. Every incoming interlaced Video Frame represented by two video fields, which are odd line and even line video field. The SOF pulse is 1 valid transaction wide, and must coincide with the first pixel of the frame. Refer to the following figure.

SOF serves as a frame synchronization signal, which allows downstream cores to reinitialize, and detect the first pixel of a frame/first field. The SOF signal can be asserted an arbitrary number of ACLK cycles before the first pixel value is presented on TDATA, as long as a TVALID is not asserted.

Figure 1. Example of SOF Handshake, Start of a New Frame