User guide

10–4 Chapter 10: Clocked Video Input MegaCore Function
Functional Description
Video and Image Processing Suite January 2013 Altera Corporation
User Guide
2. Read Status register bit 0. When this is a 1, the MegaCore function outputs data.
This occurs on the next start of frame or field that matches the setting of the Field
order in the parameter editor.
The sequence for stopping the output of the MegaCore function is as follows:
1. Write a 0 to
Control register bit 0.
2. Read
Status register bit 0. When this is a 0, the MegaCore function has stopped
data output. This occurs on the next end of frame or field that matches the setting
of the Field order in the parameter editor.
The starting and stopping of the MegaCore function is synchronized to a frame or
field boundary.
Table 10–3 lists the output of the MegaCore function with the different Field order
settings.
Format Detection
The Clocked Video Input MegaCore function detects the format of the incoming
clocked video and uses it to create the Avalon-ST Video control packet. It also
provides this information in a set of registers.
The MegaCore function can detect the following different aspects of the incoming
video stream:
■ Picture width (in samples)—The MegaCore function counts the total number of
samples per line, and the number of samples in the active picture period. One full
line of video is required before the MegaCore function can determine the width.
■ Picture height (in lines)—The MegaCore function counts the total number of lines
per frame or field, and the number of lines in the active picture period. One full
frame or field of video is required before the MegaCore function can determine the
height.
■ Interlaced/Progressive—The MegaCore function detects whether the incoming
video is interlaced or progressive. If it is interlaced, separate height values are
stored for both fields. One full frame or field of video and a number of lines from a
second frame or field are required before the MegaCore function can determine
whether the source is interlaced or progressive.
■ Standard—The MegaCore function provides the contents of the vid_std bus via
the
Standard register. When connected to the rx_std signal of a SDI MegaCore
function, for example, these values can be used to report the standard (SD, HD, or
3G) of the incoming video.
Table 10–3. Synchronization Settings
Video Format Field Order Output
Interlaced F1 first Start, F1, F0, ..., F1, F0, Stop
Interlaced F0 first Start, F0, F1, ..., F0, F1, Stop
Interlaced Any field first Start, F0 or F1, ... F0 or F1, Stop
Progressive F1 first No output
Progressive F0 first Start, F0, F0, ..., F0, F0, Stop
Progressive Any field first Start, F0, F0, ..., F0, F0, Stop