Altera Video and Image Processing Suite User Manual

Page 272

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Table A-1: Class Description

The table describes each of the classes in the av_st_video_classes package.
Note: The classes listed do not contain information about the physical transport mechanism and the Avalon-ST

Video protocol. To foster advanced verification techniques, Altera uses a high-level abstract view.

Class

Description

class c_av_st_video_item

The most fundamental of all the classes.
Represents any item that is sent over the Avalon-ST bus and

contains a

packet_type

field.

You can set the field to

video_packet

,

control_packet

, or

user_

packet

types. These three packet types are represented by classes

which extend this base class.
Structuring the classes in this way allows you to define the

mailboxes and queues of c_av_st_video_item. Then, you can send

any type of packet in the order that they appear on the bus.

class c_pixel

Fundamental and parameterized class.
Comprises of an array of channels that contains pixel data. For

example, a pixel from an RGB24 video system comprises an array

of three channels (8 bits per channel).
A pixel for a YcbCr system comprises two channels. An individual

channel either represents a luminance or chroma-type component

of video data, one RGB component, or one alpha component. The

class provides “getters”, “setters”, and “copy” methods.
The parameters for this class are BITS_PER_CHANNEL and

CHANNELS_PER_PIXEL.

class c_av_st_video_data

Parameterized class.
Contains a queue of pixel elements. This class library is used by

other classes to represent fields of video and line (or smaller) units

of video. It extends c_av_video_item. The class provides methods

to push and pop pixels on and off the queue.
The parameters for this class are BITS_PER_CHANNEL and

CHANNELS_PER_PIXEL.

A-4

Avalon-ST Video Class Library

UG-VIPSUITE

2015.05.04

Altera Corporation

Avalon-ST Video Verification IP Suite

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