编写插件

You are now ready to learn how to build a plugin. In this part of the guide, you will learn how to apply basic GStreamer programming concepts to write a simple plugin. The previous parts of the guide have contained no explicit example code, perhaps making things a bit abstract and difficult to understand. In contrast, this section will present both applications and code by following the development of an example audio filter plugin called “MyFilter”.
现在你已经准备好学习如何创建插件了。在本部分指南中，你将学习如何应用基本的 GStreamer 编程概念来编写一个简单的插件。本指南的前几部分没有明确的示例代码，可能会让人觉得有些抽象，难以理解。相比之下，本节将通过开发一个名为 "MyFilter "的音频过滤器插件示例，介绍应用和代码。

The example filter element will begin with a single input pad and a single output pad. The filter will, at first, simply pass media and event data from its sink pad to its source pad without modification. But by the end of this part of the guide, you will learn to add some more interesting functionality, including properties and signal handlers. And after reading the next part of the guide, Advanced Filter Concepts, you will be able to add even more functionality to your plugins.
示例滤波器元件一开始只有一个输入pad和一个输出pad。起初，滤波器只是简单地将媒体和事件数据从其 sink pad 传递到源 pad，而不做任何修改。但在本部分指南的最后，你将学会添加一些更有趣的功能，包括属性和信号处理器。阅读本指南的下一部分 "高级过滤器概念 "后，您将能为插件添加更多功能。

### Subpages: 子页面：

Constructing the Boilerplate 构建模板

Specifying the pads 指定pad

The chain function 链功能

The event function 事件功能

The query function 查询功能

What are states? 什么是状态？

Adding Properties 添加属性

Signals 信号

Building a Test Application 构建测试应用程序