DirectShow, as you might have guessed, is a COM based multimedia framework that makes the task of capturing, playing back, and manipulating media streams easier（DirectShow是一个基于组件对象模块（COM）的多媒体框架，可以让捕捉、播放以及操作媒体流变的更容易）. It was formerly known as ActiveMovie, until it became known as DirectShow. DirectShow might internally use DirectSound and DirectDraw when playing a media, provided there is support from the hardware; otherwise, it might use the traditional Wave APIs and GDI APIs（DirectShow在硬件支持的情况下，可能内部会使用DirectSound以及DirectDraw来播放媒体。否则的话，它就可能会使用传统的Wave  APIs和GDI APIs）.

 

Filters: Technically, Filters are just C++ classes complying（遵从） with the COM interface, which take input in some form, process the data, and produce some output in the same/or different form（Filters是遵循COM接口的C++类，以一些方式获取输入，处理数据，并且以同样/或不同的方式产生输出）. A Filter represents each stage in the processing of a media type.

 

Pins: A Pin is an interface in itself, and every Filter must implement at least one Pin（Pin自身是一个接口，并且每个Filter必须实现至少一个Pin）. Pins are a way for Filters to talk to other Filters（Pins是Filters之间互相联系的一种方式）. Typically, a Filter might have an input pin and an output pin（典型地，一个Filter可能有一个输入pin和一个输出pin）. During the processing of the media, a Filter takes input through its input pin, processes the data, and passes the output to another filter through its output pin（在处理媒体时，Filter从输入pin获取输入，处理数据，并且通过输出pin将输出传递给另一个Filter）. The other filter, as is obvious, receives the processed data through its input pin. So, basically, the output pin of one filter is connected with the input pin of another filter, and that is how they talk（所以，本质上，一个Filter的输出pin是与另一个Filter的输入pin相连接的，这就是它们之间互相联系的方式）.

 

Filter Graph and Filter Graph Manager: A Filter Graph is a sequence of connected filters（Filter Graph是一系列相连接的Filters）. The processing of any type of media involves a Filter Graph with a specific set of filters most suitable for that media type（处理任何类型的媒体都涉及到一个Filter Graph，它由一组特定的最适合该媒体类型的Filters组成）. The Filter Graph Manager is the divine power that lets you create these Filter Graphs, add Filters to a Filter Graph, connect the Pins of the appropriate Filters, and finally, run the graph which accomplishes our objective, which is, if you remember, playing the media（Filter Graph Manager允许你创建Filter Graphs，添加Filters到Filter Graph，将合适的Filters的Pins相连接，并且最终运行Graph来播放媒体）.

 

A Source Filter takes the input from a file or a URL or a capture device, and processes the data in a form which can be consumed by other filters（Source Filter从一个文件或URL或捕获设备中获取输入，并且处理生成可供其他Filters使用的数据）. A characteristic of a source filter is that it has no input pins and only one output pin（Source Filter的一个特性是它没有输入pins，只有一个输出pin）. Note: Pins are a secret between filters only. A Renderer Filter takes the input from the previous filter, and renders it to a sound device or a display device or a file, in case of capture（Renderer Filter从先前的Filter获取输入，并且将数据以捕获的方式渲染到一个音频设备，或一个显示设备，或一个文件）. Remember, this might use DirectSound or DirectDraw internally. A characteristic of a renderer filter is that it has one input pin and no output pins（Render Filter的一个特性是它由一个输入pin，却没有输出pins）. Everything in between a source filter and a renderer filter is called a Transform Filter. A transform filter might have one or more input pins and one or more output pins.