First, decide whether to write the filter from scratch or copy and modify a filter that already exists and is similar to what you want to accomplish.

首先，确定是从头开始编写过滤器，还是复制并修改已存在的类似过滤器。

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The basic design is to start with the video4linux source, filter it into RGB, and then send one copy to the screen and one to an image sink that can occasionally save JPEGs.

基本设计思想是，从video4linu x源开始，将其过滤为rgb，然后将它的一个副本发送到屏幕，另一个发送到可以临时保存JPEG文件的图像接收器。

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If you do have a filter that requires input from stdin, you might think of using the cat command to copy the file to stdout, which would work.

如果您有要求来自 stdin 的输出的过滤器，那么可以考虑使用 cat 命令将文件复制到 stdout。

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