A filter graph is used in multimedia processing. For example to capture video from a webcam. Filters take input, process it or change the input, and then output the process data. An example of a filter, would be a video codec that takes raw uncompressed video and compresses it using a video standard such as H.264. To compress a multimedia stream a filter graph could have two inputs:
- Audio
- Video
Usually these are expressed as file sources. The file sources would feed compression filters, the output of the compression filters would be feed to a multiplexer that would combine the two inputs and produce a single output. An example of a multiplexer would be an MPEG transport stream creator. Finally the multiplexer output would be fed to a file sink, which would create a file from the output.
A filter graph in multimedia processing is a directed graph. Edges represent one way data flow and nodes represent a data processing step. The term pins or pads are used to describe the connection point between nodes and edges.
Example of programs that use filter graphs
- GStreamer - Linux based multimedia framework. In Gstreamer a filter is called an element. Filter graphs can be built with the GStreamer Editor.
- GraphEdit - Microsoft tool for building filter graphs
- DirectShow - Windows based multimedia framework.
- GraphEditPlus - another tool for building DirectShow filter graphs and generating C++ source code for them.
See also
Explanation of filter graph in DirectShow article: DirectShow#Architecture
External links
DirectShow
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