# Input/Output Operations

In the Filter .NET API, input and output can be either a physical file accessed through a file path, or a .NET stream. Depending on the method signature you use, you can create the following filtering processes:

- filter an input file to output file
- filter an input file to an output stream
- filter an input stream to an output stream
- filter an input stream to an output file
- filter an input file and return one chunk of data at a time
- filter an input stream and return one chunk of data at a time

Many methods in the .NET API have method signatures supporting one or more of these filtering processes. When you select a method, make sure that you use the correct signature for the desired input and output type.

The input source can be set by calling the `SetInputSource` method, or prior to using the `DoFilter`, `CanFilter`, `CanFilterEx`, `GetDocFormatInfo`, or `GetSummaryInfo` methods. The latter methods take the input source as one of their parameters.

NOTE: When the input source is from a .NET stream, Filter creates an internal buffer from the stream. If the input is a large file, Micro Focus recommends that you use a file as the input source.

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