Input Formats, Input Settings, and Data Unit Extensions
[The feature associated with this page, Windows Media Format 11 SDK, is a legacy feature. It has been superseded by Source Reader and Sink Writer. Source Reader and Sink Writer have been optimized for Windows 10 and Windows 11. Microsoft strongly recommends that new code use Source Reader and Sink Writer instead of Windows Media Format 11 SDK, when possible. Microsoft suggests that existing code that uses the legacy APIs be rewritten to use the new APIs if possible.]
The writer object supports input settings, input formats, and data unit extensions, all of which enable you to control features of the writer. It is not always obvious which methods to use to control a specific feature.
Input formats are media formats that describe the basic properties of the media that you pass to the writer for encoding. For example, the frame size and color space of input video is described by the input format.
Input settings are characteristics of the input data beyond the basics, or information about transforms to perform on the data. Interlaced video settings and information about a watermarking system are examples of input settings.
Data unit extensions, also called payload extension systems, are values that are attached to individual samples in the data section of the file. SMPTE time codes and non-square pixel information are examples of data unit extensions.
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