Setting Data Unit Extensions
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Some streams are configured to use data unit extensions to associate supplementary data with individual samples. For more information about extended samples, see Data Unit Extensions.
Most data unit extension systems require an extension on every sample in the stream. If you do not provide an extension of the correct size, the writer will reject the sample.
To add extended data to a sample, use the INSSBuffer3::SetProperty method. You can get information about the data unit extensions configured on a stream by using the IWMStreamConfig2::GetDataUnitExtensionCount and IWMStreamConfig2::GetDataUnitExtension methods.
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