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Configuring Codec MFTs

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This topic describes the process of configuring the codec MFTs. Each codec has specific procedures, but the information common to all is described here.

Configuring MFT Inputs and Outputs

Every MFT supports specific input and output types. You can retrieve supported input types by repeatedly calling IMFTransform::GetInputAvailableType, incrementing the type index with each call. When you find an appropriate type, set the input type by calling IMFTransform::SetInputType. You can then repeat the process for the output type using the calls IMFTransform::GetOutputAvailableType and IMFTransform::SetOutputType. You must query or set the available output types only after setting the input type.

Configuring the Codec MFTs for Encoding

All of the Windows Media Audio and Video codecs support a variety of encoding features. These features are generally configured by setting properties on the MFT by using the methods of the IPropertyStore interface. Some properties are configured by the methods of the codec interfaces described in Interfaces.

The general order of operations for configuring an encoding MFT is as follows:

  1. Configure codec features as desired by using the methods of IPropertyStore.
  2. Use the codec MFT interfaces to configure additional features, if needed.
  3. Configure the input and output types. The order in which the types should be configured varies for individual codecs. For more information, see Working with Audio and Working with Video.

Configuring the Codec MFTs for Decoding

Decoding is simpler than encoding, as fewer decoder features are supported.

The general order of operations for configuring a decoding MFT is as follows:

  1. Configure decoder features as desired by using the methods of IPropertyStore.
  2. Set the input type to the type used for the encoder output.
  3. Configure the output type. The supported output types are different for different inputs.

Note   It is important to use the same media type for the decoder input as was used for the encoder output. This is because the Windows Media Audio and Video codecs use media formats with extra data. Without the extended format data, you cannot decode the compressed content.

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