Windows Media Video 9 Screen Encoder
The Windows Media Video 9 Screen encoder is optimized for encoding sequential screen shots from computer monitors.
The class identifier (CLSID) for the Windows Media Video 9 Screen encoder is represented by the constant CLSID_CMSSCEncMediaObject2. You can create an instance of the encoder by calling CoCreateInstance.
The following input types are supported by the Version 9 Screen encoder when it is being used as a DirectX Media Object (DMO).
The following input types are supported by the Version 9 Screen encoder when it is being used as a Media Foundation Transform (MFT).
The four-character code (FOURCC) for Windows Media Video Screen Version 9 encoded content is "MSS2".
The following output types are supported by the Version 9 Screen encoder.
The Windows Media Video 9 Screen encoder supports the following properties.
Specifies the overhead, in bytes per packet, required for the container that is used to store the compressed content.
Specifies the buffer window, in milliseconds, of a constrained variable-bit-rate (VBR) stream at its average bit rate (specified by MFPKEY_RAVG).
Specifies the buffer window, in milliseconds, of a constrained variable-bit-rate (VBR) stream at its peak bit rate (specified by MFPKEY_RMAX).
Specifies whether the encoded video bit stream contains a buffer fullness value with every key frame.
Specifies the number of video frames encoded by the codec.
Specifies the number of video frames encoded by the codec that actually contain data.
This property is superseded by MFPKEY_COMPLEXITYEX.
Specifies the complexity of the encoder algorithm.
Specifies a numeric representation of the tradeoff between motion smoothness and image quality in codec output.
Specifies the number of video frames dropped during encoding.
Specifies the end of an encoding pass.
Specifies the FOURCC that identifies the encoder you want to use.
Specifies the maximum time, in milliseconds, between key frames in the codec output.
Specifies the maximum number of passes supported by the codec.
Windows XP and later. Read/write.
Specifies the number of passes that the codec will use to encode the content.
Specifies QP. Possible values are 1.0 through 31.0.
Specifies the average bit rate, in bits per second, used for 2-pass variable-bit-rate (VBR) encoding.
Specifies the peak bit rate, in bits per second, used for constrained 2-pass variable-bit-rate (VBR) encoding.
Specifies the number of video frames passed to the encoder during the encoding process.
Specifies whether the codec will use variable-bit-rate (VBR) encoding.
Specifies the actual quality level for quality based (1-pass) variable-bit-rate (VBR) encoding.
The amount of content, in milliseconds, that can fit into the model buffer.
Specifies the number of video frames that were skipped because they were duplicates of previous frames.
A screen encoder object exposes the IMediaObject interface so that the object can be used as a DirectX Media Object (DMO), and it exposes the IMFTransform interface so that the object can be used as a Media Foundation Transform (MFT).
A screen encoder behaves as a DMO or an MFT depending on which interfaces you obtain and which version of Windows is running. The following table shows the conditions under which a screen encoder behaves as a DMO or an MFT.
|Operating system||Encoder behavior|
|Windows XP||A Windows Media Screen encoder always behaves as a DMO.|
|Windows Vista and Windows 7||By default, a Windows Media Screen encoder behaves as a DMO. If you obtain an IMFTransform interface on a screen encoder, it behaves as an MFT.|
|Windows XP, Windows Vista, or Windows 7|
- Codec Objects
- Codec Implementation
- Using the Windows Media Video 9 Screen Codec
- Windows Media Video 9 Screen Decoder