H.265 / HEVC Video Encoder

Article
08/19/2021

The Media Foundation H.265 video encoder is a Media Foundation Transform that supports encoding content into the H.265/HEVC format. The encoder supports the following profiles:

Main Profile

The H.265 video encoder exposes the following interfaces:

Input Types

The input media type must have one of the following subtypes:

MFVideoFormat_IYUV
MFVideoFormat_NV12
MFVideoFormat_YUY2
MFVideoFormat_YV12

For more information about these subtypes, see Video Subtype GUIDs.

The output type must be set before the input type. Until the output type is set, the encoder's IMFTransform::SetInputType method returns MF_E_TRANSFORM_TYPE_NOT_SET.

Output Types

The encoder supports a single output subtype:

MFVideoFormat_H265

Set the following attributes on the output media type.

Attribute	Description
MF_MT_MAJOR_TYPE	Major type. Must be MFMediaType_Video.
MF_MT_SUBTYPE	Video subtype. Must be MFVideoFormat_HEVC.
MF_MT_AVG_BITRATE	Average encoded bit rate, in bits per second. Must be greater than zero.
MF_MT_FRAME_RATE	Frame rate.
MF_MT_FRAME_SIZE	Frame size.
MF_MT_INTERLACE_MODE	Interlace mode.
MF_MT_VIDEO_PROFILE	H.265 encoding profile. The supported values are: eAVEncH265VProfile_Main_420_8
MF_MT_MPEG2_LEVEL	Specifies the level of the coded video. For more information about profile and level constraints, refer to Annex A of ITU-T H.265.
MF_MT_PIXEL_ASPECT_RATIO	Optional. Specifies the pixel aspect ratio. The default value is 1:1.

After the output type is set, the video encoder updates the type by adding the MF_MT_MPEG_SEQUENCE_HEADER attribute. This attribute contains the sequence header.

Supported IMFTransform methods

The following methods of the IMFTransform interface are supported for the H.265/HEVC encoder:

All other IMFTransform methods will return the error E_NOTIMPL.

Supported ICodecAPI methods

The following methods of the ICodecAPI interface are supported for the H.265/HEVC encoder:

All other ICodecAPI methods will return the error E_NOTIMPL.

Codec Properties

The H.265 encoder implements the ICodecAPI interface for setting encoding parameters. It supports the following properties.

For the codec requirements for HCK encoder certification, see the Certified Hardware Encoder section below.

Property	Description
CODECAPI_AVEncCommonRateControlMode	Sets the rate control mode. The supported modes are: eAVEncCommonRateControlMode_CBR eAVEncCommonRateControlMode_Quality If other modes are specified, the eAVEncCommonRateControlMode_CBR rate control will be used. This is a VT_UI4 value.
CODECAPI_AVEncCommonMeanBitRate	Sets the average bit rate for the encoded bit stream, in bits per second. The valid range is [1 ... 2³²–1]. This is a VT_UI4 value.
CODECAPI_AVEncCommonBufferSize	Sets the buffer size, in bytes, for constant bit rate (CBR) encoding. The valid range is [1 ... 2³²–1]. This is a VT_UI4 value.
CODECAPI_AVEncCommonMaxBitRate	Sets the maximum bitrate for rate control modes that allow a peak bitrate. The valid range is [1 ... 2³²–1]. This is a VT_UI4 value.
CODECAPI_AVEncMPVGOPSize	Sets the number of pictures from one GOP header to the next, including the leading anchor but not the following one. The valid range is [0 ... 2³²–1]. If zero, the encoder selects the GOP size. The default value is zero. This is a VT_UI4 value.
CODECAPI_AVLowLatencyMode	Enables or disables low-latency mode. This is a VT_BOOL value.
CODECAPI_AVEncCommonQualityVsSpeed	Sets the quality/speed tradeoff. This value affects how the encoder performs various encoding operations, such as motion compensation. At higher complexity levels, the encoder runs more slowly but produces better quality at the same bit rate. The valid range is 0 – 100. Internally, this value is mapped to a smaller set of quality/speed levels supported by the encoder. This is a VT_UI4 value.
CODECAPI_AVEncVideoForceKeyFrame	Forces the encoder to code the next frame as a key frame. This is a VT_UI4 value.
CODECAPI_AVEncVideoEncodeQP	When this property is set it will cause the encoder to use the specified QP to encode the next frame and all subsequent frames until a new QP is specified. Valid range: 0–51, inclusive
CODECAPI_AVEncVideoMinQP	This property will set a limit on the minimum QP that the encoder can use during CBR ratecontrol. This is a VT_UI4 value.
CODECAPI_AVEncVideoMaxQP	This property will set a limit on the maximum QP that the encoder can use during CBR ratecontrol. This is a VT_UI4 value.
CODECAPI_VideoEncoderDisplayContentType	Sets whether the content is full-screen video, as opposed to screen content that might have a smaller window of video or have no video at all. This is a VT_UI4 value.
CODECAPI_AVEncNumWorkerThreads	Sets the number of threads used to perform the compression operation. The encoder will divide the frame into tiles such that the number of threads equals the number of tiles. The number of logical processors. The number of threads must be less than or equal to the number of logical processors. The size of the frame. The size of a tile must bigger than or equal to 265x64 pixels. Parity. The number of threads must be an even value. If the specified value is odd then the next lower even value will be used. This is a VT_UI4 value.

Certified Hardware Encoder

If a certified hardware encoder is present, it will generally be used instead of the inbox system encoder for Media Foundation related scenarios. Certified encoders are required to support a certain set of ICodecAPI properties and can optionally support another set of properties. The certification process should guarantee that the required properties are properly supported and, if an optional property is supported, that it is also properly supported.

The following is the set of required and optional ICodecAPI properties for encoders to pass the HCK encoder certification.

Requirements

Requirement	Value
Minimum supported client	Windows 10 [desktop apps only]
Minimum supported server	None supported
DLL	Mfh265enc.dll