CODECAPI_AVEncVideoEncodeFrameTypeQP property

Specifies the frame types (I, P, or B) that the quantization parameter (QP) is applied to.

Data type

ULONGULONG (VT_UI8)

Property GUID

CODECAPI_AVEncVideoEncodeFrameTypeQP

Remarks

For encoders which support setting a quantization parameter (QP) for different frame types (I, P, B), they shall expose this API in addition to CODECAPI_AVEncVideoEncodeQP. If an encoder supports only a single QP for all frame types, they shall support only CODECAPI_AVEncVideoEncodeQP.

This is a dynamic encoding property meaning that a new value can be set any time during the encoding session.

H.264/AVC encoders:

Encoder shall support GetValue, SetValue, and GetParameterRange.

A set of four 16-bit fields are used to specify the frame QPs in fixed-QP encoding. The fields are:

• Bits 0-15: QP used for I frames, valid range [0, 51].
• Bits 16-31: QP used for P frames, valid range [0, 51].
• Bits 32-47: QP used for B frames, valid range [0, 51]
• Bits 48-63: reserved

When this CodecAPI is supported, encoders shall support QP setting on frame type of I, P, and B.

Default value shall be 0x0000001a001a001a. QP equal to 26 for I, P and B.

When CODECAPI_AVEncVideoSelectLayer selects a specific temporal layer, SetValue of CODECAPI_AVEncVideoEncodeFrameTypeQP shall set QP for I, P, and B frames on that temporal layer. By default, it sets QP for I, P, and B frames on base temporal layer temporal layer 0.

CODECAPI_AVEncVideoMaxQP and CODECAPI_AVEncVideoMinQP shall be used to define and limit the QP range for QPs of all picture types, I, P and B.

Requirements

See also

Media Foundation Properties