hi_venc_intra_refresh

Description

Defines the parameters for controlling Islice refresh in P-frames.

Prototype

typedef struct {
    hi_bool                    refresh_enable;
    hi_venc_intra_refresh_mode intra_refresh_mode;
    hi_u32                     refresh_num;
    hi_u32                     req_i_qp;
} hi_venc_intra_refresh;

Members

Member	Description
refresh_enable	Whether to enable the Islice refresh function. 0: disabled (default) 1: enabled.
intra_refresh_mode	I-macroblock refresh mode, by row or by column. By default, refresh by row is adopted.
refresh_num	Number of rows or columns refreshed for an I-macroblock each time. This variable controls the refresh speed and stream stability. A larger value indicates faster refresh and lower stream stability. A smaller value indicates slower refresh and higher stream stability. Ensure that the configured refresh_num can complete Islice refresh within a GOP. Note that in advanced frame skipping reference mode, Islice refresh is performed only in P-frames at the base layer (which can be referenced by other frames at the base layer). Table 1 lists the formulas for calculating the value of refresh_num.
req_i_qp	QP value of the I-frame. When hi_mpi_venc_set_intra_refresh and hi_mpi_venc_request_idr work together, this value is used to control the quality of the inserted IDR frame. A smaller value indicates better quality and a larger IDR frame size. The value range is [0, 51] and the default value is 51.

References

**Table 1** Formulas for calculating the value of **refresh_num**
-	Calculation Formula	Remarks
For H.264, the default value of refresh_num is as follows: (pic_height +lcu_size-1)>>6	Row: refresh_num x (max_refresh_frame_in_gop - 1) ≥ (pic_height + lcu_size - 1) /lcu_size Column: refresh_num x (max_refresh_frame_in_gop - 1) ≥ (pic_width + lcu_size - 1) /lcu_size In the formulas, / indicates rounding down.	max_refresh_frame_in_gop specifies the maximum number of P-frames for Islice refresh in a GOP, whose values are described as follows: If advanced frame skipping reference is not used: max_refresh_frame_in_gop = gop If advanced frame skipping reference is used: max_refresh_frame_in_gop = (gop + (base x (enhance+1) -1))/(base x (enhance+1)) The values of lcu_size (coding unit size) are described as follows: For H.264, this parameter has a fixed value of 16. For H.265:
For H.265, the default value of refresh_num is ((pic_height + lcu_size - 1)/lcu_size) >> 2.

Parent topic: VENC/JPEGE