hi_venc_h264_qvbr_param

说明

定义H.264协议编码通道QVBR码率控制模式的高级参数。

定义

hi_venc_h264_qvbr_param = {"max_i_proportion": max_i_proportion,
                           "min_i_proportion": min_i_proportion,
                           "max_reencode_times": max_reencode_times,
                           "qpmap_en": qpmap_en,
                           "max_qp": max_qp,
                           "min_qp": min_qp,
                           "max_i_qp": max_i_qp,
                           "min_i_qp": min_i_qp,
                           "max_bit_percent": max_bit_percent,
                           "min_bit_percent": min_bit_percent,
                           "max_psnr_fluctuate": max_psnr_fluctuate,
                           "min_psnr_fluctuate": min_psnr_fluctuate}

成员

当实时统计的PSNR小于“max_psnr_fluctuate”时，适当增加目标码率，最大码率 = target_bit_rate * max_bit_percent。

当实时统计的PSNR大于“max_psnr_fluctuate”时，适当减小目标码率，最小码率 = target_bit_rate * min_bit_percent。

根据当前PSNR的不同，目标码率会在最大码率和最小码率间调整，当PSNR值范围超过[min_psnr_fluctuate - 4, max_psnr_fluctuate + 4] ∩ [20, 40]时，PSNR不再起作用，码率会在最大码率和最小码率间调整。

“max_qp”，“min_qp”用于控制图像的质量范围，码率控制以QP钳位为最高优先级，超出“min_qp”，“max_qp”范围内码率控制将失效。

码率浮动上下限的优先级高于PSNR的优先级，例如，当码率浮动到上限依然不能满足PSNR要求，则码率不会再继续上调。