编码器的参数设定 X264

void  x264_param_default( x264_param_t *param )

{……

    /* Video properties */

    param->i_csp           = X264_CSP_I420;

    param->i_width         = 352;

    param->i_height        = 288;

    param->vui.i_sar_width = 0;

    param->vui.i_sar_height= 0;

    param->i_fps_num       = 25;

    param->i_fps_den       = 1;

    param->i_level_idc     = 40; /* level 4.0 is sufficient for 720x576 with16 reference frames */

    /* Encoder parameters */

    param->i_frame_reference = 1;//参考帧的个数

    param->i_keyint_max = 250;//最大IDR帧间距，默认250

    param->i_keyint_min = 25;//最小IDR帧间距，默认25

    param->i_bframe = 0;// 在IP帧之间可插入的B帧数量最大值，范围0~16，默认0

    param->i_scenecut_threshold =40;// 画面动态变化限，当超出此值时插入I帧，默认40

    param->b_bframe_adaptive = 0;//好像是自适应的B帧个数

    param->i_bframe_bias = 0;// 控制插入B帧判定，范围-100~+100，越高越容易插入B帧，默认0

    param->b_bframe_pyramid = 0; //允许B帧做参考帧

 

    param->b_deblocking_filter = 0;

    param->i_deblocking_filter_alphac0 = 0;

    param->i_deblocking_filter_beta = 0;

 

    param->b_cabac = 0;

    param->i_cabac_init_idc = -1;

 

    param->rc.b_cbr = 0;//是否使用码率控制

    param->rc.i_bitrate = 1000;

    param->rc.f_rate_tolerance = 1.0;

    param->rc.i_vbv_max_bitrate = 0;

    param->rc.i_vbv_buffer_size = 0;

    param->rc.f_vbv_buffer_init = 0.9;

    param->rc.i_qp_constant = 30;

    param->rc.i_qp_min = 20;

    param->rc.i_qp_max = 51;

    param->rc.i_qp_step = 4;

    param->rc.f_ip_factor = 1.4;

    param->rc.f_pb_factor = 1.3;

 

    param->rc.b_stat_write = 0;

    param->rc.psz_stat_out = "x264_2pass.log";

    param->rc.b_stat_read = 0;

    param->rc.psz_stat_in = "x264_2pass.log";

    param->rc.psz_rc_eq = "blurCplx^(1-qComp)";

    param->rc.f_qcompress = 1.0;

    param->rc.f_qblur = 1.0;

    param->rc.f_complexity_blur = 20;

 

    /* Log */

    param->pf_log = x264_log_default;

    param->p_log_private = NULL;

    param->i_log_level = X264_LOG_NONE;

 

    /* */

    param->analyse.intra = X264_ANALYSE_I4x4;// 帧内预测模式

    param->analyse.inter = X264_ANALYSE_I4x4 | X264_ANALYSE_PSUB16x16 | X264_ANALYSE_BSUB16x16; // 帧间预测模式

    param->analyse.i_direct_mv_pred = X264_DIRECT_PRED_TEMPORAL;

    param->analyse.i_me_method = X264_ME_DIA;//好像是运动补偿的算法选择

    param->analyse.i_me_range = 8; // me为umh/esa时的搜索半径（以像素位单位），最大64，默认16

    param->analyse.i_subpel_refine = 3;//亚像素搜索范围

    param->analyse.b_chroma_me = 1;

    param->analyse.i_mv_range = 512;//运动向量搜索范围

    param->analyse.i_chroma_qp_offset = 0;//色度和亮度之间的量化差,范围-12~+12，默认0

    param->analyse.b_psnr = 0;//是否使用信噪比

 

    param->b_aud = 0;

}