x264帧内预测-mb_analyse_intra

static void mb_analyse_intra( x264_t *h, x264_mb_analysis_t *a, int i_satd_inter )

//大致分为几个阶段

predict_16x16

mbcmp 比较残差

predict_8x8

mbcmp 比较残差

predict_4x4

mbcmp 比较残差

{

const int8_t *predict_mode = predict_16x16_mode_available( h->mb.i_neighbour_intra );

////获得可用的帧内预测模式-针对帧内16x16

 

/* Not heavily tuned */

static const uint8_t i16x16_thresh_lut[11] = { 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 4 };

int i16x16_thresh = a->b_fast_intra ? (i16x16_thresh_lut[h->mb.i_subpel_refine]*i_satd_inter)>>1 : COST_MAX;

for( ; *predict_mode >= 0; predict_mode++ )//遍历4种预测模式，计算代价

{

    int i_satd;

    int i_mode = *predict_mode;

 

   if( h->mb.b_lossless )

       x264_predict_lossless_16x16( h, 0, i_mode );

   else

  &n