bwdif-algorithm.txt

Spatial references:

     prefs3

     prefs
       x
     mrefs

     mrefs3

Temporal references:

prev2 prev cur next next2

prefs4             prefs4

prefs2             prefs2
      prefs   prefs
  0         x        0
      mrefs   mrefs
mrefs2             mrefs2

mrefs4             mrefs4

Spatial references:

      A

      B
      x
      C

      D

Temporal references:

a   j

b   k
 f h
c x l
 g i
d   m

e   n

#define FILTER_INTRA() \
    for (x = 0; x < w; x++) { \
        interpol = (coef_sp[0] * (cur[mrefs] + cur[prefs]) - coef_sp[1] * (cur[mrefs3] + cur[prefs3])) >> 13; \
        dst[0] = av_clip(interpol, 0, clip_max); \
 \
        dst++; \
        cur++; \
    }



define FILTER1() \
    for (x = 0; x < w; x++) { \
        int c = cur[mrefs]; \
        int d = (prev2[0] + next2[0]) >> 1; \
        int e = cur[prefs]; \
        int temporal_diff0 = FFABS(prev2[0] - next2[0]); \
        int temporal_diff1 =(FFABS(prev[mrefs] - c) + FFABS(prev[prefs] - e)) >> 1; \
        int temporal_diff2 =(FFABS(next[mrefs] - c) + FFABS(next[prefs] - e)) >> 1; \
        int diff = FFMAX3(temporal_diff0 >> 1, temporal_diff1, temporal_diff2); \
 \
        if (!diff) { \
            dst[0] = d; \
        } else {

#define SPAT_CHECK() \
            int b = ((prev2[mrefs2] + next2[mrefs2]) >> 1) - c; \
            int f = ((prev2[prefs2] + next2[prefs2]) >> 1) - e; \
            int dc = d - c; \
            int de = d - e; \
            int max = FFMAX3(de, dc, FFMIN(b, f)); \
            int min = FFMIN3(de, dc, FFMAX(b, f)); \
            diff = FFMAX3(diff, min, -max);

#define FILTER_LINE() \
            SPAT_CHECK() \
            if (FFABS(c - e) > temporal_diff0) { \
                interpol = (((coef_hf[0] * (prev2[0] + next2[0]) \
                    - coef_hf[1] * (prev2[mrefs2] + next2[mrefs2] + prev2[prefs2] + next2[prefs2]) \
                    + coef_hf[2] * (prev2[mrefs4] + next2[mrefs4] + prev2[prefs4] + next2[prefs4])) >> 2) \
                    + coef_lf[0] * (c + e) - coef_lf[1] * (cur[mrefs3] + cur[prefs3])) >> 13; \
            } else { \
                interpol = (coef_sp[0] * (c + e) - coef_sp[1] * (cur[mrefs3] + cur[prefs3])) >> 13; \
            }

#define FILTER_EDGE() \
            if (spat) { \
                SPAT_CHECK() \
            } \
            interpol = (c + e) >> 1;

#define FILTER2() \
            if (interpol > d + diff) \
                interpol = d + diff; \
            else if (interpol < d - diff) \
                interpol = d - diff; \
 \
            dst[0] = av_clip(interpol, 0, clip_max); \
        } \