+int64_t tm = 0, tn = 0;
+
+static int diff_vframe(VFrame &afrm, VFrame &bfrm)
+{
+ int n = 0, m = 0;
+ int w = afrm.get_w(), h = afrm.get_h();
+ uint8_t **arows = afrm.get_rows();
+ uint8_t **brows = bfrm.get_rows();
+
+ for( int y=0; y<h; ++y ) {
+ uint8_t *ap = arows[y], *bp = brows[y];
+ for( int x=0; x<w; ++x ) {
+ for( int i=0; i<3; ++i ) {
+ int d = *ap++ - *bp++;
+ m += d;
+ if( d < 0 ) d = -d;
+ n += d;
+ }
+ }
+ }
+ int sz = h*w*3;
+ printf(" %d %d %f", m, n, (double)n/sz);
+ tm += m; tn += n;
+ return n;
+}
+