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simplification

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Originally committed as revision 5794 to svn://svn.ffmpeg.org/ffmpeg/trunk
This commit is contained in:
Michael Niedermayer 2006-07-19 21:20:56 +00:00
parent 09eb00f6b5
commit f72f8a7735
1 changed files with 21 additions and 114 deletions
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135
libavcodec/vp3.c
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@ -1367,19 +1367,6 @@ static void reverse_dc_prediction(Vp3DecodeContext *s,
int x, y;
int i = first_fragment;
/*
* Fragment prediction groups:
*
* 32222222226
* 10000000004
* 10000000004
* 10000000004
* 10000000004
*
* Note: Groups 5 and 7 do not exist as it would mean that the
* fragment's x coordinate is both 0 and (width - 1) at the same time.
*/
int predictor_group;
short predicted_dc;
/* validity flags for the left, up-left, up, and up-right fragments */
@ -1458,113 +1445,33 @@ static void reverse_dc_prediction(Vp3DecodeContext *s,
current_frame_type =
compatible_frame[s->all_fragments[i].coding_method];
predictor_group = (x == 0) + ((y == 0) << 1) +
((x + 1 == fragment_width) << 2);
debug_dc_pred(" frag %d: group %d, orig DC = %d, ",
i, predictor_group, DC_COEFF(i));
i, -1, DC_COEFF(i));
switch (predictor_group) {
case 0:
/* main body of fragments; consider all 4 possible
* fragments for prediction */
/* calculate the indices of the predicting fragments */
ul = i - fragment_width - 1;
u = i - fragment_width;
ur = i - fragment_width + 1;
l = i - 1;
/* fetch the DC values for the predicting fragments */
transform= 0;
if(x){
l= i-1;
vl = DC_COEFF(l);
fl = FRAME_CODED(l) && COMPATIBLE_FRAME(l);
transform |= fl*PL;
}
if(y){
u= i-fragment_width;
vu = DC_COEFF(u);
fu = FRAME_CODED(u) && COMPATIBLE_FRAME(u);
transform |= fu*PU;
if(x){
ul= i-fragment_width-1;
vul = DC_COEFF(ul);
vu = DC_COEFF(u);
vur = DC_COEFF(ur);
vl = DC_COEFF(l);
/* figure out which fragments are valid */
ful = FRAME_CODED(ul) && COMPATIBLE_FRAME(ul);
fu = FRAME_CODED(u) && COMPATIBLE_FRAME(u);
fur = FRAME_CODED(ur) && COMPATIBLE_FRAME(ur);
fl = FRAME_CODED(l) && COMPATIBLE_FRAME(l);
/* decide which predictor transform to use */
transform = (fl*PL) | (fu*PU) | (ful*PUL) | (fur*PUR);
break;
case 1:
/* left column of fragments, not including top corner;
* only consider up and up-right fragments */
/* calculate the indices of the predicting fragments */
u = i - fragment_width;
ur = i - fragment_width + 1;
/* fetch the DC values for the predicting fragments */
vu = DC_COEFF(u);
transform |= ful*PUL;
}
if(x + 1 < fragment_width){
ur= i-fragment_width+1;
vur = DC_COEFF(ur);
/* figure out which fragments are valid */
fur = FRAME_CODED(ur) && COMPATIBLE_FRAME(ur);
fu = FRAME_CODED(u) && COMPATIBLE_FRAME(u);
/* decide which predictor transform to use */
transform = (fu*PU) | (fur*PUR);
break;
case 2:
case 6:
/* top row of fragments, not including top-left frag;
* only consider the left fragment for prediction */
/* calculate the indices of the predicting fragments */
l = i - 1;
/* fetch the DC values for the predicting fragments */
vl = DC_COEFF(l);
/* figure out which fragments are valid */
fl = FRAME_CODED(l) && COMPATIBLE_FRAME(l);
/* decide which predictor transform to use */
transform = (fl*PL);
break;
case 3:
/* top-left fragment */
/* nothing to predict from in this case */
transform = 0;
break;
case 4:
/* right column of fragments, not including top corner;
* consider up-left, up, and left fragments for
* prediction */
/* calculate the indices of the predicting fragments */
ul = i - fragment_width - 1;
u = i - fragment_width;
l = i - 1;
/* fetch the DC values for the predicting fragments */
vul = DC_COEFF(ul);
vu = DC_COEFF(u);
vl = DC_COEFF(l);
/* figure out which fragments are valid */
ful = FRAME_CODED(ul) && COMPATIBLE_FRAME(ul);
fu = FRAME_CODED(u) && COMPATIBLE_FRAME(u);
fl = FRAME_CODED(l) && COMPATIBLE_FRAME(l);
/* decide which predictor transform to use */
transform = (fl*PL) | (fu*PU) | (ful*PUL);
break;
transform |= fur*PUR;
}
}
debug_dc_pred("transform = %d, ", transform);