VC1: Fix first/last row checks with slices

In some places 0/mb_height were used in place of start_mb_y/end_mb_y.

Fixes SA00049, SA00058, SA10091, SA10097, SA10131, SA20021, SA30030

Improves PSNR in SA00054, SA00059, SA00060, SA10096, SA10098, SA20022,
SA30031, SA30032, SA40012, SA40013

Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
(cherry picked from commit 1cf82cab08)

Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/vc1dec.c

@@ -243,7 +243,7 @@ static void vc1_loop_filter_iblk(VC1Context *v, int pq)
     }
     v->vc1dsp.vc1_v_loop_filter16(s->dest[0] + 8*s->linesize, s->linesize, pq);
 
-    if (s->mb_y == s->mb_height-1) {
+    if (s->mb_y == s->end_mb_y-1) {
         if (s->mb_x) {
             v->vc1dsp.vc1_h_loop_filter16(s->dest[0], s->linesize, pq);
             v->vc1dsp.vc1_h_loop_filter8(s->dest[1], s->uvlinesize, pq);
@@ -295,7 +295,7 @@ static void vc1_loop_filter_iblk_delayed(VC1Context *v, int pq)
             v->vc1dsp.vc1_v_loop_filter16(s->dest[0] - 8 * s->linesize, s->linesize, pq);
         }
 
-        if (s->mb_y == s->mb_height) {
+        if (s->mb_y == s->end_mb_y) {
             if (s->mb_x) {
                 if (s->mb_x >= 2)
                     v->vc1dsp.vc1_h_loop_filter16(s->dest[0] - 16 * s->linesize - 16, s->linesize, pq);
@@ -2330,7 +2330,7 @@ static av_always_inline void vc1_apply_p_v_loop_filter(VC1Context *v, int block_
     } else {
         dst      = s->dest[0] + (block_num & 1) * 8 + ((block_num & 2) * 4 - 8) * linesize;
     }
-    if (s->mb_y != s->mb_height || block_num < 2) {
+    if (s->mb_y != s->end_mb_y || block_num < 2) {
         int16_t (*mv)[2];
         int mv_stride;
 
@@ -3096,7 +3096,7 @@ static void vc1_decode_i_blocks_adv(VC1Context *v)
         if(v->s.loop_filter) vc1_loop_filter_iblk_delayed(v, v->pq);
     }
     if (v->s.loop_filter)
-        ff_draw_horiz_band(s, (s->mb_height-1)*16, 16);
+        ff_draw_horiz_band(s, (s->end_mb_y-1)*16, 16);
     ff_er_add_slice(s, 0, s->start_mb_y, s->mb_width - 1, s->end_mb_y - 1, (AC_END|DC_END|MV_END));
 }
 
@@ -3219,7 +3219,7 @@ static void vc1_decode_b_blocks(VC1Context *v)
         s->first_slice_line = 0;
     }
     if (v->s.loop_filter)
-        ff_draw_horiz_band(s, (s->mb_height-1)*16, 16);
+        ff_draw_horiz_band(s, (s->end_mb_y-1)*16, 16);
     ff_er_add_slice(s, 0, s->start_mb_y, s->mb_width - 1, s->end_mb_y - 1, (AC_END|DC_END|MV_END));
 }
 
@@ -3227,9 +3227,9 @@ static void vc1_decode_skip_blocks(VC1Context *v)
 {
     MpegEncContext *s = &v->s;
 
-    ff_er_add_slice(s, 0, 0, s->mb_width - 1, s->mb_height - 1, (AC_END|DC_END|MV_END));
+    ff_er_add_slice(s, 0, s->start_mb_y, s->mb_width - 1, s->end_mb_y - 1, (AC_END|DC_END|MV_END));
     s->first_slice_line = 1;
-    for(s->mb_y = 0; s->mb_y < s->mb_height; s->mb_y++) {
+    for(s->mb_y = s->start_mb_y; s->mb_y < s->end_mb_y; s->mb_y++) {
         s->mb_x = 0;
         ff_init_block_index(s);
         ff_update_block_index(s);