avcodec/hevc: Fix modulo operations

Fixes qp fields becoming out of range
Fixes: asan_static-oob_e393a3_6998_WPP_A_ericsson_MAIN10_2.bit
Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/hevc.c

@@ -688,8 +688,8 @@ static int hls_slice_header(HEVCContext *s)
     s->HEVClc->first_qp_group = !s->sh.dependent_slice_segment_flag;
 
     if (!s->pps->cu_qp_delta_enabled_flag)
-        s->HEVClc->qp_y = ((s->sh.slice_qp + 52 + 2 * s->sps->qp_bd_offset) %
-                          (52 + s->sps->qp_bd_offset)) - s->sps->qp_bd_offset;
+        s->HEVClc->qp_y = FFUMOD(s->sh.slice_qp + 52 + 2 * s->sps->qp_bd_offset,
+                                 52 + s->sps->qp_bd_offset) - s->sps->qp_bd_offset;
 
     s->slice_initialized = 1;
 

libavcodec/hevc_filter.c

@@ -160,8 +160,8 @@ void ff_hevc_set_qPy(HEVCContext *s, int xC, int yC,
 
     if (s->HEVClc->tu.cu_qp_delta != 0) {
         int off = s->sps->qp_bd_offset;
-        s->HEVClc->qp_y = ((qp_y + s->HEVClc->tu.cu_qp_delta + 52 + 2 * off) %
-                          (52 + off)) - off;
+        s->HEVClc->qp_y = FFUMOD(qp_y + s->HEVClc->tu.cu_qp_delta + 52 + 2 * off,
+                                 52 + off) - off;
     } else
         s->HEVClc->qp_y = qp_y;
 }