decode: Simplify read_mv_residual()

1 files changed, 29 insertions, 51 deletions

diff --git a/src/decode.c b/src/decode.c
index f6d9104..7427c35 100644
--- a/src/decode.c
+++ b/src/decode.c
@@ -73,42 +73,29 @@ static void init_quant_tables(const Dav1dSequenceHeader *const seq_hdr,
     }
 }
 
-static int read_mv_component_diff(Dav1dTaskContext *const t,
+static int read_mv_component_diff(MsacContext *const msac,
                                   CdfMvComponent *const mv_comp,
-                                  const int have_fp)
+                                  const int mv_prec)
 {
-    Dav1dTileState *const ts = t->ts;
-    const Dav1dFrameContext *const f = t->f;
-    const int have_hp = f->frame_hdr->hp;
-    const int sign = dav1d_msac_decode_bool_adapt(&ts->msac, mv_comp->sign);
-    const int cl = dav1d_msac_decode_symbol_adapt16(&ts->msac,
-                                                    mv_comp->classes, 10);
-    int up, fp, hp;
+    const int sign = dav1d_msac_decode_bool_adapt(msac, mv_comp->sign);
+    const int cl = dav1d_msac_decode_symbol_adapt16(msac, mv_comp->classes, 10);
+    int up, fp = 3, hp = 1;
 
     if (!cl) {
-        up = dav1d_msac_decode_bool_adapt(&ts->msac, mv_comp->class0);
-        if (have_fp) {
-            fp = dav1d_msac_decode_symbol_adapt4(&ts->msac,
-                                                 mv_comp->class0_fp[up], 3);
-            hp = have_hp ? dav1d_msac_decode_bool_adapt(&ts->msac,
-                                                        mv_comp->class0_hp) : 1;
-        } else {
-            fp = 3;
-            hp = 1;
+        up = dav1d_msac_decode_bool_adapt(msac, mv_comp->class0);
+        if (mv_prec >= 0) {  // !force_integer_mv
+            fp = dav1d_msac_decode_symbol_adapt4(msac, mv_comp->class0_fp[up], 3);
+            if (mv_prec > 0) // allow_high_precision_mv
+                hp = dav1d_msac_decode_bool_adapt(msac, mv_comp->class0_hp);
         }
     } else {
         up = 1 << cl;
         for (int n = 0; n < cl; n++)
-            up |= dav1d_msac_decode_bool_adapt(&ts->msac,
-                                               mv_comp->classN[n]) << n;
-        if (have_fp) {
-            fp = dav1d_msac_decode_symbol_adapt4(&ts->msac,
-                                                 mv_comp->classN_fp, 3);
-            hp = have_hp ? dav1d_msac_decode_bool_adapt(&ts->msac,
-                                                        mv_comp->classN_hp) : 1;
-        } else {
-            fp = 3;
-            hp = 1;
+            up |= dav1d_msac_decode_bool_adapt(msac, mv_comp->classN[n]) << n;
+        if (mv_prec >= 0) {  // !force_integer_mv
+            fp = dav1d_msac_decode_symbol_adapt4(msac, mv_comp->classN_fp, 3);
+            if (mv_prec > 0) // allow_high_precision_mv
+                hp = dav1d_msac_decode_bool_adapt(msac, mv_comp->classN_hp);
         }
     }
 
@@ -117,25 +104,16 @@ static int read_mv_component_diff(Dav1dTaskContext *const t,
     return sign ? -diff : diff;
 }
 
-static void read_mv_residual(Dav1dTaskContext *const t, mv *const ref_mv,
-                             CdfMvContext *const mv_cdf, const int have_fp)
+static void read_mv_residual(Dav1dTileState *const ts, mv *const ref_mv,
+                             const int mv_prec)
 {
-    switch (dav1d_msac_decode_symbol_adapt4(&t->ts->msac, t->ts->cdf.mv.joint,
-                                            N_MV_JOINTS - 1))
-    {
-    case MV_JOINT_HV:
-        ref_mv->y += read_mv_component_diff(t, &mv_cdf->comp[0], have_fp);
-        ref_mv->x += read_mv_component_diff(t, &mv_cdf->comp[1], have_fp);
-        break;
-    case MV_JOINT_H:
-        ref_mv->x += read_mv_component_diff(t, &mv_cdf->comp[1], have_fp);
-        break;
-    case MV_JOINT_V:
-        ref_mv->y += read_mv_component_diff(t, &mv_cdf->comp[0], have_fp);
-        break;
-    default:
-        break;
-    }
+    MsacContext *const msac = &ts->msac;
+    const enum MVJoint mv_joint =
+        dav1d_msac_decode_symbol_adapt4(msac, ts->cdf.mv.joint, N_MV_JOINTS - 1);
+    if (mv_joint & MV_JOINT_V)
+        ref_mv->y += read_mv_component_diff(msac, &ts->cdf.mv.comp[0], mv_prec);
+    if (mv_joint & MV_JOINT_H)
+        ref_mv->x += read_mv_component_diff(msac, &ts->cdf.mv.comp[1], mv_prec);
 }
 
 static void read_tx_tree(Dav1dTaskContext *const t,
@@ -1323,7 +1301,7 @@ static int decode_b(Dav1dTaskContext *const t,
         }
 
         const union mv ref = b->mv[0];
-        read_mv_residual(t, &b->mv[0], &ts->cdf.mv, 0);
+        read_mv_residual(ts, &b->mv[0], -1);
 
         // clip intrabc motion vector to decoded parts of current tile
         int border_left = ts->tiling.col_start * 4;
@@ -1585,8 +1563,8 @@ static int decode_b(Dav1dTaskContext *const t,
                 break; \
             case NEWMV: \
                 b->mv[idx] = mvstack[b->drl_idx].mv.mv[idx]; \
-                read_mv_residual(t, &b->mv[idx], &ts->cdf.mv, \
-                                 !f->frame_hdr->force_integer_mv); \
+                const int mv_prec = f->frame_hdr->hp - f->frame_hdr->force_integer_mv; \
+                read_mv_residual(ts, &b->mv[idx], mv_prec); \
                 break; \
             }
             has_subpel_filter = imin(bw4, bh4) == 1 ||
@@ -1774,8 +1752,8 @@ static int decode_b(Dav1dTaskContext *const t,
                 if (DEBUG_BLOCK_INFO)
                     printf("Post-intermode[%d,drl=%d]: r=%d\n",
                            b->inter_mode, b->drl_idx, ts->msac.rng);
-                read_mv_residual(t, &b->mv[0], &ts->cdf.mv,
-                                 !f->frame_hdr->force_integer_mv);
+                const int mv_prec = f->frame_hdr->hp - f->frame_hdr->force_integer_mv;
+                read_mv_residual(ts, &b->mv[0], mv_prec);
                 if (DEBUG_BLOCK_INFO)
                     printf("Post-residualmv[mv=y:%d,x:%d]: r=%d\n",
                            b->mv[0].y, b->mv[0].x, ts->msac.rng);