[FFmpeg-cvslog] vc1dec: Partial rewrite of vc1_pred_mv()

shahriman AMS git at videolan.org
Thu Nov 10 03:58:59 CET 2011


ffmpeg | branch: master | shahriman AMS <shahriman_ams at yahoo.com> | Tue Nov  8 08:47:31 2011 +0000| [4344ce08f1d0b3ca90e60362ae4726e524dc85ba] | committer: Anton Khirnov

vc1dec: Partial rewrite of vc1_pred_mv()

The current code is a generalization of the earlier progressive MV
prediction code. This was supposed to predict MVs for both interlaced
and progressive pictures. But the interlaced MV prediction is buggy
and works mostly by luck.

This partially fixes interlaced MV prediction.

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

> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=4344ce08f1d0b3ca90e60362ae4726e524dc85ba
---

 libavcodec/vc1dec.c |  189 ++++++++++++++++++++++-----------------------------
 1 files changed, 80 insertions(+), 109 deletions(-)

diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c
index 5220104..f473b5d 100644
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@@ -1475,12 +1475,10 @@ static inline void vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
     int px, py;
     int sum;
     int mixedmv_pic, num_samefield = 0, num_oppfield = 0;
-    int opposit, f;
-    int16_t samefield_pred[2],  oppfield_pred[2];
-    int16_t samefield_predA[2], oppfield_predA[2];
-    int16_t samefield_predB[2], oppfield_predB[2];
-    int16_t samefield_predC[2], oppfield_predC[2];
-    int16_t *predA, *predC;
+    int opposit, a_f, b_f, c_f;
+    int16_t field_predA[2];
+    int16_t field_predB[2];
+    int16_t field_predC[2];
     int a_valid, b_valid, c_valid;
     int hybridmv_thresh, y_bias = 0;
 
@@ -1554,96 +1552,34 @@ static inline void vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
     }
 
     if (a_valid) {
-        f = v->mv_f[dir][xy - wrap + v->blocks_off];
-        num_oppfield  += f;
-        num_samefield += 1 - f;
-        if (f) {
-            oppfield_predA[0]  = A[0];
-            oppfield_predA[1]  = A[1];
-            samefield_predA[0] = scaleforsame(v, 0, A[0], 0, dir);
-            samefield_predA[1] = scaleforsame(v, n, A[1], 1, dir);
-        } else {
-            samefield_predA[0] = A[0];
-            samefield_predA[1] = A[1];
-            if (v->numref)
-                oppfield_predA[0] = scaleforopp(v, A[0], 0, dir);
-            if (v->numref)
-                oppfield_predA[1] = scaleforopp(v, A[1], 1, dir);
-        }
+        a_f = v->mv_f[dir][xy - wrap + v->blocks_off];
+        num_oppfield  += a_f;
+        num_samefield += 1 - a_f;
+        field_predA[0] = A[0];
+        field_predA[1] = A[1];
     } else {
-        samefield_predA[0] = samefield_predA[1] = 0;
-        oppfield_predA[0]  = oppfield_predA[1]  = 0;
+        field_predA[0] = field_predA[1] = 0;
+        a_f = 0;
     }
     if (c_valid) {
-        f = v->mv_f[dir][xy - 1 + v->blocks_off];
-        num_oppfield  += f;
-        num_samefield += 1 - f;
-        if (f) {
-            oppfield_predC[0]  = C[0];
-            oppfield_predC[1]  = C[1];
-            samefield_predC[0] = scaleforsame(v, 0, C[0], 0, dir);
-            samefield_predC[1] = scaleforsame(v, n, C[1], 1, dir);
-        } else {
-            samefield_predC[0] = C[0];
-            samefield_predC[1] = C[1];
-            if (v->numref)
-                oppfield_predC[0] = scaleforopp(v, C[0], 0, dir);
-            if (v->numref)
-                oppfield_predC[1] = scaleforopp(v, C[1], 1, dir);
-        }
+        c_f = v->mv_f[dir][xy - 1 + v->blocks_off];
+        num_oppfield  += c_f;
+        num_samefield += 1 - c_f;
+        field_predC[0] = C[0];
+        field_predC[1] = C[1];
     } else {
-        samefield_predC[0] = samefield_predC[1] = 0;
-        oppfield_predC[0]  = oppfield_predC[1]  = 0;
+        field_predC[0] = field_predC[1] = 0;
+        c_f = 0;
     }
     if (b_valid) {
-        f = v->mv_f[dir][xy - wrap + off + v->blocks_off];
-        num_oppfield  += f;
-        num_samefield += 1 - f;
-        if (f) {
-            oppfield_predB[0]  = B[0];
-            oppfield_predB[1]  = B[1];
-            samefield_predB[0] = scaleforsame(v, 0, B[0], 0, dir);
-            samefield_predB[1] = scaleforsame(v, n, B[1], 1, dir);
-        } else {
-            samefield_predB[0] = B[0];
-            samefield_predB[1] = B[1];
-            if (v->numref)
-                oppfield_predB[0] = scaleforopp(v, B[0], 0, dir);
-            if (v->numref)
-                oppfield_predB[1] = scaleforopp(v, B[1], 1, dir);
-        }
-    } else {
-        samefield_predB[0] = samefield_predB[1] = 0;
-        oppfield_predB[0]  = oppfield_predB[1]  = 0;
-    }
-
-    if (a_valid) {
-        samefield_pred[0] = samefield_predA[0];
-        samefield_pred[1] = samefield_predA[1];
-        oppfield_pred[0]  = oppfield_predA[0];
-        oppfield_pred[1]  = oppfield_predA[1];
-    } else if (c_valid) {
-        samefield_pred[0] = samefield_predC[0];
-        samefield_pred[1] = samefield_predC[1];
-        oppfield_pred[0]  = oppfield_predC[0];
-        oppfield_pred[1]  = oppfield_predC[1];
-    } else if (b_valid) {
-        samefield_pred[0] = samefield_predB[0];
-        samefield_pred[1] = samefield_predB[1];
-        oppfield_pred[0]  = oppfield_predB[0];
-        oppfield_pred[1]  = oppfield_predB[1];
+        b_f = v->mv_f[dir][xy - wrap + off + v->blocks_off];
+        num_oppfield  += b_f;
+        num_samefield += 1 - b_f;
+        field_predB[0] = B[0];
+        field_predB[1] = B[1];
     } else {
-        samefield_pred[0] = samefield_pred[1] = 0;
-        oppfield_pred[0]  = oppfield_pred[1]  = 0;
-    }
-
-    if (num_samefield + num_oppfield > 1) {
-        samefield_pred[0] = mid_pred(samefield_predA[0], samefield_predB[0], samefield_predC[0]);
-        samefield_pred[1] = mid_pred(samefield_predA[1], samefield_predB[1], samefield_predC[1]);
-        if (v->numref)
-            oppfield_pred[0] = mid_pred(oppfield_predA[0], oppfield_predB[0], oppfield_predC[0]);
-        if (v->numref)
-            oppfield_pred[1] = mid_pred(oppfield_predA[1], oppfield_predB[1], oppfield_predC[1]);
+        field_predB[0] = field_predB[1] = 0;
+        b_f = 0;
     }
 
     if (v->field_mode) {
@@ -1654,21 +1590,56 @@ static inline void vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
     } else
         opposit = 0;
     if (opposit) {
-        px    = oppfield_pred[0];
-        py    = oppfield_pred[1];
-        predA = oppfield_predA;
-        predC = oppfield_predC;
-        v->mv_f[dir][xy + v->blocks_off] = f = 1;
+        if (a_valid && !a_f) {
+            field_predA[0] = scaleforopp(v, field_predA[0], 0, dir);
+            field_predA[1] = scaleforopp(v, field_predA[1], 1, dir);
+        }
+        if (b_valid && !b_f) {
+            field_predB[0] = scaleforopp(v, field_predB[0], 0, dir);
+            field_predB[1] = scaleforopp(v, field_predB[1], 1, dir);
+        }
+        if (c_valid && !c_f) {
+            field_predC[0] = scaleforopp(v, field_predC[0], 0, dir);
+            field_predC[1] = scaleforopp(v, field_predC[1], 1, dir);
+        }
+        v->mv_f[dir][xy + v->blocks_off] = 1;
         v->ref_field_type[dir] = !v->cur_field_type;
     } else {
-        px    = samefield_pred[0];
-        py    = samefield_pred[1];
-        predA = samefield_predA;
-        predC = samefield_predC;
-        v->mv_f[dir][xy + v->blocks_off] = f = 0;
+        if (a_valid && a_f) {
+            field_predA[0] = scaleforsame(v, n, field_predA[0], 0, dir);
+            field_predA[1] = scaleforsame(v, n, field_predA[1], 1, dir);
+        }
+        if (b_valid && b_f) {
+            field_predB[0] = scaleforsame(v, n, field_predB[0], 0, dir);
+            field_predB[1] = scaleforsame(v, n, field_predB[1], 1, dir);
+        }
+        if (c_valid && c_f) {
+            field_predC[0] = scaleforsame(v, n, field_predC[0], 0, dir);
+            field_predC[1] = scaleforsame(v, n, field_predC[1], 1, dir);
+        }
+        v->mv_f[dir][xy + v->blocks_off] = 0;
         v->ref_field_type[dir] = v->cur_field_type;
     }
 
+    if (a_valid) {
+        px = field_predA[0];
+        py = field_predA[1];
+    } else if (c_valid) {
+        px = field_predC[0];
+        py = field_predC[1];
+    } else if (b_valid) {
+        px = field_predB[0];
+        py = field_predB[1];
+    } else {
+        px = 0;
+        py = 0;
+    }
+
+    if (num_samefield + num_oppfield > 1) {
+        px = mid_pred(field_predA[0], field_predB[0], field_predC[0]);
+        py = mid_pred(field_predA[1], field_predB[1], field_predC[1]);
+    }
+
     /* Pullback MV as specified in 8.3.5.3.4 */
     if (!v->field_mode) {
         int qx, qy, X, Y;
@@ -1697,27 +1668,27 @@ static inline void vc1_pred_mv(VC1Context *v, int n, int dmv_x, int dmv_y,
             if (is_intra[xy - wrap])
                 sum = FFABS(px) + FFABS(py);
             else
-                sum = FFABS(px - predA[0]) + FFABS(py - predA[1]);
+                sum = FFABS(px - field_predA[0]) + FFABS(py - field_predA[1]);
             if (sum > hybridmv_thresh) {
                 if (get_bits1(&s->gb)) {     // read HYBRIDPRED bit
-                    px = predA[0];
-                    py = predA[1];
+                    px = field_predA[0];
+                    py = field_predA[1];
                 } else {
-                    px = predC[0];
-                    py = predC[1];
+                    px = field_predC[0];
+                    py = field_predC[1];
                 }
             } else {
                 if (is_intra[xy - 1])
                     sum = FFABS(px) + FFABS(py);
                 else
-                    sum = FFABS(px - predC[0]) + FFABS(py - predC[1]);
+                    sum = FFABS(px - field_predC[0]) + FFABS(py - field_predC[1]);
                 if (sum > hybridmv_thresh) {
                     if (get_bits1(&s->gb)) {
-                        px = predA[0];
-                        py = predA[1];
+                        px = field_predA[0];
+                        py = field_predA[1];
                     } else {
-                        px = predC[0];
-                        py = predC[1];
+                        px = field_predC[0];
+                        py = field_predC[1];
                     }
                 }
             }



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