]> git.sesse.net Git - ffmpeg/blobdiff - libavcodec/h264_mvpred.h
h264: fix invalid pointer arithmetic
[ffmpeg] / libavcodec / h264_mvpred.h
index f603e7ff381d0252ebbd261f3f0c21902af16e9d..5244c290f2acf76ea7b8a50ad32e0fe12aac86c8 100644 (file)
 //#undef NDEBUG
 #include <assert.h>
 
-static inline int fetch_diagonal_mv(H264Context *h, const int16_t **C, int i, int list, int part_width){
-    const int topright_ref= h->ref_cache[list][ i - 8 + part_width ];
-    MpegEncContext *s = &h->s;
+static av_always_inline int fetch_diagonal_mv(H264Context *h, const int16_t **C,
+                                              int i, int list, int part_width)
+{
+    const int topright_ref = h->ref_cache[list][i - 8 + part_width];
+    MpegEncContext *s      = &h->s;
 
     /* there is no consistent mapping of mvs to neighboring locations that will
      * make mbaff happy, so we can't move all this logic to fill_caches */
-    if(FRAME_MBAFF){
-
-#define SET_DIAG_MV(MV_OP, REF_OP, XY, Y4)\
-                const int xy = XY, y4 = Y4;\
-                const int mb_type = mb_types[xy+(y4>>2)*s->mb_stride];\
-                if(!USES_LIST(mb_type,list))\
-                    return LIST_NOT_USED;\
-                mv = s->current_picture_ptr->motion_val[list][h->mb2b_xy[xy]+3 + y4*h->b_stride];\
-                h->mv_cache[list][scan8[0]-2][0] = mv[0];\
-                h->mv_cache[list][scan8[0]-2][1] = mv[1] MV_OP;\
-                return s->current_picture_ptr->ref_index[list][4*xy+1 + (y4&~1)] REF_OP;
-
-        if(topright_ref == PART_NOT_AVAILABLE
-           && i >= scan8[0]+8 && (i&7)==4
-           && h->ref_cache[list][scan8[0]-1] != PART_NOT_AVAILABLE){
-            const uint32_t *mb_types = s->current_picture_ptr->mb_type;
+    if (FRAME_MBAFF) {
+#define SET_DIAG_MV(MV_OP, REF_OP, XY, Y4)                              \
+        const int xy = XY, y4 = Y4;                                     \
+        const int mb_type = mb_types[xy + (y4 >> 2) * s->mb_stride];    \
+        if (!USES_LIST(mb_type, list))                                  \
+            return LIST_NOT_USED;                                       \
+        mv = s->current_picture_ptr->f.motion_val[list][h->mb2b_xy[xy] + 3 + y4 * h->b_stride]; \
+        h->mv_cache[list][scan8[0] - 2][0] = mv[0];                     \
+        h->mv_cache[list][scan8[0] - 2][1] = mv[1] MV_OP;               \
+        return s->current_picture_ptr->f.ref_index[list][4 * xy + 1 + (y4 & ~1)] REF_OP;
+
+        if (topright_ref == PART_NOT_AVAILABLE
+            && i >= scan8[0] + 8 && (i & 7) == 4
+            && h->ref_cache[list][scan8[0] - 1] != PART_NOT_AVAILABLE) {
+            const uint32_t *mb_types = s->current_picture_ptr->f.mb_type;
             const int16_t *mv;
-            AV_ZERO32(h->mv_cache[list][scan8[0]-2]);
-            *C = h->mv_cache[list][scan8[0]-2];
+            AV_ZERO32(h->mv_cache[list][scan8[0] - 2]);
+            *C = h->mv_cache[list][scan8[0] - 2];
 
-            if(!MB_FIELD
-               && IS_INTERLACED(h->left_type[0])){
-                SET_DIAG_MV(*2, >>1, h->left_mb_xy[0]+s->mb_stride, (s->mb_y&1)*2+(i>>5));
+            if (!MB_FIELD && IS_INTERLACED(h->left_type[0])) {
+                SET_DIAG_MV(* 2, >> 1, h->left_mb_xy[0] + s->mb_stride,
+                            (s->mb_y & 1) * 2 + (i >> 5));
             }
-            if(MB_FIELD
-               && !IS_INTERLACED(h->left_type[0])){
+            if (MB_FIELD && !IS_INTERLACED(h->left_type[0])) {
                 // left shift will turn LIST_NOT_USED into PART_NOT_AVAILABLE, but that's OK.
-                SET_DIAG_MV(/2, <<1, h->left_mb_xy[i>=36], ((i>>2))&3);
+                SET_DIAG_MV(/ 2, << 1, h->left_mb_xy[i >= 36], ((i >> 2)) & 3);
             }
         }
 #undef SET_DIAG_MV
     }
 
-    if(topright_ref != PART_NOT_AVAILABLE){
-        *C= h->mv_cache[list][ i - 8 + part_width ];
+    if (topright_ref != PART_NOT_AVAILABLE) {
+        *C = h->mv_cache[list][i - 8 + part_width];
         return topright_ref;
-    }else{
+    } else {
         tprintf(s->avctx, "topright MV not available\n");
 
-        *C= h->mv_cache[list][ i - 8 - 1 ];
-        return h->ref_cache[list][ i - 8 - 1 ];
+        *C = h->mv_cache[list][i - 8 - 1];
+        return h->ref_cache[list][i - 8 - 1];
     }
 }
 
 /**
- * gets the predicted MV.
+ * Get the predicted MV.
  * @param n the block index
  * @param part_width the width of the partition (4, 8,16) -> (1, 2, 4)
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
-static inline void pred_motion(H264Context * const h, int n, int part_width, int list, int ref, int * const mx, int * const my){
-    const int index8= scan8[n];
-    const int top_ref=      h->ref_cache[list][ index8 - 8 ];
-    const int left_ref=     h->ref_cache[list][ index8 - 1 ];
-    const int16_t * const A= h->mv_cache[list][ index8 - 1 ];
-    const int16_t * const B= h->mv_cache[list][ index8 - 8 ];
-    const int16_t * C;
+static av_always_inline void pred_motion(H264Context *const h, int n,
+                                         int part_width, int list, int ref,
+                                         int *const mx, int *const my)
+{
+    const int index8       = scan8[n];
+    const int top_ref      = h->ref_cache[list][index8 - 8];
+    const int left_ref     = h->ref_cache[list][index8 - 1];
+    const int16_t *const A = h->mv_cache[list][index8 - 1];
+    const int16_t *const B = h->mv_cache[list][index8 - 8];
+    const int16_t *C;
     int diagonal_ref, match_count;
 
-    assert(part_width==1 || part_width==2 || part_width==4);
+    assert(part_width == 1 || part_width == 2 || part_width == 4);
 
 /* mv_cache
-  B . . A T T T T
-  U . . L . . , .
-  U . . L . . . .
-  U . . L . . , .
-  . . . L . . . .
-*/
-
-    diagonal_ref= fetch_diagonal_mv(h, &C, index8, list, part_width);
-    match_count= (diagonal_ref==ref) + (top_ref==ref) + (left_ref==ref);
* B . . A T T T T
* U . . L . . , .
* U . . L . . . .
* U . . L . . , .
* . . . L . . . .
+ */
+
+    diagonal_ref = fetch_diagonal_mv(h, &C, index8, list, part_width);
+    match_count  = (diagonal_ref == ref) + (top_ref == ref) + (left_ref == ref);
     tprintf(h->s.avctx, "pred_motion match_count=%d\n", match_count);
-    if(match_count > 1){ //most common
-        *mx= mid_pred(A[0], B[0], C[0]);
-        *my= mid_pred(A[1], B[1], C[1]);
-    }else if(match_count==1){
-        if(left_ref==ref){
-            *mx= A[0];
-            *my= A[1];
-        }else if(top_ref==ref){
-            *mx= B[0];
-            *my= B[1];
-        }else{
-            *mx= C[0];
-            *my= C[1];
-        }
-    }else{
-        if(top_ref == PART_NOT_AVAILABLE && diagonal_ref == PART_NOT_AVAILABLE && left_ref != PART_NOT_AVAILABLE){
-            *mx= A[0];
-            *my= A[1];
-        }else{
-            *mx= mid_pred(A[0], B[0], C[0]);
-            *my= mid_pred(A[1], B[1], C[1]);
-        }
-    }
-
-    tprintf(h->s.avctx, "pred_motion (%2d %2d %2d) (%2d %2d %2d) (%2d %2d %2d) -> (%2d %2d %2d) at %2d %2d %d list %d\n", top_ref, B[0], B[1],                    diagonal_ref, C[0], C[1], left_ref, A[0], A[1], ref, *mx, *my, h->s.mb_x, h->s.mb_y, n, list);
+    if (match_count > 1) { //most common
+        *mx = mid_pred(A[0], B[0], C[0]);
+        *my = mid_pred(A[1], B[1], C[1]);
+    } else if (match_count == 1) {
+        if (left_ref == ref) {
+            *mx = A[0];
+            *my = A[1];
+        } else if (top_ref == ref) {
+            *mx = B[0];
+            *my = B[1];
+        } else {
+            *mx = C[0];
+            *my = C[1];
+        }
+    } else {
+        if (top_ref      == PART_NOT_AVAILABLE &&
+            diagonal_ref == PART_NOT_AVAILABLE &&
+            left_ref     != PART_NOT_AVAILABLE) {
+            *mx = A[0];
+            *my = A[1];
+        } else {
+            *mx = mid_pred(A[0], B[0], C[0]);
+            *my = mid_pred(A[1], B[1], C[1]);
+        }
+    }
+
+    tprintf(h->s.avctx,
+            "pred_motion (%2d %2d %2d) (%2d %2d %2d) (%2d %2d %2d) -> (%2d %2d %2d) at %2d %2d %d list %d\n",
+            top_ref, B[0], B[1], diagonal_ref, C[0], C[1], left_ref,
+            A[0], A[1], ref, *mx, *my, h->s.mb_x, h->s.mb_y, n, list);
 }
 
 /**
- * gets the directionally predicted 16x8 MV.
+ * Get the directionally predicted 16x8 MV.
  * @param n the block index
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
-static inline void pred_16x8_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
-    if(n==0){
-        const int top_ref=      h->ref_cache[list][ scan8[0] - 8 ];
-        const int16_t * const B= h->mv_cache[list][ scan8[0] - 8 ];
-
-        tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n", top_ref, B[0], B[1], h->s.mb_x, h->s.mb_y, n, list);
-
-        if(top_ref == ref){
-            *mx= B[0];
-            *my= B[1];
+static av_always_inline void pred_16x8_motion(H264Context *const h,
+                                              int n, int list, int ref,
+                                              int *const mx, int *const my)
+{
+    if (n == 0) {
+        const int top_ref      = h->ref_cache[list][scan8[0] - 8];
+        const int16_t *const B = h->mv_cache[list][scan8[0] - 8];
+
+        tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n",
+                top_ref, B[0], B[1], h->s.mb_x, h->s.mb_y, n, list);
+
+        if (top_ref == ref) {
+            *mx = B[0];
+            *my = B[1];
             return;
         }
-    }else{
-        const int left_ref=     h->ref_cache[list][ scan8[8] - 1 ];
-        const int16_t * const A= h->mv_cache[list][ scan8[8] - 1 ];
+    } else {
+        const int left_ref     = h->ref_cache[list][scan8[8] - 1];
+        const int16_t *const A = h->mv_cache[list][scan8[8] - 1];
 
-        tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n", left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
+        tprintf(h->s.avctx, "pred_16x8: (%2d %2d %2d) at %2d %2d %d list %d\n",
+                left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
 
-        if(left_ref == ref){
-            *mx= A[0];
-            *my= A[1];
+        if (left_ref == ref) {
+            *mx = A[0];
+            *my = A[1];
             return;
         }
     }
@@ -177,34 +190,39 @@ static inline void pred_16x8_motion(H264Context * const h, int n, int list, int
 }
 
 /**
- * gets the directionally predicted 8x16 MV.
+ * Get the directionally predicted 8x16 MV.
  * @param n the block index
  * @param mx the x component of the predicted motion vector
  * @param my the y component of the predicted motion vector
  */
-static inline void pred_8x16_motion(H264Context * const h, int n, int list, int ref, int * const mx, int * const my){
-    if(n==0){
-        const int left_ref=      h->ref_cache[list][ scan8[0] - 1 ];
-        const int16_t * const A=  h->mv_cache[list][ scan8[0] - 1 ];
-
-        tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n", left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
-
-        if(left_ref == ref){
-            *mx= A[0];
-            *my= A[1];
+static av_always_inline void pred_8x16_motion(H264Context *const h,
+                                              int n, int list, int ref,
+                                              int *const mx, int *const my)
+{
+    if (n == 0) {
+        const int left_ref     = h->ref_cache[list][scan8[0] - 1];
+        const int16_t *const A = h->mv_cache[list][scan8[0] - 1];
+
+        tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n",
+                left_ref, A[0], A[1], h->s.mb_x, h->s.mb_y, n, list);
+
+        if (left_ref == ref) {
+            *mx = A[0];
+            *my = A[1];
             return;
         }
-    }else{
-        const int16_t * C;
+    } else {
+        const int16_t *C;
         int diagonal_ref;
 
-        diagonal_ref= fetch_diagonal_mv(h, &C, scan8[4], list, 2);
+        diagonal_ref = fetch_diagonal_mv(h, &C, scan8[4], list, 2);
 
-        tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n", diagonal_ref, C[0], C[1], h->s.mb_x, h->s.mb_y, n, list);
+        tprintf(h->s.avctx, "pred_8x16: (%2d %2d %2d) at %2d %2d %d list %d\n",
+                diagonal_ref, C[0], C[1], h->s.mb_x, h->s.mb_y, n, list);
 
-        if(diagonal_ref == ref){
-            *mx= C[0];
-            *my= C[1];
+        if (diagonal_ref == ref) {
+            *mx = C[0];
+            *my = C[1];
             return;
         }
     }
@@ -213,23 +231,605 @@ static inline void pred_8x16_motion(H264Context * const h, int n, int list, int
     pred_motion(h, n, 2, list, ref, mx, my);
 }
 
-static inline void pred_pskip_motion(H264Context * const h, int * const mx, int * const my){
-    const int top_ref = h->ref_cache[0][ scan8[0] - 8 ];
-    const int left_ref= h->ref_cache[0][ scan8[0] - 1 ];
+#define FIX_MV_MBAFF(type, refn, mvn, idx)      \
+    if (FRAME_MBAFF) {                          \
+        if (MB_FIELD) {                         \
+            if (!IS_INTERLACED(type)) {         \
+                refn <<= 1;                     \
+                AV_COPY32(mvbuf[idx], mvn);     \
+                mvbuf[idx][1] /= 2;             \
+                mvn = mvbuf[idx];               \
+            }                                   \
+        } else {                                \
+            if (IS_INTERLACED(type)) {          \
+                refn >>= 1;                     \
+                AV_COPY32(mvbuf[idx], mvn);     \
+                mvbuf[idx][1] <<= 1;            \
+                mvn = mvbuf[idx];               \
+            }                                   \
+        }                                       \
+    }
 
-    tprintf(h->s.avctx, "pred_pskip: (%d) (%d) at %2d %2d\n", top_ref, left_ref, h->s.mb_x, h->s.mb_y);
+static av_always_inline void pred_pskip_motion(H264Context *const h)
+{
+    DECLARE_ALIGNED(4, static const int16_t, zeromv)[2] = { 0 };
+    DECLARE_ALIGNED(4, int16_t, mvbuf)[3][2];
+    MpegEncContext *const s = &h->s;
+    int8_t *ref     = s->current_picture.f.ref_index[0];
+    int16_t(*mv)[2] = s->current_picture.f.motion_val[0];
+    int top_ref, left_ref, diagonal_ref, match_count, mx, my;
+    const int16_t *A, *B, *C;
+    int b_stride = h->b_stride;
+
+    fill_rectangle(&h->ref_cache[0][scan8[0]], 4, 4, 8, 0, 1);
+
+    /* To avoid doing an entire fill_decode_caches, we inline the relevant
+     * parts here.
+     * FIXME: this is a partial duplicate of the logic in fill_decode_caches,
+     * but it's faster this way.  Is there a way to avoid this duplication?
+     */
+    if (USES_LIST(h->left_type[LTOP], 0)) {
+        left_ref = ref[4 * h->left_mb_xy[LTOP] + 1 + (h->left_block[0] & ~1)];
+        A = mv[h->mb2b_xy[h->left_mb_xy[LTOP]] + 3 + b_stride * h->left_block[0]];
+        FIX_MV_MBAFF(h->left_type[LTOP], left_ref, A, 0);
+        if (!(left_ref | AV_RN32A(A)))
+            goto zeromv;
+    } else if (h->left_type[LTOP]) {
+        left_ref = LIST_NOT_USED;
+        A        = zeromv;
+    } else {
+        goto zeromv;
+    }
 
-    if(top_ref == PART_NOT_AVAILABLE || left_ref == PART_NOT_AVAILABLE
-       || !( top_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 8 ]))
-       || !(left_ref | AV_RN32A(h->mv_cache[0][ scan8[0] - 1 ]))){
+    if (USES_LIST(h->top_type, 0)) {
+        top_ref = ref[4 * h->top_mb_xy + 2];
+        B       = mv[h->mb2b_xy[h->top_mb_xy] + 3 * b_stride];
+        FIX_MV_MBAFF(h->top_type, top_ref, B, 1);
+        if (!(top_ref | AV_RN32A(B)))
+            goto zeromv;
+    } else if (h->top_type) {
+        top_ref = LIST_NOT_USED;
+        B       = zeromv;
+    } else {
+        goto zeromv;
+    }
 
-        *mx = *my = 0;
-        return;
+    tprintf(h->s.avctx, "pred_pskip: (%d) (%d) at %2d %2d\n",
+            top_ref, left_ref, h->s.mb_x, h->s.mb_y);
+
+    if (USES_LIST(h->topright_type, 0)) {
+        diagonal_ref = ref[4 * h->topright_mb_xy + 2];
+        C = mv[h->mb2b_xy[h->topright_mb_xy] + 3 * b_stride];
+        FIX_MV_MBAFF(h->topright_type, diagonal_ref, C, 2);
+    } else if (h->topright_type) {
+        diagonal_ref = LIST_NOT_USED;
+        C = zeromv;
+    } else {
+        if (USES_LIST(h->topleft_type, 0)) {
+            diagonal_ref = ref[4 * h->topleft_mb_xy + 1 +
+                               (h->topleft_partition & 2)];
+            C = mv[h->mb2b_xy[h->topleft_mb_xy] + 3 + b_stride +
+                   (h->topleft_partition & 2 * b_stride)];
+            FIX_MV_MBAFF(h->topleft_type, diagonal_ref, C, 2);
+        } else if (h->topleft_type) {
+            diagonal_ref = LIST_NOT_USED;
+            C            = zeromv;
+        } else {
+            diagonal_ref = PART_NOT_AVAILABLE;
+            C            = zeromv;
+        }
     }
 
-    pred_motion(h, 0, 4, 0, 0, mx, my);
+    match_count = !diagonal_ref + !top_ref + !left_ref;
+    tprintf(h->s.avctx, "pred_pskip_motion match_count=%d\n", match_count);
+    if (match_count > 1) {
+        mx = mid_pred(A[0], B[0], C[0]);
+        my = mid_pred(A[1], B[1], C[1]);
+    } else if (match_count == 1) {
+        if (!left_ref) {
+            mx = A[0];
+            my = A[1];
+        } else if (!top_ref) {
+            mx = B[0];
+            my = B[1];
+        } else {
+            mx = C[0];
+            my = C[1];
+        }
+    } else {
+        mx = mid_pred(A[0], B[0], C[0]);
+        my = mid_pred(A[1], B[1], C[1]);
+    }
+
+    fill_rectangle(h->mv_cache[0][scan8[0]], 4, 4, 8, pack16to32(mx, my), 4);
+    return;
 
+zeromv:
+    fill_rectangle(h->mv_cache[0][scan8[0]], 4, 4, 8, 0, 4);
     return;
 }
 
+static void fill_decode_neighbors(H264Context *h, int mb_type)
+{
+    MpegEncContext *const s = &h->s;
+    const int mb_xy = h->mb_xy;
+    int topleft_xy, top_xy, topright_xy, left_xy[LEFT_MBS];
+    static const uint8_t left_block_options[4][32] = {
+        { 0, 1, 2, 3, 7, 10, 8, 11, 3 + 0 * 4, 3 + 1 * 4, 3 + 2 * 4, 3 + 3 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 5 * 4, 1 + 9 * 4 },
+        { 2, 2, 3, 3, 8, 11, 8, 11, 3 + 2 * 4, 3 + 2 * 4, 3 + 3 * 4, 3 + 3 * 4, 1 + 5 * 4, 1 + 9 * 4, 1 + 5 * 4, 1 + 9 * 4 },
+        { 0, 0, 1, 1, 7, 10, 7, 10, 3 + 0 * 4, 3 + 0 * 4, 3 + 1 * 4, 3 + 1 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 },
+        { 0, 2, 0, 2, 7, 10, 7, 10, 3 + 0 * 4, 3 + 2 * 4, 3 + 0 * 4, 3 + 2 * 4, 1 + 4 * 4, 1 + 8 * 4, 1 + 4 * 4, 1 + 8 * 4 }
+    };
+
+    h->topleft_partition = -1;
+
+    top_xy = mb_xy - (s->mb_stride << MB_FIELD);
+
+    /* Wow, what a mess, why didn't they simplify the interlacing & intra
+     * stuff, I can't imagine that these complex rules are worth it. */
+
+    topleft_xy    = top_xy - 1;
+    topright_xy   = top_xy + 1;
+    left_xy[LBOT] = left_xy[LTOP] = mb_xy - 1;
+    h->left_block = left_block_options[0];
+    if (FRAME_MBAFF) {
+        const int left_mb_field_flag = IS_INTERLACED(s->current_picture.f.mb_type[mb_xy - 1]);
+        const int curr_mb_field_flag = IS_INTERLACED(mb_type);
+        if (s->mb_y & 1) {
+            if (left_mb_field_flag != curr_mb_field_flag) {
+                left_xy[LBOT] = left_xy[LTOP] = mb_xy - s->mb_stride - 1;
+                if (curr_mb_field_flag) {
+                    left_xy[LBOT] += s->mb_stride;
+                    h->left_block  = left_block_options[3];
+                } else {
+                    topleft_xy += s->mb_stride;
+                    /* take top left mv from the middle of the mb, as opposed
+                     * to all other modes which use the bottom right partition */
+                    h->topleft_partition = 0;
+                    h->left_block        = left_block_options[1];
+                }
+            }
+        } else {
+            if (curr_mb_field_flag) {
+                topleft_xy  += s->mb_stride & (((s->current_picture.f.mb_type[top_xy - 1] >> 7) & 1) - 1);
+                topright_xy += s->mb_stride & (((s->current_picture.f.mb_type[top_xy + 1] >> 7) & 1) - 1);
+                top_xy      += s->mb_stride & (((s->current_picture.f.mb_type[top_xy]     >> 7) & 1) - 1);
+            }
+            if (left_mb_field_flag != curr_mb_field_flag) {
+                if (curr_mb_field_flag) {
+                    left_xy[LBOT] += s->mb_stride;
+                    h->left_block  = left_block_options[3];
+                } else {
+                    h->left_block = left_block_options[2];
+                }
+            }
+        }
+    }
+
+    h->topleft_mb_xy    = topleft_xy;
+    h->top_mb_xy        = top_xy;
+    h->topright_mb_xy   = topright_xy;
+    h->left_mb_xy[LTOP] = left_xy[LTOP];
+    h->left_mb_xy[LBOT] = left_xy[LBOT];
+    //FIXME do we need all in the context?
+
+    h->topleft_type    = s->current_picture.f.mb_type[topleft_xy];
+    h->top_type        = s->current_picture.f.mb_type[top_xy];
+    h->topright_type   = s->current_picture.f.mb_type[topright_xy];
+    h->left_type[LTOP] = s->current_picture.f.mb_type[left_xy[LTOP]];
+    h->left_type[LBOT] = s->current_picture.f.mb_type[left_xy[LBOT]];
+
+    if (FMO) {
+        if (h->slice_table[topleft_xy] != h->slice_num)
+            h->topleft_type = 0;
+        if (h->slice_table[top_xy] != h->slice_num)
+            h->top_type = 0;
+        if (h->slice_table[left_xy[LTOP]] != h->slice_num)
+            h->left_type[LTOP] = h->left_type[LBOT] = 0;
+    } else {
+        if (h->slice_table[topleft_xy] != h->slice_num) {
+            h->topleft_type = 0;
+            if (h->slice_table[top_xy] != h->slice_num)
+                h->top_type = 0;
+            if (h->slice_table[left_xy[LTOP]] != h->slice_num)
+                h->left_type[LTOP] = h->left_type[LBOT] = 0;
+        }
+    }
+    if (h->slice_table[topright_xy] != h->slice_num)
+        h->topright_type = 0;
+}
+
+static void fill_decode_caches(H264Context *h, int mb_type)
+{
+    MpegEncContext *const s = &h->s;
+    int topleft_xy, top_xy, topright_xy, left_xy[LEFT_MBS];
+    int topleft_type, top_type, topright_type, left_type[LEFT_MBS];
+    const uint8_t *left_block = h->left_block;
+    int i;
+    uint8_t *nnz;
+    uint8_t *nnz_cache;
+
+    topleft_xy      = h->topleft_mb_xy;
+    top_xy          = h->top_mb_xy;
+    topright_xy     = h->topright_mb_xy;
+    left_xy[LTOP]   = h->left_mb_xy[LTOP];
+    left_xy[LBOT]   = h->left_mb_xy[LBOT];
+    topleft_type    = h->topleft_type;
+    top_type        = h->top_type;
+    topright_type   = h->topright_type;
+    left_type[LTOP] = h->left_type[LTOP];
+    left_type[LBOT] = h->left_type[LBOT];
+
+    if (!IS_SKIP(mb_type)) {
+        if (IS_INTRA(mb_type)) {
+            int type_mask = h->pps.constrained_intra_pred ? IS_INTRA(-1) : -1;
+            h->topleft_samples_available      =
+                h->top_samples_available      =
+                    h->left_samples_available = 0xFFFF;
+            h->topright_samples_available     = 0xEEEA;
+
+            if (!(top_type & type_mask)) {
+                h->topleft_samples_available  = 0xB3FF;
+                h->top_samples_available      = 0x33FF;
+                h->topright_samples_available = 0x26EA;
+            }
+            if (IS_INTERLACED(mb_type) != IS_INTERLACED(left_type[LTOP])) {
+                if (IS_INTERLACED(mb_type)) {
+                    if (!(left_type[LTOP] & type_mask)) {
+                        h->topleft_samples_available &= 0xDFFF;
+                        h->left_samples_available    &= 0x5FFF;
+                    }
+                    if (!(left_type[LBOT] & type_mask)) {
+                        h->topleft_samples_available &= 0xFF5F;
+                        h->left_samples_available    &= 0xFF5F;
+                    }
+                } else {
+                    int left_typei = s->current_picture.f.mb_type[left_xy[LTOP] + s->mb_stride];
+
+                    assert(left_xy[LTOP] == left_xy[LBOT]);
+                    if (!((left_typei & type_mask) && (left_type[LTOP] & type_mask))) {
+                        h->topleft_samples_available &= 0xDF5F;
+                        h->left_samples_available    &= 0x5F5F;
+                    }
+                }
+            } else {
+                if (!(left_type[LTOP] & type_mask)) {
+                    h->topleft_samples_available &= 0xDF5F;
+                    h->left_samples_available    &= 0x5F5F;
+                }
+            }
+
+            if (!(topleft_type & type_mask))
+                h->topleft_samples_available &= 0x7FFF;
+
+            if (!(topright_type & type_mask))
+                h->topright_samples_available &= 0xFBFF;
+
+            if (IS_INTRA4x4(mb_type)) {
+                if (IS_INTRA4x4(top_type)) {
+                    AV_COPY32(h->intra4x4_pred_mode_cache + 4 + 8 * 0, h->intra4x4_pred_mode + h->mb2br_xy[top_xy]);
+                } else {
+                    h->intra4x4_pred_mode_cache[4 + 8 * 0] =
+                    h->intra4x4_pred_mode_cache[5 + 8 * 0] =
+                    h->intra4x4_pred_mode_cache[6 + 8 * 0] =
+                    h->intra4x4_pred_mode_cache[7 + 8 * 0] = 2 - 3 * !(top_type & type_mask);
+                }
+                for (i = 0; i < 2; i++) {
+                    if (IS_INTRA4x4(left_type[LEFT(i)])) {
+                        int8_t *mode = h->intra4x4_pred_mode + h->mb2br_xy[left_xy[LEFT(i)]];
+                        h->intra4x4_pred_mode_cache[3 + 8 * 1 + 2 * 8 * i] = mode[6 - left_block[0 + 2 * i]];
+                        h->intra4x4_pred_mode_cache[3 + 8 * 2 + 2 * 8 * i] = mode[6 - left_block[1 + 2 * i]];
+                    } else {
+                        h->intra4x4_pred_mode_cache[3 + 8 * 1 + 2 * 8 * i] =
+                        h->intra4x4_pred_mode_cache[3 + 8 * 2 + 2 * 8 * i] = 2 - 3 * !(left_type[LEFT(i)] & type_mask);
+                    }
+                }
+            }
+        }
+
+        /*
+         * 0 . T T. T T T T
+         * 1 L . .L . . . .
+         * 2 L . .L . . . .
+         * 3 . T TL . . . .
+         * 4 L . .L . . . .
+         * 5 L . .. . . . .
+         */
+        /* FIXME: constraint_intra_pred & partitioning & nnz
+         * (let us hope this is just a typo in the spec) */
+        nnz_cache = h->non_zero_count_cache;
+        if (top_type) {
+            nnz = h->non_zero_count[top_xy];
+            AV_COPY32(&nnz_cache[4 + 8 * 0], &nnz[4 * 3]);
+            if (!s->chroma_y_shift) {
+                AV_COPY32(&nnz_cache[4 + 8 *  5], &nnz[4 *  7]);
+                AV_COPY32(&nnz_cache[4 + 8 * 10], &nnz[4 * 11]);
+            } else {
+                AV_COPY32(&nnz_cache[4 + 8 *  5], &nnz[4 * 5]);
+                AV_COPY32(&nnz_cache[4 + 8 * 10], &nnz[4 * 9]);
+            }
+        } else {
+            uint32_t top_empty = CABAC && !IS_INTRA(mb_type) ? 0 : 0x40404040;
+            AV_WN32A(&nnz_cache[4 + 8 *  0], top_empty);
+            AV_WN32A(&nnz_cache[4 + 8 *  5], top_empty);
+            AV_WN32A(&nnz_cache[4 + 8 * 10], top_empty);
+        }
+
+        for (i = 0; i < 2; i++) {
+            if (left_type[LEFT(i)]) {
+                nnz = h->non_zero_count[left_xy[LEFT(i)]];
+                nnz_cache[3 + 8 * 1 + 2 * 8 * i] = nnz[left_block[8 + 0 + 2 * i]];
+                nnz_cache[3 + 8 * 2 + 2 * 8 * i] = nnz[left_block[8 + 1 + 2 * i]];
+                if (CHROMA444) {
+                    nnz_cache[3 + 8 *  6 + 2 * 8 * i] = nnz[left_block[8 + 0 + 2 * i] + 4 * 4];
+                    nnz_cache[3 + 8 *  7 + 2 * 8 * i] = nnz[left_block[8 + 1 + 2 * i] + 4 * 4];
+                    nnz_cache[3 + 8 * 11 + 2 * 8 * i] = nnz[left_block[8 + 0 + 2 * i] + 8 * 4];
+                    nnz_cache[3 + 8 * 12 + 2 * 8 * i] = nnz[left_block[8 + 1 + 2 * i] + 8 * 4];
+                } else if (CHROMA422) {
+                    nnz_cache[3 + 8 *  6 + 2 * 8 * i] = nnz[left_block[8 + 0 + 2 * i] - 2 + 4 * 4];
+                    nnz_cache[3 + 8 *  7 + 2 * 8 * i] = nnz[left_block[8 + 1 + 2 * i] - 2 + 4 * 4];
+                    nnz_cache[3 + 8 * 11 + 2 * 8 * i] = nnz[left_block[8 + 0 + 2 * i] - 2 + 8 * 4];
+                    nnz_cache[3 + 8 * 12 + 2 * 8 * i] = nnz[left_block[8 + 1 + 2 * i] - 2 + 8 * 4];
+                } else {
+                    nnz_cache[3 + 8 *  6 + 8 * i] = nnz[left_block[8 + 4 + 2 * i]];
+                    nnz_cache[3 + 8 * 11 + 8 * i] = nnz[left_block[8 + 5 + 2 * i]];
+                }
+            } else {
+                nnz_cache[3 + 8 *  1 + 2 * 8 * i] =
+                nnz_cache[3 + 8 *  2 + 2 * 8 * i] =
+                nnz_cache[3 + 8 *  6 + 2 * 8 * i] =
+                nnz_cache[3 + 8 *  7 + 2 * 8 * i] =
+                nnz_cache[3 + 8 * 11 + 2 * 8 * i] =
+                nnz_cache[3 + 8 * 12 + 2 * 8 * i] = CABAC && !IS_INTRA(mb_type) ? 0 : 64;
+            }
+        }
+
+        if (CABAC) {
+            // top_cbp
+            if (top_type)
+                h->top_cbp = h->cbp_table[top_xy];
+            else
+                h->top_cbp = IS_INTRA(mb_type) ? 0x7CF : 0x00F;
+            // left_cbp
+            if (left_type[LTOP]) {
+                h->left_cbp =   (h->cbp_table[left_xy[LTOP]] & 0x7F0) |
+                               ((h->cbp_table[left_xy[LTOP]] >> (left_block[0] & (~1))) & 2) |
+                              (((h->cbp_table[left_xy[LBOT]] >> (left_block[2] & (~1))) & 2) << 2);
+            } else {
+                h->left_cbp = IS_INTRA(mb_type) ? 0x7CF : 0x00F;
+            }
+        }
+    }
+
+    if (IS_INTER(mb_type) || (IS_DIRECT(mb_type) && h->direct_spatial_mv_pred)) {
+        int list;
+        int b_stride = h->b_stride;
+        for (list = 0; list < h->list_count; list++) {
+            int8_t *ref_cache = &h->ref_cache[list][scan8[0]];
+            int8_t *ref       = s->current_picture.f.ref_index[list];
+            int16_t(*mv_cache)[2] = &h->mv_cache[list][scan8[0]];
+            int16_t(*mv)[2]       = s->current_picture.f.motion_val[list];
+            if (!USES_LIST(mb_type, list))
+                continue;
+            assert(!(IS_DIRECT(mb_type) && !h->direct_spatial_mv_pred));
+
+            if (USES_LIST(top_type, list)) {
+                const int b_xy = h->mb2b_xy[top_xy] + 3 * b_stride;
+                AV_COPY128(mv_cache[0 - 1 * 8], mv[b_xy + 0]);
+                ref_cache[0 - 1 * 8] =
+                ref_cache[1 - 1 * 8] = ref[4 * top_xy + 2];
+                ref_cache[2 - 1 * 8] =
+                ref_cache[3 - 1 * 8] = ref[4 * top_xy + 3];
+            } else {
+                AV_ZERO128(mv_cache[0 - 1 * 8]);
+                AV_WN32A(&ref_cache[0 - 1 * 8],
+                         ((top_type ? LIST_NOT_USED : PART_NOT_AVAILABLE) & 0xFF) * 0x01010101u);
+            }
+
+            if (mb_type & (MB_TYPE_16x8 | MB_TYPE_8x8)) {
+                for (i = 0; i < 2; i++) {
+                    int cache_idx = -1 + i * 2 * 8;
+                    if (USES_LIST(left_type[LEFT(i)], list)) {
+                        const int b_xy  = h->mb2b_xy[left_xy[LEFT(i)]] + 3;
+                        const int b8_xy = 4 * left_xy[LEFT(i)] + 1;
+                        AV_COPY32(mv_cache[cache_idx],
+                                  mv[b_xy + b_stride * left_block[0 + i * 2]]);
+                        AV_COPY32(mv_cache[cache_idx + 8],
+                                  mv[b_xy + b_stride * left_block[1 + i * 2]]);
+                        ref_cache[cache_idx]     = ref[b8_xy + (left_block[0 + i * 2] & ~1)];
+                        ref_cache[cache_idx + 8] = ref[b8_xy + (left_block[1 + i * 2] & ~1)];
+                    } else {
+                        AV_ZERO32(mv_cache[cache_idx]);
+                        AV_ZERO32(mv_cache[cache_idx + 8]);
+                        ref_cache[cache_idx]     =
+                        ref_cache[cache_idx + 8] = (left_type[LEFT(i)]) ? LIST_NOT_USED
+                                                                        : PART_NOT_AVAILABLE;
+                    }
+                }
+            } else {
+                if (USES_LIST(left_type[LTOP], list)) {
+                    const int b_xy  = h->mb2b_xy[left_xy[LTOP]] + 3;
+                    const int b8_xy = 4 * left_xy[LTOP] + 1;
+                    AV_COPY32(mv_cache[-1], mv[b_xy + b_stride * left_block[0]]);
+                    ref_cache[-1] = ref[b8_xy + (left_block[0] & ~1)];
+                } else {
+                    AV_ZERO32(mv_cache[-1]);
+                    ref_cache[-1] = left_type[LTOP] ? LIST_NOT_USED
+                                                    : PART_NOT_AVAILABLE;
+                }
+            }
+
+            if (USES_LIST(topright_type, list)) {
+                const int b_xy = h->mb2b_xy[topright_xy] + 3 * b_stride;
+                AV_COPY32(mv_cache[4 - 1 * 8], mv[b_xy]);
+                ref_cache[4 - 1 * 8] = ref[4 * topright_xy + 2];
+            } else {
+                AV_ZERO32(mv_cache[4 - 1 * 8]);
+                ref_cache[4 - 1 * 8] = topright_type ? LIST_NOT_USED
+                                                     : PART_NOT_AVAILABLE;
+            }
+            if (ref_cache[4 - 1 * 8] < 0) {
+                if (USES_LIST(topleft_type, list)) {
+                    const int b_xy  = h->mb2b_xy[topleft_xy] + 3 + b_stride +
+                                      (h->topleft_partition & 2 * b_stride);
+                    const int b8_xy = 4 * topleft_xy + 1 + (h->topleft_partition & 2);
+                    AV_COPY32(mv_cache[-1 - 1 * 8], mv[b_xy]);
+                    ref_cache[-1 - 1 * 8] = ref[b8_xy];
+                } else {
+                    AV_ZERO32(mv_cache[-1 - 1 * 8]);
+                    ref_cache[-1 - 1 * 8] = topleft_type ? LIST_NOT_USED
+                                                         : PART_NOT_AVAILABLE;
+                }
+            }
+
+            if ((mb_type & (MB_TYPE_SKIP | MB_TYPE_DIRECT2)) && !FRAME_MBAFF)
+                continue;
+
+            if (!(mb_type & (MB_TYPE_SKIP | MB_TYPE_DIRECT2))) {
+                uint8_t(*mvd_cache)[2]   = &h->mvd_cache[list][scan8[0]];
+                uint8_t(*mvd)[2]         = h->mvd_table[list];
+                ref_cache[2 + 8 * 0] =
+                ref_cache[2 + 8 * 2] = PART_NOT_AVAILABLE;
+                AV_ZERO32(mv_cache[2 + 8 * 0]);
+                AV_ZERO32(mv_cache[2 + 8 * 2]);
+
+                if (CABAC) {
+                    if (USES_LIST(top_type, list)) {
+                        const int b_xy = h->mb2br_xy[top_xy];
+                        AV_COPY64(mvd_cache[0 - 1 * 8], mvd[b_xy + 0]);
+                    } else {
+                        AV_ZERO64(mvd_cache[0 - 1 * 8]);
+                    }
+                    if (USES_LIST(left_type[LTOP], list)) {
+                        const int b_xy = h->mb2br_xy[left_xy[LTOP]] + 6;
+                        AV_COPY16(mvd_cache[-1 + 0 * 8], mvd[b_xy - left_block[0]]);
+                        AV_COPY16(mvd_cache[-1 + 1 * 8], mvd[b_xy - left_block[1]]);
+                    } else {
+                        AV_ZERO16(mvd_cache[-1 + 0 * 8]);
+                        AV_ZERO16(mvd_cache[-1 + 1 * 8]);
+                    }
+                    if (USES_LIST(left_type[LBOT], list)) {
+                        const int b_xy = h->mb2br_xy[left_xy[LBOT]] + 6;
+                        AV_COPY16(mvd_cache[-1 + 2 * 8], mvd[b_xy - left_block[2]]);
+                        AV_COPY16(mvd_cache[-1 + 3 * 8], mvd[b_xy - left_block[3]]);
+                    } else {
+                        AV_ZERO16(mvd_cache[-1 + 2 * 8]);
+                        AV_ZERO16(mvd_cache[-1 + 3 * 8]);
+                    }
+                    AV_ZERO16(mvd_cache[2 + 8 * 0]);
+                    AV_ZERO16(mvd_cache[2 + 8 * 2]);
+                    if (h->slice_type_nos == AV_PICTURE_TYPE_B) {
+                        uint8_t *direct_cache = &h->direct_cache[scan8[0]];
+                        uint8_t *direct_table = h->direct_table;
+                        fill_rectangle(direct_cache, 4, 4, 8, MB_TYPE_16x16 >> 1, 1);
+
+                        if (IS_DIRECT(top_type)) {
+                            AV_WN32A(&direct_cache[-1 * 8],
+                                     0x01010101u * (MB_TYPE_DIRECT2 >> 1));
+                        } else if (IS_8X8(top_type)) {
+                            int b8_xy = 4 * top_xy;
+                            direct_cache[0 - 1 * 8] = direct_table[b8_xy + 2];
+                            direct_cache[2 - 1 * 8] = direct_table[b8_xy + 3];
+                        } else {
+                            AV_WN32A(&direct_cache[-1 * 8],
+                                     0x01010101 * (MB_TYPE_16x16 >> 1));
+                        }
+
+                        if (IS_DIRECT(left_type[LTOP]))
+                            direct_cache[-1 + 0 * 8] = MB_TYPE_DIRECT2 >> 1;
+                        else if (IS_8X8(left_type[LTOP]))
+                            direct_cache[-1 + 0 * 8] = direct_table[4 * left_xy[LTOP] + 1 + (left_block[0] & ~1)];
+                        else
+                            direct_cache[-1 + 0 * 8] = MB_TYPE_16x16 >> 1;
+
+                        if (IS_DIRECT(left_type[LBOT]))
+                            direct_cache[-1 + 2 * 8] = MB_TYPE_DIRECT2 >> 1;
+                        else if (IS_8X8(left_type[LBOT]))
+                            direct_cache[-1 + 2 * 8] = direct_table[4 * left_xy[LBOT] + 1 + (left_block[2] & ~1)];
+                        else
+                            direct_cache[-1 + 2 * 8] = MB_TYPE_16x16 >> 1;
+                    }
+                }
+            }
+
+#define MAP_MVS                                                         \
+    MAP_F2F(scan8[0] - 1 - 1 * 8, topleft_type)                         \
+    MAP_F2F(scan8[0] + 0 - 1 * 8, top_type)                             \
+    MAP_F2F(scan8[0] + 1 - 1 * 8, top_type)                             \
+    MAP_F2F(scan8[0] + 2 - 1 * 8, top_type)                             \
+    MAP_F2F(scan8[0] + 3 - 1 * 8, top_type)                             \
+    MAP_F2F(scan8[0] + 4 - 1 * 8, topright_type)                        \
+    MAP_F2F(scan8[0] - 1 + 0 * 8, left_type[LTOP])                      \
+    MAP_F2F(scan8[0] - 1 + 1 * 8, left_type[LTOP])                      \
+    MAP_F2F(scan8[0] - 1 + 2 * 8, left_type[LBOT])                      \
+    MAP_F2F(scan8[0] - 1 + 3 * 8, left_type[LBOT])
+
+            if (FRAME_MBAFF) {
+                if (MB_FIELD) {
+
+#define MAP_F2F(idx, mb_type)                                           \
+    if (!IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0) {      \
+        h->ref_cache[list][idx]    <<= 1;                               \
+        h->mv_cache[list][idx][1]   /= 2;                               \
+        h->mvd_cache[list][idx][1] >>= 1;                               \
+    }
+
+                    MAP_MVS
+                } else {
+
+#undef MAP_F2F
+#define MAP_F2F(idx, mb_type)                                           \
+    if (IS_INTERLACED(mb_type) && h->ref_cache[list][idx] >= 0) {       \
+        h->ref_cache[list][idx]    >>= 1;                               \
+        h->mv_cache[list][idx][1]  <<= 1;                               \
+        h->mvd_cache[list][idx][1] <<= 1;                               \
+    }
+
+                    MAP_MVS
+#undef MAP_F2F
+                }
+            }
+        }
+    }
+
+    h->neighbor_transform_size = !!IS_8x8DCT(top_type) + !!IS_8x8DCT(left_type[LTOP]);
+}
+
+/**
+ * decodes a P_SKIP or B_SKIP macroblock
+ */
+static void av_unused decode_mb_skip(H264Context *h)
+{
+    MpegEncContext *const s = &h->s;
+    const int mb_xy = h->mb_xy;
+    int mb_type     = 0;
+
+    memset(h->non_zero_count[mb_xy], 0, 48);
+
+    if (MB_FIELD)
+        mb_type |= MB_TYPE_INTERLACED;
+
+    if (h->slice_type_nos == AV_PICTURE_TYPE_B) {
+        // just for fill_caches. pred_direct_motion will set the real mb_type
+        mb_type |= MB_TYPE_L0L1 | MB_TYPE_DIRECT2 | MB_TYPE_SKIP;
+        if (h->direct_spatial_mv_pred) {
+            fill_decode_neighbors(h, mb_type);
+            fill_decode_caches(h, mb_type); //FIXME check what is needed and what not ...
+        }
+        ff_h264_pred_direct_motion(h, &mb_type);
+        mb_type |= MB_TYPE_SKIP;
+    } else {
+        mb_type |= MB_TYPE_16x16 | MB_TYPE_P0L0 | MB_TYPE_P1L0 | MB_TYPE_SKIP;
+
+        fill_decode_neighbors(h, mb_type);
+        pred_pskip_motion(h);
+    }
+
+    write_back_motion(h, mb_type);
+    s->current_picture.f.mb_type[mb_xy]      = mb_type;
+    s->current_picture.f.qscale_table[mb_xy] = s->qscale;
+    h->slice_table[mb_xy]                    = h->slice_num;
+    h->prev_mb_skipped                       = 1;
+}
+
 #endif /* AVCODEC_H264_MVPRED_H */