vc1: make overlap filter for I-frames bit-exact.

libavcodec/vc1.h

@@ -317,6 +317,8 @@ typedef struct VC1Context{
     int bi_type;
     int x8_type;
 
+    DCTELEM (*block)[6][64];
+    int n_allocated_blks, cur_blk_idx, left_blk_idx, topleft_blk_idx, top_blk_idx;
     uint32_t *cbp_base, *cbp;
     uint8_t *is_intra_base, *is_intra;
     int16_t (*luma_mv_base)[2], (*luma_mv)[2];

libavcodec/vc1dsp.c

@@ -78,6 +78,58 @@ static void vc1_h_overlap_c(uint8_t* src, int stride)
     }
 }
 
+static void vc1_v_s_overlap_c(DCTELEM *top,  DCTELEM *bottom)
+{
+    int i;
+    int a, b, c, d;
+    int d1, d2;
+    int rnd1 = 4, rnd2 = 3;
+    for(i = 0; i < 8; i++) {
+        a = top[48];
+        b = top[56];
+        c = bottom[0];
+        d = bottom[8];
+        d1 = a - d;
+        d2 = a - d + b - c;
+
+        top[48]   = ((a << 3) - d1 + rnd1) >> 3;
+        top[56]   = ((b << 3) - d2 + rnd2) >> 3;
+        bottom[0] = ((c << 3) + d2 + rnd1) >> 3;
+        bottom[8] = ((d << 3) + d1 + rnd2) >> 3;
+
+        bottom++;
+        top++;
+        rnd2 = 7 - rnd2;
+        rnd1 = 7 - rnd1;
+    }
+}
+
+static void vc1_h_s_overlap_c(DCTELEM *left, DCTELEM *right)
+{
+    int i;
+    int a, b, c, d;
+    int d1, d2;
+    int rnd1 = 4, rnd2 = 3;
+    for(i = 0; i < 8; i++) {
+        a = left[6];
+        b = left[7];
+        c = right[0];
+        d = right[1];
+        d1 = a - d;
+        d2 = a - d + b - c;
+
+        left[6]  = ((a << 3) - d1 + rnd1) >> 3;
+        left[7]  = ((b << 3) - d2 + rnd2) >> 3;
+        right[0] = ((c << 3) + d2 + rnd1) >> 3;
+        right[1] = ((d << 3) + d1 + rnd2) >> 3;
+
+        right += 8;
+        left += 8;
+        rnd2 = 7 - rnd2;
+        rnd1 = 7 - rnd1;
+    }
+}
+
 /**
  * VC-1 in-loop deblocking filter for one line
  * @param src source block type
@@ -672,6 +724,8 @@ av_cold void ff_vc1dsp_init(VC1DSPContext* dsp) {
     dsp->vc1_inv_trans_4x4_dc = vc1_inv_trans_4x4_dc_c;
     dsp->vc1_h_overlap = vc1_h_overlap_c;
     dsp->vc1_v_overlap = vc1_v_overlap_c;
+    dsp->vc1_h_s_overlap = vc1_h_s_overlap_c;
+    dsp->vc1_v_s_overlap = vc1_v_s_overlap_c;
     dsp->vc1_v_loop_filter4 = vc1_v_loop_filter4_c;
     dsp->vc1_h_loop_filter4 = vc1_h_loop_filter4_c;
     dsp->vc1_v_loop_filter8 = vc1_v_loop_filter8_c;

libavcodec/vc1dsp.h

@@ -40,8 +40,10 @@ typedef struct VC1DSPContext {
     void (*vc1_inv_trans_8x4_dc)(uint8_t *dest, int line_size, DCTELEM *block);
     void (*vc1_inv_trans_4x8_dc)(uint8_t *dest, int line_size, DCTELEM *block);
     void (*vc1_inv_trans_4x4_dc)(uint8_t *dest, int line_size, DCTELEM *block);
-    void (*vc1_v_overlap)(uint8_t* src, int stride);
-    void (*vc1_h_overlap)(uint8_t* src, int stride);
+    void (*vc1_v_overlap)(uint8_t *src, int stride);
+    void (*vc1_h_overlap)(uint8_t *src, int stride);
+    void (*vc1_v_s_overlap)(DCTELEM *top,  DCTELEM *bottom);
+    void (*vc1_h_s_overlap)(DCTELEM *left, DCTELEM *right);
     void (*vc1_v_loop_filter4)(uint8_t *src, int stride, int pq);
     void (*vc1_h_loop_filter4)(uint8_t *src, int stride, int pq);
     void (*vc1_v_loop_filter8)(uint8_t *src, int stride, int pq);

tests/ref/fate/vc1

-0, 0, 38016, 0xf4715db5
-0, 3600, 38016, 0xf4715db5
-0, 7200, 38016, 0xf4715db5
-0, 10800, 38016, 0xf46af0e1
-0, 14400, 38016, 0x9c1c2cf1
-0, 18000, 38016, 0xff12d87f
-0, 21600, 38016, 0x7408432b
-0, 25200, 38016, 0x7408432b
-0, 28800, 38016, 0x8d11479a
-0, 32400, 38016, 0x8d11479a
-0, 36000, 38016, 0xc4a121ab
-0, 39600, 38016, 0xc4a121ab
-0, 43200, 38016, 0xc4a121ab
-0, 46800, 38016, 0xc4a121ab
-0, 50400, 38016, 0xc4a121ab
+0, 0, 38016, 0xa6f15db5
+0, 3600, 38016, 0xa6f15db5
+0, 7200, 38016, 0xa6f15db5
+0, 10800, 38016, 0x5c4ef0e7
+0, 14400, 38016, 0x53a42d1d
+0, 18000, 38016, 0x68f7d89e
+0, 21600, 38016, 0xc15f4368
+0, 25200, 38016, 0xc15f4368
+0, 28800, 38016, 0xd1bd47a8
+0, 32400, 38016, 0xd1bd47a8
+0, 36000, 38016, 0xe1e821ca
+0, 39600, 38016, 0xe1e821ca
+0, 43200, 38016, 0xe1e821ca
+0, 46800, 38016, 0xe1e821ca
+0, 50400, 38016, 0xe1e821ca