[mip] Fix issue with invalid MIP modes written into cabac. Fix Mip mode cost estimation. Implement function to derive mip flag context id. Fix some asserts. Replace floor log 2 implementation with existing kvz math function.

src/encode_coding_tree.c

@@ -873,28 +873,13 @@ static void encode_intra_coding_unit(encoder_state_t * const state,
   }
 
   if (mip_flag) {
-    assert(mip_mode >= 0 && mip_mode < 16 && "MIP mode must be between [0, 15]");
+    assert(mip_mode >= 0 && mip_mode < num_mip_modes && "Invalid MIP mode.");
   }
 
   if (cur_cu->type == CU_INTRA && !cur_cu->bdpcmMode && enable_mip) {
-    // Derive mip flag context id
-    uint8_t ctx_id = 0;
     const int cu_width = LCU_WIDTH >> depth;
     const int cu_height = cu_width; // TODO: height for non-square blocks
-    const int pu_x = PU_GET_X(cur_cu->part_size, cu_width, x, 0);
+    uint8_t ctx_id = kvz_get_mip_flag_context(x, y, cu_width, cu_height, NULL, frame->cu_array);
-    const int pu_y = PU_GET_Y(cur_cu->part_size, cu_height, y, 0);
-
-    if (pu_x > 0) {
-      assert(pu_x >> 2 > 0);
-      // Get mip flag from left PU
-      ctx_id = kvz_cu_array_at_const(frame->cu_array, pu_x - 1, pu_y)->intra.mip_flag ? 1 : 0;
-    }
-    if (pu_y % LCU_WIDTH > 0 && pu_y > 0) {
-      assert(pu_y >> 2 > 0);
-      // Get mip flag from above PU
-      ctx_id += kvz_cu_array_at_const(frame->cu_array, pu_x, pu_y - 1)->intra.mip_flag ? 1 : 0;
-    }
-    ctx_id = (cu_width > 2 * cu_height || cu_height > 2 * cu_width) ? 3 : ctx_id;
 
     // Write MIP flag
     cabac->cur_ctx = &(cabac->ctx.mip_flag[ctx_id]);

src/intra.c

@@ -546,37 +546,41 @@ void kvz_predict_cclm(
 }
 
 
+int kvz_get_mip_flag_context(int x, int y, int width, int height, lcu_t* const lcu, cu_array_t* const cu_a) {
+  assert(!(lcu && cu_a));
+  int context = 0;
+  
+  if (lcu) {
+    int x_local = SUB_SCU(x);
+    int y_local = SUB_SCU(y);
+    if (x) {
+      context += LCU_GET_CU_AT_PX(lcu, x_local - 1, y_local)->intra.mip_flag;
+    }
+    if (y) {
+      context += LCU_GET_CU_AT_PX(lcu, x_local, y_local - 1)->intra.mip_flag;
+    }
+    context = (width > 2 * height || height > 2 * width) ? 3 : context;
+  }
+  else {
+    if (x > 0) {
+      context += kvz_cu_array_at_const(cu_a, x - 1, y)->intra.mip_flag;
+    }
+    if (y > 0) {
+      context += kvz_cu_array_at_const(cu_a, x, y - 1)->intra.mip_flag;
+    }
+    context = (width > 2 * height || height > 2 * width) ? 3 : context;
+  }
+  return context;
+}
+
+
 void kvz_mip_boundary_downsampling_1D(kvz_pixel* reduced_dst, const kvz_pixel* const ref_src, int src_len, int dst_len)
 {
   if (dst_len < src_len)
   {
     // Create reduced boundary by downsampling
     uint16_t down_smp_factor = src_len / dst_len;
-
+    const int log2_factor = kvz_math_floor_log2(down_smp_factor);
-    // Calculate floor log2. MIP_TODO: find a better / faster solution
-    int tmp = 0;
-    if (down_smp_factor & 0xffff0000) {
-      down_smp_factor >>= 16;
-      tmp += 16;
-    }
-    if (down_smp_factor & 0xff00) {
-      down_smp_factor >>= 8;
-      tmp += 8;
-    }
-    if (down_smp_factor & 0xf0) {
-      down_smp_factor >>= 4;
-      tmp += 4;
-    }
-    if (down_smp_factor & 0xc) {
-      down_smp_factor >>= 2;
-      tmp += 2;
-    }
-    if (down_smp_factor & 0x2) {
-      down_smp_factor >>= 1;
-      tmp += 1;
-    }
-
-    const int log2_factor = tmp;
     const int rounding_offset = (1 << (log2_factor - 1));
 
     uint16_t src_idx = 0;
@@ -667,31 +671,7 @@ void kvz_mip_pred_upsampling_1D(kvz_pixel* const dst, const kvz_pixel* const src
                                 const uint16_t boundary_step,
                                 const uint16_t ups_factor)
 {
-  // Calculate floor log2. MIP_TODO: find a better / faster solution
+  const int log2_factor = kvz_math_floor_log2(ups_factor);
-  uint16_t upsample_factor = ups_factor;
-  int tmp = 0;
-  if (upsample_factor & 0xffff0000) {
-    upsample_factor >>= 16;
-    tmp += 16;
-  }
-  if (upsample_factor & 0xff00) {
-    upsample_factor >>= 8;
-    tmp += 8;
-  }
-  if (upsample_factor & 0xf0) {
-    upsample_factor >>= 4;
-    tmp += 4;
-  }
-  if (upsample_factor & 0xc) {
-    upsample_factor >>= 2;
-    tmp += 2;
-  }
-  if (upsample_factor & 0x2) {
-    upsample_factor >>= 1;
-    tmp += 1;
-  }
-
-  const int log2_factor = tmp;
   assert(ups_factor >= 2 && "Upsampling factor must be at least 2.");
   const int rounding_offset = 1 << (log2_factor - 1);
 

src/intra.h

@@ -150,6 +150,8 @@ void kvz_predict_cclm(
   cclm_parameters_t* cclm_params
 );
 
+int kvz_get_mip_flag_context(int x, int y, int width, int height, lcu_t* const lcu, cu_array_t* const cu_a);
+
 void kvz_mip_predict(
   encoder_state_t const * const state,
   kvz_intra_references * refs,

src/search_intra.c

@@ -726,11 +726,11 @@ static int8_t search_intra_rdo(encoder_state_t * const state,
 {
   const int tr_depth = CLIP(1, MAX_PU_DEPTH, depth + state->encoder_control->cfg.tr_depth_intra);
   const int width = LCU_WIDTH >> depth;
+  const int height = width; // TODO: proper height for non-square blocks
 
   kvz_pixel orig_block[LCU_WIDTH * LCU_WIDTH + 1];
 
-  // TODO: height for non-square blocks
+  kvz_pixels_blit(orig, orig_block, width, height, origstride, width);
-  kvz_pixels_blit(orig, orig_block, width, width, origstride, width);
 
   // Check that the predicted modes are in the RDO mode list
   if (modes_to_check < 67) {
@@ -756,46 +756,19 @@ static int8_t search_intra_rdo(encoder_state_t * const state,
   }
 
   // MIP_TODO: implement this inside the standard intra for loop. Code duplication is bad.
-  // MIP_TODO: deriving mip flag context id could be done in it's own function since the exact same code is used in encode_coding_tree.c
   // MIP search
   const int transp_off = num_mip_modes >> 1;
   for (uint8_t mip_mode = 0; mip_mode < num_mip_modes; ++mip_mode) {
     // Derive mip flag context id
-    uint8_t ctx_id = 0;
+    uint8_t ctx_id = kvz_get_mip_flag_context(x_px, y_px, width, height, lcu, NULL);
-    const videoframe_t* const frame = state->tile->frame;
-    const vector2d_t lcu_px = { SUB_SCU(x_px), SUB_SCU(y_px) };
-    cu_info_t* cur_cu;
-    cur_cu = LCU_GET_CU_AT_PX(lcu, lcu_px.x, lcu_px.y);
-    const int cu_width = width;
-    const int cu_height = cu_width; // TODO: height for non-square blocks
-    const int pu_x = PU_GET_X(cur_cu->part_size, cu_width, x_px, 0);
-    const int pu_y = PU_GET_Y(cur_cu->part_size, cu_width, y_px, 0);
-    const cu_info_t* left_pu = NULL;
-    const cu_info_t* above_pu = NULL;
-
-    if (pu_x > 0) {
-      assert(pu_x >> 2 > 0);
-      left_pu = kvz_cu_array_at_const(frame->cu_array, pu_x - 1, pu_y + cu_width - 1);
-    }
-    if (left_pu != NULL) {
-      ctx_id = left_pu->intra.mip_flag ? 1 : 0;
-    }
-    // Don't take the above PU across the LCU boundary.
-    if (pu_y % LCU_WIDTH > 0 && pu_y > 0) {
-      assert(pu_y >> 2 > 0);
-      above_pu = kvz_cu_array_at_const(frame->cu_array, pu_x + cu_width - 1, pu_y - 1);
-    }
-    if (above_pu != NULL) {
-      ctx_id += above_pu->intra.mip_flag ? 1 : 0;
-    }
-    ctx_id = (cu_width > 2 * cu_height || cu_height > 2 * cu_width) ? 3 : ctx_id;
     int rdo_bitcost = kvz_luma_mode_bits(state, mip_modes[mip_mode], intra_preds, 0, num_mip_modes, ctx_id);
 
     mip_costs[mip_mode] = rdo_bitcost * (int)(state->lambda + 0.5); // MIP_TODO: check if this is also correct in the case when MIP is used.
 
     const bool is_transposed = (mip_modes[mip_mode] >= transp_off ? true : false);
     // There can be 32 MIP modes, but only mode numbers [0, 15] are ever written to bitstream.
-    // Modes [16, 31] are indicated with the separate transpose flag.
+    // Half of the modes [16, 31] are indicated with the separate transpose flag.
+    // Number of possible modes is less for larger blocks.
     int8_t pred_mode = (is_transposed ? mip_modes[mip_mode] - transp_off : mip_modes[mip_mode]);
 
     // Perform transform split search and save mode RD cost for the best one.
@@ -1244,11 +1217,11 @@ void kvz_search_cu_intra(encoder_state_t * const state,
       num_mip_modes = 32;
     }
     else if (width == 4 || height == 4 || (width == 8 && height == 8)) {
-      // Mip size_id = 0. Num modes = 16
+      // Mip size_id = 1. Num modes = 16
       num_mip_modes = 16;
     }
     else {
-      // Mip size_id = 0. Num modes = 12
+      // Mip size_id = 2. Num modes = 12
       num_mip_modes = 12;
     }
   }
@@ -1358,6 +1331,12 @@ void kvz_search_cu_intra(encoder_state_t * const state,
     }
   }
 
+  if (tmp_mip_flag) {
+    // Transform best mode index to proper form.
+    // Max mode index is half of max number of modes - 1 (i. e. for size id 2, max mode id is 5)
+    tmp_best_mode = (tmp_mip_transp ? tmp_best_mode - (num_mip_modes >> 1) : tmp_best_mode);
+  }
+
   *mode_out =  tmp_best_mode;
   *trafo_out = tmp_best_trafo;
   *cost_out =  tmp_best_cost;