[mip] Implement MIP bit cost calculation.

src/cu.h

@@ -169,8 +169,8 @@ typedef struct
       int8_t mode;
       int8_t mode_chroma;
       uint8_t multi_ref_idx;
-      uint8_t mip_flag;
+      int8_t mip_flag;
-      uint8_t mip_is_transposed;
+      int8_t mip_is_transposed;
     } intra;
     struct {
       mv_t    mv[2][2];  // \brief Motion vectors for L0 and L1

src/search.c

@@ -502,7 +502,8 @@ static double calc_mode_bits(const encoder_state_t *state,
     kvz_intra_get_dir_luma_predictor(x, y, candidate_modes, cur_cu, left_cu, above_cu);
   }
 
-  double mode_bits = kvz_luma_mode_bits(state, cur_cu->intra.mode, candidate_modes, cur_cu->intra.multi_ref_idx);
+  // MIP_TODO: calculation of MIP mode cost if this CU has MIP enabled.
+  double mode_bits = kvz_luma_mode_bits(state, cur_cu->intra.mode, candidate_modes, cur_cu->intra.multi_ref_idx, 0);
 
   if (((depth == 4 && x % 8 && y % 8) || (depth != 4)) && state->encoder_control->chroma_format != KVZ_CSP_400) {
     mode_bits += kvz_chroma_mode_bits(state, cur_cu->intra.mode_chroma, cur_cu->intra.mode);

src/search_intra.c

@@ -679,7 +679,7 @@ static int8_t search_intra_rough(encoder_state_t * const state,
   // affecting the halving search.
   int lambda_cost = (int)(state->lambda_sqrt + 0.5);
   for (int mode_i = 0; mode_i < modes_selected; ++mode_i) {
-    costs[mode_i] += lambda_cost * kvz_luma_mode_bits(state, modes[mode_i], intra_preds, 0);
+    costs[mode_i] += lambda_cost * kvz_luma_mode_bits(state, modes[mode_i], intra_preds, 0, 0);
   }
 
   #undef PARALLEL_BLKS
@@ -759,7 +759,7 @@ static int8_t search_intra_rdo(encoder_state_t * const state,
   // MIP search
   const int transp_off = num_mip_modes >> 1;
   for (uint8_t mip_mode = 0; mip_mode < num_mip_modes; ++mip_mode) {
-    int rdo_bitcost = kvz_mip_mode_bits(state, mip_mode, num_mip_modes);
+    int rdo_bitcost = kvz_luma_mode_bits(state, mip_modes[mip_mode], intra_preds, 0, num_mip_modes);
 
     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.
 
@@ -797,7 +797,7 @@ static int8_t search_intra_rdo(encoder_state_t * const state,
   }
 
   for(int rdo_mode = 0; rdo_mode < modes_to_check; rdo_mode ++) {
-    int rdo_bitcost = kvz_luma_mode_bits(state, modes[rdo_mode], intra_preds, multi_ref_idx);
+    int rdo_bitcost = kvz_luma_mode_bits(state, modes[rdo_mode], intra_preds, multi_ref_idx, 0);
 
     costs[rdo_mode] = rdo_bitcost * (int)(state->lambda + 0.5);
 
@@ -853,20 +853,42 @@ static int8_t search_intra_rdo(encoder_state_t * const state,
 }
 
 
-double kvz_mip_mode_bits(const encoder_state_t *state, int mip_mode, int num_mip_modes)
+double kvz_luma_mode_bits(const encoder_state_t *state, int8_t luma_mode, const int8_t *intra_preds, const uint8_t multi_ref_idx, const uint8_t num_mip_modes)
 {
   double mode_bits = 0.0;
 
-  // MIP_TODO: calculate bit costs of writing the following: mip_flag, mip_transpose_flag & mip_mode
+  bool enable_mip = state->encoder_control->cfg.mip ? (num_mip_modes > 0 ? true : false) : false;
 
-  return mode_bits;
+  if (enable_mip) {
+    // Make a copy of state->cabac for bit cost estimation.
+    cabac_data_t state_cabac_copy;
+    cabac_data_t* cabac;
+    memcpy(&state_cabac_copy, &state->cabac, sizeof(cabac_data_t));
+    // Clear data and set mode to count only
+    state_cabac_copy.only_count = 1;
+    state_cabac_copy.num_buffered_bytes = 0;
+    state_cabac_copy.bits_left = 23;
+
+    cabac = &state_cabac_copy;
+
+    // Do cabac writes as normal
+    const int transp_off = num_mip_modes >> 1;
+    bool mip_flag = enable_mip;
+    const bool is_transposed = luma_mode >= transp_off ? true : false;
+    int8_t mip_mode = is_transposed ? luma_mode - transp_off : luma_mode;
+    // Write MIP flag
+    cabac->cur_ctx = &(cabac->ctx.mip_flag);
+    CABAC_BIN(cabac, mip_flag, "mip_flag");
+    if (mip_flag) {
+      // Write MIP transpose flag & mode
+      CABAC_BIN_EP(cabac, is_transposed, "mip_transposed");
+      kvz_cabac_encode_trunc_bin(cabac, mip_mode, transp_off);
     }
 
-
+    // Writes done. Get bit cost out of cabac
-double kvz_luma_mode_bits(const encoder_state_t *state, int8_t luma_mode, const int8_t *intra_preds, const uint8_t multi_ref_idx)
+    mode_bits += (23 - state_cabac_copy.bits_left) + (state_cabac_copy.num_buffered_bytes << 3); // MIP_TODO: check what this bit shifting means.
-{
+  }
-  double mode_bits = 0.0;
+  else {
-
     int8_t mode_in_preds = -1;
     for (int i = 0; i < INTRA_MPM_COUNT; ++i) {
       if (luma_mode == intra_preds[i]) {
@@ -901,9 +923,11 @@ double kvz_luma_mode_bits(const encoder_state_t *state, int8_t luma_mode, const
         mode_bits += CTX_ENTROPY_FBITS(ctx, mode_in_preds > 0);
       }
       mode_bits += MIN(4.0, mode_in_preds);
-  } else {
+    }
+    else {
       mode_bits += 6.0;
     }
+  }
 
   return mode_bits;
 }

src/search_intra.h

@@ -43,10 +43,8 @@
 #include "global.h" // IWYU pragma: keep
 #include "intra.h"
 
-double kvz_mip_mode_bits(const encoder_state_t *state, int mip_mode, int num_mip_modes);
-
 double kvz_luma_mode_bits(const encoder_state_t *state, 
-                          int8_t luma_mode, const int8_t *intra_preds, uint8_t multi_ref_idx);
+                          int8_t luma_mode, const int8_t *intra_preds, uint8_t multi_ref_idx, const uint8_t num_mip_modes);
                        
 double kvz_chroma_mode_bits(const encoder_state_t *state,
                         int8_t chroma_mode, int8_t luma_mode);