Residual coding to cache energy class of tokens.

Proposal for tuning the residual coding by changing how the context
from previous tokens is calculated. Storing the energy class of previous
tokens instead of the token itself eases the critical path of
HW implementations.

Change-Id: I6d71d856b84518f6c88de771ddd818436f794bab

diff --git a/vp9/common/vp9_entropy.c b/vp9/common/vp9_entropy.c
index 847fee6..1ae3586 100644 (file)
--- a/vp9/common/vp9_entropy.c
+++ b/vp9/common/vp9_entropy.c
@@ -468,7 +468,7 @@ int vp9_get_coef_context(const int *scan, const int *neighbors,
     } else {
       ctx = token_cache[scan[neighbors[MAX_NEIGHBORS * c + 0]]];
     }
-    return vp9_pt_energy_class[ctx];
+    return ctx;
   }
 };
 

diff --git a/vp9/decoder/vp9_detokenize.c b/vp9/decoder/vp9_detokenize.c
index 02900c0..890d5d0 100644 (file)
--- a/vp9/decoder/vp9_detokenize.c
+++ b/vp9/decoder/vp9_detokenize.c
@@ -58,13 +58,15 @@ static const vp9_prob cat6_prob[15] = {
   254, 254, 254, 252, 249, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0
 };
 
+DECLARE_ALIGNED(16, extern const uint8_t,
+                vp9_pt_energy_class[MAX_ENTROPY_TOKENS]);
 #define INCREMENT_COUNT(token)               \
   do {                                       \
     coef_counts[type][ref][band][pt]         \
                [token >= TWO_TOKEN ?     \
                 (token == DCT_EOB_TOKEN ? DCT_EOB_MODEL_TOKEN : TWO_TOKEN) : \
                 token]++;     \
-    token_cache[scan[c]] = token; \
+    token_cache[scan[c]] = vp9_pt_energy_class[token]; \
   } while (0)
 
 #define WRITE_COEF_CONTINUE(val, token)                  \

diff --git a/vp9/encoder/vp9_encodemb.c b/vp9/encoder/vp9_encodemb.c
index b7f60b1..62ef9a0 100644 (file)
--- a/vp9/encoder/vp9_encodemb.c
+++ b/vp9/encoder/vp9_encodemb.c
@@ -20,6 +20,9 @@
 #include "vp9/common/vp9_systemdependent.h"
 #include "vp9_rtcd.h"
 
+DECLARE_ALIGNED(16, extern const uint8_t,
+                vp9_pt_energy_class[MAX_ENTROPY_TOKENS]);
+
 void vp9_subtract_block(int rows, int cols,
                         int16_t *diff_ptr, int diff_stride,
                         const uint8_t *src_ptr, int src_stride,
@@ -105,7 +108,7 @@ static int trellis_get_coeff_context(const int *scan,
                                      uint8_t *token_cache,
                                      int pad, int l) {
   int bak = token_cache[scan[idx]], pt;
-  token_cache[scan[idx]] = token;
+  token_cache[scan[idx]] = vp9_pt_energy_class[token];
   pt = vp9_get_coef_context(scan, nb, pad, token_cache, idx + 1, l);
   token_cache[scan[idx]] = bak;
   return pt;
@@ -189,7 +192,8 @@ static void optimize_b(VP9_COMMON *const cm, MACROBLOCK *mb,
   *(tokens[eob] + 1) = *(tokens[eob] + 0);
   next = eob;
   for (i = 0; i < eob; i++)
-    token_cache[scan[i]] = vp9_dct_value_tokens_ptr[qcoeff_ptr[scan[i]]].token;
+    token_cache[scan[i]] = vp9_pt_energy_class[vp9_dct_value_tokens_ptr[
+        qcoeff_ptr[scan[i]]].token];
   nb = vp9_get_coef_neighbors_handle(scan, &pad);
 
   for (i = eob; i-- > i0;) {

diff --git a/vp9/encoder/vp9_rdopt.c b/vp9/encoder/vp9_rdopt.c
index 2eb3f9b..aaba2bb 100644 (file)
--- a/vp9/encoder/vp9_rdopt.c
+++ b/vp9/encoder/vp9_rdopt.c
@@ -46,6 +46,9 @@
 /* Factor to weigh the rate for switchable interp filters */
 #define SWITCHABLE_INTERP_RATE_FACTOR 1
 
+DECLARE_ALIGNED(16, extern const uint8_t,
+                vp9_pt_energy_class[MAX_ENTROPY_TOKENS]);
+
 const MODE_DEFINITION vp9_mode_order[MAX_MODES] = {
   {ZEROMV,    LAST_FRAME,   NONE},
   {DC_PRED,   INTRA_FRAME,  NONE},
@@ -366,7 +369,7 @@ static INLINE int cost_coeffs(VP9_COMMON *const cm, MACROBLOCK *mb,
 
       if (!c || token_cache[scan[c - 1]])
         cost += vp9_cost_bit(coef_probs[band][pt][0], 1);
-      token_cache[scan[c]] = t;
+      token_cache[scan[c]] = vp9_pt_energy_class[t];
     }
     if (c < seg_eob) {
       if (c)

diff --git a/vp9/encoder/vp9_tokenize.c b/vp9/encoder/vp9_tokenize.c
index 08efc84..eb79de1 100644 (file)
--- a/vp9/encoder/vp9_tokenize.c
+++ b/vp9/encoder/vp9_tokenize.c
@@ -36,6 +36,9 @@ extern vp9_coeff_stats tree_update_hist_16x16[BLOCK_TYPES];
 extern vp9_coeff_stats tree_update_hist_32x32[BLOCK_TYPES];
 #endif  /* ENTROPY_STATS */
 
+DECLARE_ALIGNED(16, extern const uint8_t,
+                vp9_pt_energy_class[MAX_ENTROPY_TOKENS]);
+
 static TOKENVALUE dct_value_tokens[DCT_MAX_VALUE * 2];
 const TOKENVALUE *vp9_dct_value_tokens_ptr;
 static int dct_value_cost[DCT_MAX_VALUE * 2];
@@ -228,7 +231,7 @@ static void tokenize_b(int plane, int block, BLOCK_SIZE_TYPE bsize,
       if (!t->skip_eob_node)
         ++cpi->common.fc.eob_branch_counts[tx_size][type][ref][band][pt];
     }
-    token_cache[scan[c]] = token;
+    token_cache[scan[c]] = vp9_pt_energy_class[token];
     ++t;
   } while (c < eob && ++c < seg_eob);