shithub: libvpx

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Miscelleneous changes in detokenize for speed

Changes to reduce branching in detokenization  in order
to improve decode speed.

Change-Id: I23a74d072cc14d99f6fc054c1e6a72021e777903

--- a/vp9/decoder/vp9_detokenize.c

+++ b/vp9/decoder/vp9_detokenize.c

@@ -61,16 +61,18 @@

   254, 254, 254, 252, 249, 243, 230, 196, 177, 153, 140, 133, 130, 129, 0

 };

+static const int token_to_counttoken[MAX_ENTROPY_TOKENS] = {

+  ZERO_TOKEN, ONE_TOKEN, TWO_TOKEN, TWO_TOKEN,

+  TWO_TOKEN, TWO_TOKEN, TWO_TOKEN, TWO_TOKEN,

+  TWO_TOKEN, TWO_TOKEN, TWO_TOKEN, DCT_EOB_MODEL_TOKEN

+};

+

 #define INCREMENT_COUNT(token)                           \

   do {                                                   \

-    if (!cm->frame_parallel_decoding_mode) {             \

-      ++coef_counts[type][ref][band][pt]                 \

-                   [token >= TWO_TOKEN ?                 \

-                    (token == DCT_EOB_TOKEN ?            \

-                     DCT_EOB_MODEL_TOKEN : TWO_TOKEN) :  \

-                    token];                              \

-    }                                                    \

-  } while (0)

+     if (!cm->frame_parallel_decoding_mode) {            \

+       ++coef_counts[band][pt][token_to_counttoken[token]]; \

+     }                                                   \

+  } while (0);

 #define WRITE_COEF_CONTINUE(val, token)                  \

   {                                                      \

@@ -102,7 +104,10 @@

   vp9_prob coef_probs_full[COEF_BANDS][PREV_COEF_CONTEXTS][ENTROPY_NODES];

   uint8_t load_map[COEF_BANDS][PREV_COEF_CONTEXTS] = { { 0 } };

   const vp9_prob *prob;

-  vp9_coeff_count_model *coef_counts = counts->coef[tx_size];

+  unsigned int (*coef_counts)[PREV_COEF_CONTEXTS][UNCONSTRAINED_NODES + 1] =

+      counts->coef[tx_size][type][ref];

+  unsigned int (*eob_branch_count)[PREV_COEF_CONTEXTS] =

+      counts->eob_branch[tx_size][type][ref];

   const int16_t *scan, *nb;

   const uint8_t *const band_translate = get_band_translate(tx_size);

   get_scan(xd, tx_size, type, block_idx, &scan, &nb);

@@ -117,7 +122,7 @@

     band = get_coef_band(band_translate, c);

     prob = coef_probs[band][pt];

     if (!cm->frame_parallel_decoding_mode)

-      ++counts->eob_branch[tx_size][type][ref][band][pt];

+      ++eob_branch_count[band][pt];

     if (!vp9_read(r, prob[EOB_CONTEXT_NODE]))

       break;

@@ -205,7 +210,7 @@

   if (c < seg_eob) {

     if (!cm->frame_parallel_decoding_mode)

-      ++coef_counts[type][ref][band][pt][DCT_EOB_MODEL_TOKEN];

+      ++coef_counts[band][pt][DCT_EOB_MODEL_TOKEN];

   }

   return c;