shithub: libvpx

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Minor change in forward updates

Removes the case of coding prob = 0 for forward updates, since that
is not an allowed probability to code.
Slightly improves efficiency but may not matter in practice.

Change-Id: I3b4caf82e8f0891992f0706d4089cc5a27568dba

--- a/vp9/decoder/vp9_decodframe.c

+++ b/vp9/decoder/vp9_decodframe.c

@@ -156,13 +156,14 @@

 }

 static int inv_remap_prob(int v, int m) {

-  const int n = 256;

+  const int n = 255;

   v = merge_index(v, n - 1, MODULUS_PARAM);

+  m--;

   if ((m << 1) <= n) {

-    return inv_recenter_nonneg(v + 1, m);

+    return 1 + inv_recenter_nonneg(v + 1, m);

   } else {

-    return n - 1 - inv_recenter_nonneg(v + 1, n - 1 - m);

+    return n - inv_recenter_nonneg(v + 1, n - 1 - m);

   }

 }

--- a/vp9/encoder/vp9_bitstream.c

+++ b/vp9/encoder/vp9_bitstream.c

@@ -265,7 +265,7 @@

 static void compute_update_table() {

   int i;

-  for (i = 0; i < 255; i++)

+  for (i = 0; i < 254; i++)

     update_bits[i] = count_term_subexp(i, SUBEXP_PARAM, 255);

 }

@@ -277,9 +277,11 @@

 }

 static int remap_prob(int v, int m) {

-  const int n = 256;

+  const int n = 255;

   const int modulus = MODULUS_PARAM;

   int i;

+  v--;

+  m--;

   if ((m << 1) <= n)

     i = recenter_nonneg(v, m) - 1;

   else

-- 

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