From 7f23678da0bf546c9b8e11cca6bf28647691fc3c Mon Sep 17 00:00:00 2001
From: Pascal Massimino <pascal.massimino@gmail.com>
Date: Mon, 23 Jan 2012 09:17:35 -0800
Subject: [PATCH] fix for LevelCost + little speed-up

the p0 proba was incorrectly accumulated. Merging its contribution into
the LevelCost[] was creating more problems than anything (esp. with trellis)
so let's just not.

Change-Id: I4c07bfee471085df901228d97b20a4d9606ba44e
---
 src/enc/cost.c  | 2 +-
 src/enc/frame.c | 7 +++++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/enc/cost.c b/src/enc/cost.c
index 1eead3fa..14b357ba 100644
--- a/src/enc/cost.c
+++ b/src/enc/cost.c
@@ -359,7 +359,7 @@ void VP8CalculateLevelCosts(VP8Proba* const proba) {
       for(ctx = 0; ctx < NUM_CTX; ++ctx) {
         const uint8_t* const p = proba->coeffs_[ctype][band][ctx];
         uint16_t* const table = proba->level_cost_[ctype][band][ctx];
-        const int cost_base = VP8BitCost(0, p[0]) + VP8BitCost(1, p[1]);
+        const int cost_base = VP8BitCost(1, p[1]);
         int v;
         table[0] = VP8BitCost(0, p[1]);
         for (v = 1; v <= MAX_VARIABLE_LEVEL; ++v) {
diff --git a/src/enc/frame.c b/src/enc/frame.c
index 8a958f2e..f9fbdf2d 100644
--- a/src/enc/frame.c
+++ b/src/enc/frame.c
@@ -274,12 +274,15 @@ static int GetResidualCost(int ctx, const VP8Residual* const res) {
     const int b = VP8EncBands[n + 1];
     ++n;
     if (v == 0) {
-      cost += VP8LevelCost(t, 0);
+      // short-case for VP8LevelCost(t, 0) (note: VP8LevelFixedCosts[0] == 0):
+      cost += t[0];
       t = res->cost[b][0];
       continue;
     }
+    cost += VP8BitCost(1, p0);
     if (2u >= (unsigned int)(v + 1)) {   // v = -1 or 1
-      cost += VP8LevelCost(t, 1);
+      // short-case for "VP8LevelCost(t, 1)" (256 is VP8LevelFixedCosts[1]):
+      cost += 256 + t[1];
       p0 = res->prob[b][1][0];
       t = res->cost[b][1];
     } else {