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speed up GetResidualCost()

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* treat the last coeff as a special case
* re-arrange the inner code to be shorter
* replace some VP8EncBands[n] by n, for n = 0 or 1

Change-Id: I71e17b014cffad7b073e787fde06260905a6953f
This commit is contained in:
skal 2012-11-26 23:50:37 +01:00
parent ba2aa0fdda
commit f76191f9db
1 changed files with 28 additions and 16 deletions
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44
src/enc/frame.c
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@ -113,7 +113,8 @@ static int Record(int bit, proba_t* const stats) {
// Note: no need to record the fixed probas.
static int RecordCoeffs(int ctx, const VP8Residual* const res) {
int n = res->first;
proba_t* s = res->stats[VP8EncBands[n]][ctx];
// should be stats[VP8EncBands[n]], but it's equivalent for n=0 or 1
proba_t* s = res->stats[n][ctx];
if (res->last < 0) {
Record(0, s + 0);
return 0;
@ -282,16 +283,17 @@ static void SetResidualCoeffs(const int16_t* const coeffs,
static int GetResidualCost(int ctx, const VP8Residual* const res) {
int n = res->first;
int p0 = res->prob[VP8EncBands[n]][ctx][0];
const uint16_t* t = res->cost[VP8EncBands[n]][ctx];
// should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1
int p0 = res->prob[n][ctx][0];
const uint16_t* t = res->cost[n][ctx];
int cost;
if (res->last < 0) {
return VP8BitCost(0, p0);
}
cost = 0;
while (n <= res->last) {
const int v = res->coeffs[n];
while (n < res->last) {
int v = res->coeffs[n];
const int b = VP8EncBands[n + 1];
++n;
if (v == 0) {
@ -300,19 +302,28 @@ static int GetResidualCost(int ctx, const VP8Residual* const res) {
t = res->cost[b][0];
continue;
}
v = abs(v);
cost += VP8BitCost(1, p0);
if (2u >= (unsigned int)(v + 1)) { // v = -1 or 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 {
cost += VP8LevelCost(t, abs(v));
p0 = res->prob[b][2][0];
t = res->cost[b][2];
cost += VP8LevelCost(t, v);
{
const int ctx = (v == 1) ? 1 : 2;
p0 = res->prob[b][ctx][0];
t = res->cost[b][ctx];
}
}
// Last coefficient is always non-zero
{
const int v = abs(res->coeffs[n]);
assert(v != 0);
cost += VP8BitCost(1, p0);
cost += VP8LevelCost(t, v);
if (n < 15) {
const int b = VP8EncBands[n + 1];
const int ctx = (v == 1) ? 1 : 2;
const int p0 = res->prob[b][ctx][0];
cost += VP8BitCost(0, p0);
}
}
if (n < 16) cost += VP8BitCost(0, p0);
return cost;
}
@ -383,7 +394,8 @@ int VP8GetCostUV(VP8EncIterator* const it, const VP8ModeScore* const rd) {
static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) {
int n = res->first;
const uint8_t* p = res->prob[VP8EncBands[n]][ctx];
// should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1
const uint8_t* p = res->prob[n][ctx];
if (!VP8PutBit(bw, res->last >= 0, p[0])) {
return 0;
}