dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2024-12-25 13:18:22 +01:00
Code Issues Actions Packages Projects Releases Wiki Activity

speed up GetResidualCost()

Browse Source 
* 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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
src/enc/frame.c
View File

@ -113,7 +113,8 @@ static int Record(int bit, proba_t* const stats) {
// Note: no need to record the fixed probas. // Note: no need to record the fixed probas.
static int RecordCoeffs(int ctx, const VP8Residual* const res) { static int RecordCoeffs(int ctx, const VP8Residual* const res) {
int n = res->first; 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) { if (res->last < 0) {
Record(0, s + 0); Record(0, s + 0);
return 0; return 0;
@ -282,16 +283,17 @@ static void SetResidualCoeffs(const int16_t* const coeffs,
static int GetResidualCost(int ctx, const VP8Residual* const res) { static int GetResidualCost(int ctx, const VP8Residual* const res) {
int n = res->first; int n = res->first;
int p0 = res->prob[VP8EncBands[n]][ctx][0]; // should be prob[VP8EncBands[n]], but it's equivalent for n=0 or 1
const uint16_t* t = res->cost[VP8EncBands[n]][ctx]; int p0 = res->prob[n][ctx][0];
const uint16_t* t = res->cost[n][ctx];
int cost; int cost;
if (res->last < 0) { if (res->last < 0) {
return VP8BitCost(0, p0); return VP8BitCost(0, p0);
} }
cost = 0; cost = 0;
while (n <= res->last) { while (n < res->last) {
const int v = res->coeffs[n]; int v = res->coeffs[n];
const int b = VP8EncBands[n + 1]; const int b = VP8EncBands[n + 1];
++n; ++n;
if (v == 0) { if (v == 0) {
@ -300,19 +302,28 @@ static int GetResidualCost(int ctx, const VP8Residual* const res) {
t = res->cost[b][0]; t = res->cost[b][0];
continue; continue;
} }
v = abs(v);
cost += VP8BitCost(1, p0); cost += VP8BitCost(1, p0);
if (2u >= (unsigned int)(v + 1)) { // v = -1 or 1 cost += VP8LevelCost(t, v);
// short-case for "VP8LevelCost(t, 1)" (256 is VP8LevelFixedCosts[1]): {
cost += 256 + t[1]; const int ctx = (v == 1) ? 1 : 2;
p0 = res->prob[b][1][0]; p0 = res->prob[b][ctx][0];
t = res->cost[b][1]; t = res->cost[b][ctx];
} else { }
cost += VP8LevelCost(t, abs(v)); }
p0 = res->prob[b][2][0]; // Last coefficient is always non-zero
t = res->cost[b][2]; {
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; 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) { static int PutCoeffs(VP8BitWriter* const bw, int ctx, const VP8Residual* res) {
int n = res->first; 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])) { if (!VP8PutBit(bw, res->last >= 0, p[0])) {
return 0; return 0;
} }