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Speedup TrellisQuantizeBlock().

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-Skip examining quantized levels that are too high.
-Calculate last_pos_cost only when needed.

Encoding speed for m6 is increased by about 3%;
Compression performance is neutral.

Change-Id: I8af70b049587cca0375d9b3eb00479ec7c0c842a
This commit is contained in:
hui su 2016-09-20 14:54:15 -07:00
parent 573cce270e
commit a2fe9bf404
1 changed files with 8 additions and 9 deletions
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17
src/enc/quant.c
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@ -643,6 +643,8 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
const int sign = (in[j] < 0);
const uint32_t coeff0 = (sign ? -in[j] : in[j]) + mtx->sharpen_[j];
int level0 = QUANTDIV(coeff0, iQ, B);
int thresh_level = QUANTDIV(coeff0, iQ, BIAS(0x80));
if (thresh_level > MAX_LEVEL) thresh_level = MAX_LEVEL;
if (level0 > MAX_LEVEL) level0 = MAX_LEVEL;
{ // Swap current and previous score states
@ -657,23 +659,17 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
int level = level0 + m;
const int ctx = (level > 2) ? 2 : level;
const int band = VP8EncBands[n + 1];
score_t base_score, last_pos_score;
score_t base_score;
score_t best_cur_score = MAX_COST;
int best_prev = 0; // default, in case
ss_cur[m].score = MAX_COST;
ss_cur[m].costs = costs[n + 1][ctx];
if (level > MAX_LEVEL || level < 0) { // node is dead?
if (level < 0 || level > thresh_level) {
// Node is dead.
continue;
}
// Compute extra rate cost if last coeff's position is < 15
{
const score_t last_pos_cost =
(n < 15) ? VP8BitCost(0, probas[band][ctx][0]) : 0;
last_pos_score = RDScoreTrellis(lambda, last_pos_cost, 0);
}
{
// Compute delta_error = how much coding this level will
// subtract to max_error as distortion.
@ -705,6 +701,9 @@ static int TrellisQuantizeBlock(const VP8Encoder* const enc,
// Now, record best terminal node (and thus best entry in the graph).
if (level != 0) {
const score_t last_pos_cost =
(n < 15) ? VP8BitCost(0, probas[band][ctx][0]) : 0;
const score_t last_pos_score = RDScoreTrellis(lambda, last_pos_cost, 0);
const score_t score = best_cur_score + last_pos_score;
if (score < best_score) {
best_score = score;