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remove call to MBAnalyzeBestIntra4Mode for method >= 5

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this was not giving a good alpha value, making the method 5/6 a little
blurrier than method 4 (!).

Change-Id: I69b9890dea21499c1af1753e87d9f7adf8b433de
This commit is contained in:
Skal 2020-02-07 14:36:10 +01:00
parent 71690b524e
commit a99078c1cf
1 changed files with 0 additions and 60 deletions
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60
src/enc/analysis_enc.c
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@ -126,16 +126,6 @@ static void InitHistogram(VP8Histogram* const histo) {
histo->last_non_zero = 1;
}
static void MergeHistograms(const VP8Histogram* const in,
VP8Histogram* const out) {
if (in->max_value > out->max_value) {
out->max_value = in->max_value;
}
if (in->last_non_zero > out->last_non_zero) {
out->last_non_zero = in->last_non_zero;
}
}
//------------------------------------------------------------------------------
// Simplified k-Means, to assign Nb segments based on alpha-histogram
@ -285,49 +275,6 @@ static int FastMBAnalyze(VP8EncIterator* const it) {
return 0;
}
static int MBAnalyzeBestIntra4Mode(VP8EncIterator* const it,
int best_alpha) {
uint8_t modes[16];
const int max_mode = MAX_INTRA4_MODE;
int i4_alpha;
VP8Histogram total_histo;
int cur_histo = 0;
InitHistogram(&total_histo);
VP8IteratorStartI4(it);
do {
int mode;
int best_mode_alpha = DEFAULT_ALPHA;
VP8Histogram histos[2];
const uint8_t* const src = it->yuv_in_ + Y_OFF_ENC + VP8Scan[it->i4_];
VP8MakeIntra4Preds(it);
for (mode = 0; mode < max_mode; ++mode) {
int alpha;
InitHistogram(&histos[cur_histo]);
VP8CollectHistogram(src, it->yuv_p_ + VP8I4ModeOffsets[mode],
0, 1, &histos[cur_histo]);
alpha = GetAlpha(&histos[cur_histo]);
if (IS_BETTER_ALPHA(alpha, best_mode_alpha)) {
best_mode_alpha = alpha;
modes[it->i4_] = mode;
cur_histo ^= 1; // keep track of best histo so far.
}
}
// accumulate best histogram
MergeHistograms(&histos[cur_histo ^ 1], &total_histo);
// Note: we reuse the original samples for predictors
} while (VP8IteratorRotateI4(it, it->yuv_in_ + Y_OFF_ENC));
i4_alpha = GetAlpha(&total_histo);
if (IS_BETTER_ALPHA(i4_alpha, best_alpha)) {
VP8SetIntra4Mode(it, modes);
best_alpha = i4_alpha;
}
return best_alpha;
}
static int MBAnalyzeBestUVMode(VP8EncIterator* const it) {
int best_alpha = DEFAULT_ALPHA;
int smallest_alpha = 0;
@ -371,13 +318,6 @@ static void MBAnalyze(VP8EncIterator* const it,
best_alpha = FastMBAnalyze(it);
} else {
best_alpha = MBAnalyzeBestIntra16Mode(it);
if (enc->method_ >= 5) {
// We go and make a fast decision for intra4/intra16.
// It's usually not a good and definitive pick, but helps seeding the
// stats about level bit-cost.
// TODO(skal): improve criterion.
best_alpha = MBAnalyzeBestIntra4Mode(it, best_alpha);
}
}
best_uv_alpha = MBAnalyzeBestUVMode(it);