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Shorten GF/arf interval in hard scenes.

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This patch accounts in the first pass stats for blocks that
while not coded as intra, are complex and have an intra error /
best error ratio below a threshold.

The modification shortens the GF arf interval for a particular
class of content that contains a lot of blocks matching the
above criteria. (In one short problem test sequence the average
interval dropped from about 14-15 to 10-11)

The change results in small net gains in metrics results for the
Yt(~0.2%) and yt-hd (~0.5%) sets and is approximately neutral
for the other test sets.

The change is currently shielded by a flag and off by default
pending verification that it does not cause other regressions
in tests on a wider YT test set.

Change-Id: I6b803daa6a4ac09a6f428fb3a18be1ecedd974b7
This commit is contained in:
paulwilkins
2015-03-06 16:32:20 +00:00
parent b12f531cc5
commit b29c48b03c
1 changed files with 41 additions and 6 deletions
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47
vp9/encoder/vp9_firstpass.c
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@@ -60,6 +60,14 @@
#define RC_FACTOR_MIN 0.75
#define RC_FACTOR_MAX 1.75
#define INTRA_WEIGHT_EXPERIMENT 0
#if INTRA_WEIGHT_EXPERIMENT
#define NCOUNT_INTRA_THRESH 8192
#define NCOUNT_INTRA_FACTOR 3
#define NCOUNT_FRAME_II_THRESH 5.0
#endif
#define DOUBLE_DIVIDE_CHECK(x) ((x) < 0 ? (x) - 0.000001 : (x) + 0.000001)
#if ARF_STATS_OUTPUT
@@ -470,7 +478,7 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
int intercount = 0;
int second_ref_count = 0;
const int intrapenalty = INTRA_MODE_PENALTY;
int neutral_count = 0;
double neutral_count;
int new_mv_count = 0;
int sum_in_vectors = 0;
MV lastmv = {0, 0};
@@ -503,6 +511,7 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
intra_factor = 0.0;
brightness_factor = 0.0;
neutral_count = 0.0;
set_first_pass_params(cpi);
vp9_set_quantizer(cm, find_fp_qindex(cm->bit_depth));
@@ -818,12 +827,28 @@ void vp9_first_pass(VP9_COMP *cpi, const struct lookahead_entry *source) {
#endif
if (motion_error <= this_error) {
vp9_clear_system_state();
// Keep a count of cases where the inter and intra were very close
// and very low. This helps with scene cut detection for example in
// cropped clips with black bars at the sides or top and bottom.
#if INTRA_WEIGHT_EXPERIMENT
if (((this_error - intrapenalty) * 9 <= motion_error * 10) &&
this_error < 2 * intrapenalty)
++neutral_count;
(this_error < (2 * intrapenalty))) {
neutral_count += 1.0;
// Also track cases where the intra is not much worse than the inter
// and use this in limiting the GF/arf group length.
} else if ((this_error > NCOUNT_INTRA_THRESH) &&
(this_error < (NCOUNT_INTRA_FACTOR * motion_error))) {
neutral_count += (double)motion_error /
DOUBLE_DIVIDE_CHECK((double)this_error);
}
#else
if (((this_error - intrapenalty) * 9 <= motion_error * 10) &&
(this_error < (2 * intrapenalty))) {
neutral_count += 1.0;
}
#endif
mv.row *= 8;
mv.col *= 8;
@@ -1260,17 +1285,27 @@ static double get_sr_decay_rate(const VP9_COMP *cpi,
double sr_diff =
(frame->sr_coded_error - frame->coded_error) / num_mbs;
double sr_decay = 1.0;
double modified_pct_inter;
double modified_pcnt_intra;
const double motion_amplitude_factor =
frame->pcnt_motion * ((frame->mvc_abs + frame->mvr_abs) / 2);
const double pcnt_intra = 100 * (1.0 - frame->pcnt_inter);
modified_pct_inter = frame->pcnt_inter;
#if INTRA_WEIGHT_EXPERIMENT
if ((frame->intra_error / DOUBLE_DIVIDE_CHECK(frame->coded_error)) <
(double)NCOUNT_FRAME_II_THRESH)
modified_pct_inter = frame->pcnt_inter - frame->pcnt_neutral;
#endif
modified_pcnt_intra = 100 * (1.0 - modified_pct_inter);
if ((sr_diff > LOW_SR_DIFF_TRHESH)) {
sr_diff = MIN(sr_diff, SR_DIFF_MAX);
sr_decay = 1.0 - (SR_DIFF_PART * sr_diff) -
(MOTION_AMP_PART * motion_amplitude_factor) -
(INTRA_PART * pcnt_intra);
(INTRA_PART * modified_pcnt_intra);
}
return MAX(sr_decay, MIN(DEFAULT_DECAY_LIMIT, frame->pcnt_inter));
return MAX(sr_decay, MIN(DEFAULT_DECAY_LIMIT, modified_pct_inter));
}
// This function gives an estimate of how badly we believe the prediction