Adjust gop shrinking for 32 length.
This patch adds various adjustments to better work with the 32
length gop:
1: change the logic when using tpl to determine longer or shorter
gop. If decided to use longer, or lag-in-frames is not
sufficient, we can still benefit from lookahead and lookback.
2: fix a problem of coded error lookup when we do not start with
a key frame in the current gf group. This way the padding is
also available to gf groups that are decided individually.
3: change the minimum shrinking length to 6, in order to benefit
individually determined gf groups.
4: now if user decides to restrain the max length to 16, we should
have a better performance.
On lag-in-frames=35, we have some minor gains on average:
test results (BD-rate, %) on speed 1:
avg_PSNR overall_PSNR ssim VMAF
lowres -0.007 -0.017 -0.017 -0.124
midres 0.016 0.074 0.194 -0.025
hdres -0.059 -0.068 -0.096 -0.065
ugc360p -0.134 -0.055 -0.064 -0.132
on speed 4:
avg_PSNR overall_PSNR ssim VMAF
lowres -0.078 -0.081 -0.056 -0.092
midres -0.021 0.041 0.131 -0.065
hdres -0.004 -0.014 -0.079 -0.060
ugc360p -0.206 -0.209 -0.247 -0.229
most gains in ugc360p, where it is not very stable and padding
could help most.
Changes on other test sets are small.
STATS_CHANGED
Change-Id: Ia43ff93a1a1943e53856f3109e1b0e476b9f3016
diff --git a/av1/encoder/pass2_strategy.c b/av1/encoder/pass2_strategy.c
index 2f20f45..6a4e20c 100644
--- a/av1/encoder/pass2_strategy.c
+++ b/av1/encoder/pass2_strategy.c
@@ -962,7 +962,7 @@
#define RC_FACTOR_MAX 1.25
#endif // GROUP_ADAPTIVE_MAXQ
#define MIN_FWD_KF_INTERVAL 8
-#define MIN_SHRINK_LEN 8 // the minimum length of gf if we are shrinking
+#define MIN_SHRINK_LEN 6 // the minimum length of gf if we are shrinking
#define SI_HIGH AVG_SI_THRES // high quality classification
#define SI_LOW 0.3 // very unsure classification
// this function finds an low error frame previously to the current last frame
@@ -1049,7 +1049,8 @@
// This function decides the gf group length of future frames in batch
// rc->gf_intervals is modified to store the group lengths
-static void calculate_gf_length(AV1_COMP *cpi, int max_gop_length) {
+static void calculate_gf_length(AV1_COMP *cpi, int max_gop_length,
+ int max_intervals) {
RATE_CONTROL *const rc = &cpi->rc;
TWO_PASS *const twopass = &cpi->twopass;
FIRSTPASS_STATS next_frame;
@@ -1072,11 +1073,11 @@
av1_zero(next_frame);
if (has_no_stats_stage(cpi)) {
- for (i = 0; i < NUM_GF_INTERVALS; i++) {
+ for (i = 0; i < MAX_NUM_GF_INTERVALS; i++) {
rc->gf_intervals[i] = MAX_GF_INTERVAL;
}
rc->cur_gf_index = 0;
- rc->intervals_till_gf_calculate_due = NUM_GF_INTERVALS;
+ rc->intervals_till_gf_calculate_due = MAX_NUM_GF_INTERVALS;
return;
}
@@ -1086,8 +1087,8 @@
AOMMIN(rc->max_gf_interval, max_gop_length);
i = 0;
- const int max_intervals = cpi->lap_enabled ? 1 : NUM_GF_INTERVALS;
- int cut_pos[NUM_GF_INTERVALS + 1] = { 0 };
+ max_intervals = cpi->lap_enabled ? 1 : max_intervals;
+ int cut_pos[MAX_NUM_GF_INTERVALS + 1] = { 0 };
int count_cuts = 1;
int cur_start = 0, cur_last;
int cut_here;
@@ -1150,7 +1151,8 @@
int is_high[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 };
double errs[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 };
double si[MAX_GF_INTERVAL + 1 + MAX_PAD_GF_CHECK * 2] = { 0 };
- int before_pad = AOMMIN(MAX_PAD_GF_CHECK, cur_start - (cur_start == 0));
+ int before_pad =
+ AOMMIN(MAX_PAD_GF_CHECK, rc->frames_since_key - 1 + cur_start);
int after_pad =
AOMMIN(MAX_PAD_GF_CHECK, rc->frames_to_key - cur_last - 1);
for (n = cur_start - before_pad; n <= cur_last + after_pad; n++) {
@@ -1170,7 +1172,7 @@
// count how many trailing lower error frames we have in this decided
// gf group
prev_lows = 0;
- for (n = cur_last; n > cur_start; n--) {
+ for (n = cur_last - 1; n > cur_start + MIN_SHRINK_LEN; n--) {
if (is_high[n - cur_start + before_pad] == 0 &&
(si[n - cur_start + before_pad] > SI_HIGH || reset)) {
prev_lows++;
@@ -1436,8 +1438,10 @@
}
*this_frame = next_frame;
}
- rc->intervals_till_gf_calculate_due--;
- rc->cur_gf_index++;
+ if (is_final_pass) {
+ rc->intervals_till_gf_calculate_due--;
+ rc->cur_gf_index++;
+ }
// Was the group length constrained by the requirement for a new KF?
rc->constrained_gf_group = (i >= rc->frames_to_key) ? 1 : 0;
@@ -1561,7 +1565,7 @@
if (i - roll_back >= active_min_gf_interval + 1) {
alt_offset = -roll_back;
i -= roll_back;
- rc->intervals_till_gf_calculate_due = 0;
+ if (is_final_pass) rc->intervals_till_gf_calculate_due = 0;
}
}
}
@@ -1601,12 +1605,12 @@
// if possible, merge the last two gf groups
if (rc->frames_to_key <= active_max_gf_interval) {
rc->baseline_gf_interval = rc->frames_to_key;
- rc->intervals_till_gf_calculate_due = 0;
+ if (is_final_pass) rc->intervals_till_gf_calculate_due = 0;
// if merging the last two gf groups creates a group that is too long,
// split them and force the last gf group to be the MIN_FWD_KF_INTERVAL
} else {
rc->baseline_gf_interval = rc->frames_to_key - MIN_FWD_KF_INTERVAL;
- rc->intervals_till_gf_calculate_due = 0;
+ if (is_final_pass) rc->intervals_till_gf_calculate_due = 0;
}
} else {
rc->baseline_gf_interval = i - rc->source_alt_ref_pending;
@@ -1619,7 +1623,7 @@
// the next gf group.
// TODO(bohanli): should incorporate the usage of alt_ref into
// calculate_gf_length
- if (rc->source_alt_ref_pending == 0 &&
+ if (is_final_pass && rc->source_alt_ref_pending == 0 &&
rc->intervals_till_gf_calculate_due > 0) {
rc->gf_intervals[rc->cur_gf_index]--;
}
@@ -2323,18 +2327,29 @@
if (rc->frames_till_gf_update_due == 0) {
assert(cpi->common.current_frame.frame_number == 0 ||
gf_group->index == gf_group->size);
- int max_gop_length = MAX_GF_INTERVAL;
- // TODO(jingning): Remove redundant computations here.
- if (cpi->oxcf.lag_in_frames >= 32) {
- calculate_gf_length(cpi, max_gop_length);
- define_gf_group(cpi, &this_frame, frame_params, max_gop_length, 0);
-
- if (!av1_tpl_setup_stats(cpi, 1, frame_params, frame_input))
- max_gop_length = 16;
- } else {
- max_gop_length = 16;
+ int max_gop_length = (cpi->oxcf.lag_in_frames >= 32) ? MAX_GF_INTERVAL : 16;
+ if (rc->intervals_till_gf_calculate_due == 0) {
+ calculate_gf_length(cpi, max_gop_length, MAX_NUM_GF_INTERVALS);
}
- calculate_gf_length(cpi, max_gop_length);
+
+ if (max_gop_length > 16) {
+ if (rc->gf_intervals[rc->cur_gf_index] - 1 > 16) {
+ // The calculate_gf_length function is previously used with
+ // max_gop_length = 32 with look-ahead gf intervals.
+ define_gf_group(cpi, &this_frame, frame_params, max_gop_length, 0);
+ if (!av1_tpl_setup_stats(cpi, 1, frame_params, frame_input)) {
+ // Tpl decides that a shorter gf interval is better.
+ // TODO(jingning): Remove redundant computations here.
+ max_gop_length = 16;
+ calculate_gf_length(cpi, max_gop_length, 1);
+ }
+ } else {
+ // Even based on 32 we still decide to use a short gf interval.
+ // Better to re-decide based on 16 then
+ max_gop_length = 16;
+ calculate_gf_length(cpi, max_gop_length, 1);
+ }
+ }
define_gf_group(cpi, &this_frame, frame_params, max_gop_length, 1);
rc->frames_till_gf_update_due = rc->baseline_gf_interval;
diff --git a/av1/encoder/ratectrl.h b/av1/encoder/ratectrl.h
index 61d58e4..038eac8 100644
--- a/av1/encoder/ratectrl.h
+++ b/av1/encoder/ratectrl.h
@@ -48,7 +48,7 @@
#define MAX_GF_INTERVAL 32
#define FIXED_GF_INTERVAL 8 // Used in some testing modes only
-#define NUM_GF_INTERVALS 150
+#define MAX_NUM_GF_INTERVALS 15
typedef struct {
int resize_width;
@@ -101,7 +101,7 @@
// number of determined gf group length left
int intervals_till_gf_calculate_due;
// stores gf group length intervals
- int gf_intervals[NUM_GF_INTERVALS];
+ int gf_intervals[MAX_NUM_GF_INTERVALS];
// the current index in gf_intervals
int cur_gf_index;
