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Speed-up recode loop for extreme bitrate diffs

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Adjusts the q adjustement step depending on how far the
projected and target rates differ.

Change-Id: I498d03523ca233a270512ca3972c372daa4ca2a8
This commit is contained in:
Debargha Mukherjee 2016-10-27 09:55:36 -07:00
parent f53d3363ac
commit 1cd987d922
1 changed files with 16 additions and 2 deletions
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18
vp9/encoder/vp9_encoder.c
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@ -3216,6 +3216,13 @@ static void encode_without_recode_loop(VP9_COMP *cpi, size_t *size,
vpx_clear_system_state();
}
#define MAX_QSTEP_ADJ 4
static int get_qstep_adj(int rate_excess, int rate_limit) {
int qstep =
rate_limit ? ((rate_excess + rate_limit / 2) / rate_limit) : INT_MAX;
return VPXMIN(qstep, MAX_QSTEP_ADJ);
}
static void encode_with_recode_loop(VP9_COMP *cpi, size_t *size,
uint8_t *dest) {
VP9_COMMON *const cm = &cpi->common;
@ -3389,6 +3396,7 @@ static void encode_with_recode_loop(VP9_COMP *cpi, size_t *size,
// to attempt to recode.
int last_q = q;
int retries = 0;
int qstep;
if (cpi->resize_pending == 1) {
// Change in frame size so go back around the recode loop.
@ -3414,7 +3422,10 @@ static void encode_with_recode_loop(VP9_COMP *cpi, size_t *size,
q_high = rc->worst_quality;
// Raise Qlow as to at least the current value
q_low = q < q_high ? q + 1 : q_high;
qstep =
get_qstep_adj(rc->projected_frame_size, rc->this_frame_target);
q_low = VPXMIN(q + qstep, q_high);
// q_low = q < q_high ? q + 1 : q_high;
if (undershoot_seen || loop_at_this_size > 1) {
// Update rate_correction_factor unless
@ -3439,7 +3450,10 @@ static void encode_with_recode_loop(VP9_COMP *cpi, size_t *size,
overshoot_seen = 1;
} else {
// Frame is too small
q_high = q > q_low ? q - 1 : q_low;
qstep =
get_qstep_adj(rc->this_frame_target, rc->projected_frame_size);
q_high = VPXMAX(q - qstep, q_low);
// q_high = q > q_low ? q - 1 : q_low;
if (overshoot_seen || loop_at_this_size > 1) {
vp9_rc_update_rate_correction_factors(cpi);