ref: c7ac2f38643a31c48109cb81720b4b54b684ccfd
parent: cd700e1ab919ca098bf78875d3a7326d91daa34d
author: paulwilkins <[email protected]>
date: Tue May 24 11:21:13 EDT 2016
Adjustment to VBR rate correction. Changes to the function the redistributes bits from overshoot or undershoot throughout the rest of the clip to respond more quickly. Change-Id: I90f10900cdd82cf2ce1d8da4b6f91eb5934310da
--- a/vp9/encoder/vp9_ratectrl.c
+++ b/vp9/encoder/vp9_ratectrl.c
@@ -1889,27 +1889,28 @@
RATE_CONTROL *const rc = &cpi->rc;
int64_t vbr_bits_off_target = rc->vbr_bits_off_target;
int max_delta;
- double position_factor = 1.0;
+ int frame_window = VPXMIN(16,
+ ((int)cpi->twopass.total_stats.count - cpi->common.current_video_frame));
- // How far through the clip are we.
- // This number is used to damp the per frame rate correction.
- // Range 0 - 1.0
- if (cpi->twopass.total_stats.count) {- position_factor = sqrt((double)cpi->common.current_video_frame /
- cpi->twopass.total_stats.count);
- }
- max_delta = (int)(position_factor *
- ((*this_frame_target * VBR_PCT_ADJUSTMENT_LIMIT) / 100));
+ // Calcluate the adjustment to rate for this frame.
+ if (frame_window > 0) {+ max_delta = (vbr_bits_off_target > 0)
+ ? (int)(vbr_bits_off_target / frame_window)
+ : (int)(-vbr_bits_off_target / frame_window);
- // vbr_bits_off_target > 0 means we have extra bits to spend
- if (vbr_bits_off_target > 0) {- *this_frame_target +=
- (vbr_bits_off_target > max_delta) ? max_delta
- : (int)vbr_bits_off_target;
- } else {- *this_frame_target -=
- (vbr_bits_off_target < -max_delta) ? max_delta
- : (int)-vbr_bits_off_target;
+ max_delta = VPXMIN(max_delta,
+ ((*this_frame_target * VBR_PCT_ADJUSTMENT_LIMIT) / 100));
+
+ // vbr_bits_off_target > 0 means we have extra bits to spend
+ if (vbr_bits_off_target > 0) {+ *this_frame_target +=
+ (vbr_bits_off_target > max_delta) ? max_delta
+ : (int)vbr_bits_off_target;
+ } else {+ *this_frame_target -=
+ (vbr_bits_off_target < -max_delta) ? max_delta
+ : (int)-vbr_bits_off_target;
+ }
}
// Fast redistribution of bits arising from massive local undershoot.