generic-library/vpx
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Adjustment to VBR rate correction.

Browse Source 
Changes to the function the redistributes bits from overshoot
or undershoot throughout the rest of the clip to respond more
quickly.

Change-Id: I90f10900cdd82cf2ce1d8da4b6f91eb5934310da
This commit is contained in:
paulwilkins 2016-05-24 15:21:13 +01:00
parent cd700e1ab9
commit c7ac2f3864
1 changed files with 20 additions and 19 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
vp9/encoder/vp9_ratectrl.c
View File

@ -1889,27 +1889,28 @@ static void vbr_rate_correction(VP9_COMP *cpi, int *this_frame_target) {
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.