Commit 507c8342 authored by Fiona Glaser's avatar Fiona Glaser

Add row-based VBV for B-frames

While B-frames still aren't explicitly covered by ratecontrol, this should resolve issues of VBV underflows due to larger-than-expected B-frames.
parent c51d00b7
......@@ -1038,7 +1038,7 @@ static double predict_row_size( x264_t *h, int y, int qp )
double pred_t = 0;
if( h->sh.i_type == SLICE_TYPE_I || qp >= h->fref0[0]->i_row_qp[y] )
{
if( h->sh.i_type != SLICE_TYPE_I
if( h->sh.i_type == SLICE_TYPE_P
&& h->fref0[0]->i_type == h->fdec->i_type
&& h->fref0[0]->i_row_satd[y] > 0
&& (abs(h->fref0[0]->i_row_satd[y] - h->fdec->i_row_satd[y]) < h->fdec->i_row_satd[y]/2))
......@@ -1096,89 +1096,75 @@ void x264_ratecontrol_mb( x264_t *h, int bits )
h->fdec->i_row_qp[y] = rc->qpm;
if( h->sh.i_type == SLICE_TYPE_B )
update_predictor( rc->row_pred[0], qp2qscale(rc->qpm), h->fdec->i_row_satd[y], h->fdec->i_row_bits[y] );
if( h->sh.i_type == SLICE_TYPE_P && rc->qpm < h->fref0[0]->i_row_qp[y] )
{
/* B-frames shouldn't use lower QP than their reference frames.
* This code is a bit overzealous in limiting B-frame quantizers, but it helps avoid
* underflows due to the fact that B-frames are not explicitly covered by VBV. */
if( y < h->sps->i_mb_height-1 )
{
int i_estimated;
int avg_qp = X264_MIN(h->fref0[0]->i_row_qp[y+1], h->fref1[0]->i_row_qp[y+1])
+ rc->pb_offset * ((h->fenc->i_type == X264_TYPE_BREF) ? 0.5 : 1);
rc->qpm = X264_MIN(X264_MAX( rc->qp, avg_qp), 51); //avg_qp could go higher than 51 due to pb_offset
i_estimated = row_bits_so_far(h, y); //FIXME: compute full estimated size
if (i_estimated > h->rc->frame_size_planned)
x264_ratecontrol_set_estimated_size(h, i_estimated);
}
double newq = qp2qscale(rc->qpm);
double oldq = qp2qscale(h->fref0[0]->i_row_qp[y]);
update_predictor( rc->row_pred[1], (1 - newq / oldq) * newq, h->fdec->i_row_satds[0][0][y], h->fdec->i_row_bits[y] );
}
else
/* tweak quality based on difference from predicted size */
if( y < h->sps->i_mb_height-1 )
{
update_predictor( rc->row_pred[0], qp2qscale(rc->qpm), h->fdec->i_row_satd[y], h->fdec->i_row_bits[y] );
if( h->sh.i_type != SLICE_TYPE_I && rc->qpm < h->fref0[0]->i_row_qp[y] )
int prev_row_qp = h->fdec->i_row_qp[y];
int b0 = predict_row_size_sum( h, y, rc->qpm );
int b1 = b0;
int i_qp_max = X264_MIN( prev_row_qp + h->param.rc.i_qp_step, h->param.rc.i_qp_max );
int i_qp_min = X264_MAX( prev_row_qp - h->param.rc.i_qp_step, h->param.rc.i_qp_min );
float buffer_left_planned = rc->buffer_fill - rc->frame_size_planned;
/* B-frames shouldn't use lower QP than their reference frames. */
if( h->sh.i_type == SLICE_TYPE_B )
i_qp_min = X264_MAX( i_qp_min, X264_MIN( h->fref0[0]->i_row_qp[y+1], h->fref1[0]->i_row_qp[y+1] ) );
/* More threads means we have to be more cautious in letting ratecontrol use up extra bits.
* In 2-pass mode we can be more trusting of the planned frame sizes, since they were decided
* by actual encoding instead of SATD prediction. */
float rc_tol = buffer_left_planned / h->param.i_threads * rc->rate_tolerance;
if( h->param.rc.b_stat_read )
rc_tol *= rc->frame_size_planned / rc->buffer_size;
/* Don't modify the row QPs until a sufficent amount of the bits of the frame have been processed, in case a flat */
/* area at the top of the frame was measured inaccurately. */
if( row_bits_so_far(h,y) < 0.05 * rc->frame_size_planned )
return;
if( h->sh.i_type != SLICE_TYPE_I )
rc_tol /= 2;
if( !rc->b_vbv_min_rate )
i_qp_min = X264_MAX( i_qp_min, h->sh.i_qp );
while( rc->qpm < i_qp_max
&& ((b1 > rc->frame_size_planned + rc_tol) ||
(rc->buffer_fill - b1 < buffer_left_planned * 0.5) ||
(b1 > rc->frame_size_planned && rc->qpm < rc->qp_novbv)) )
{
double newq = qp2qscale(rc->qpm);
double oldq = qp2qscale(h->fref0[0]->i_row_qp[y]);
update_predictor( rc->row_pred[1], (1 - newq / oldq) * newq, h->fdec->i_row_satds[0][0][y], h->fdec->i_row_bits[y] );
rc->qpm ++;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
/* tweak quality based on difference from predicted size */
if( y < h->sps->i_mb_height-1 )// && h->stat.i_frame_count[h->sh.i_type] > 0 )
while( rc->qpm > i_qp_min
&& (rc->qpm > h->fdec->i_row_qp[0] || rc->single_frame_vbv)
&& ((b1 < rc->frame_size_planned * 0.8 && rc->qpm <= prev_row_qp)
|| b1 < (rc->buffer_fill - rc->buffer_size + rc->buffer_rate) * 1.1) )
{
int prev_row_qp = h->fdec->i_row_qp[y];
int b0 = predict_row_size_sum( h, y, rc->qpm );
int b1 = b0;
int i_qp_max = X264_MIN( prev_row_qp + h->param.rc.i_qp_step, h->param.rc.i_qp_max );
int i_qp_min = X264_MAX( prev_row_qp - h->param.rc.i_qp_step, h->param.rc.i_qp_min );
float buffer_left_planned = rc->buffer_fill - rc->frame_size_planned;
/* More threads means we have to be more cautious in letting ratecontrol use up extra bits.
* In 2-pass mode we can be more trusting of the planned frame sizes, since they were decided
* by actual encoding instead of SATD prediction. */
float rc_tol = buffer_left_planned / h->param.i_threads * rc->rate_tolerance;
if( h->param.rc.b_stat_read )
rc_tol *= rc->frame_size_planned / rc->buffer_size;
/* Don't modify the row QPs until a sufficent amount of the bits of the frame have been processed, in case a flat */
/* area at the top of the frame was measured inaccurately. */
if( row_bits_so_far(h,y) < 0.05 * rc->frame_size_planned )
return;
if(h->sh.i_type != SLICE_TYPE_I)
rc_tol /= 2;
if( !rc->b_vbv_min_rate )
i_qp_min = X264_MAX( i_qp_min, h->sh.i_qp );
while( rc->qpm < i_qp_max
&& ((b1 > rc->frame_size_planned + rc_tol) ||
(rc->buffer_fill - b1 < buffer_left_planned * 0.5) ||
(b1 > rc->frame_size_planned && rc->qpm < rc->qp_novbv)) )
{
rc->qpm ++;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
while( rc->qpm > i_qp_min
&& (rc->qpm > h->fdec->i_row_qp[0] || rc->single_frame_vbv)
&& ((b1 < rc->frame_size_planned * 0.8 && rc->qpm <= prev_row_qp)
|| b1 < (rc->buffer_fill - rc->buffer_size + rc->buffer_rate) * 1.1) )
{
rc->qpm --;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
/* avoid VBV underflow */
while( (rc->qpm < h->param.rc.i_qp_max)
&& (rc->buffer_fill - b1 < rc->buffer_rate * 0.05 ) )
{
rc->qpm ++;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
rc->qpm --;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
x264_ratecontrol_set_estimated_size(h, b1);
/* avoid VBV underflow */
while( (rc->qpm < h->param.rc.i_qp_max)
&& (rc->buffer_fill - b1 < rc->buffer_rate * 0.05 ) )
{
rc->qpm ++;
b1 = predict_row_size_sum( h, y, rc->qpm );
}
x264_ratecontrol_set_estimated_size(h, b1);
}
/* loses the fractional part of the frame-wise qp */
rc->f_qpm = rc->qpm;
}
......@@ -1712,7 +1698,9 @@ static float rate_estimate_qscale( x264_t *h )
rcc->frame_size_planned = predict_size( rcc->pred_b_from_p, q, h->fref1[h->i_ref1-1]->i_satd );
x264_ratecontrol_set_estimated_size(h, rcc->frame_size_planned);
rcc->last_satd = 0;
/* For row SATDs */
if( rcc->b_vbv )
rcc->last_satd = x264_rc_analyse_slice( h );
return qp2qscale(q);
}
else
......@@ -1781,7 +1769,7 @@ static float rate_estimate_qscale( x264_t *h )
expected_size = qscale2bits(&rce, q);
expected_vbv = rcc->buffer_fill + rcc->buffer_rate - expected_size;
}
rcc->last_satd = x264_stack_align( x264_rc_analyse_slice, h );
rcc->last_satd = x264_rc_analyse_slice( h );
}
q = x264_clip3f( q, lmin, lmax );
}
......@@ -1799,7 +1787,7 @@ static float rate_estimate_qscale( x264_t *h )
double wanted_bits, overflow=1, lmin, lmax;
rcc->last_satd = x264_stack_align( x264_rc_analyse_slice, h );
rcc->last_satd = x264_rc_analyse_slice( h );
rcc->short_term_cplxsum *= 0.5;
rcc->short_term_cplxcount *= 0.5;
rcc->short_term_cplxsum += rcc->last_satd;
......
......@@ -997,9 +997,19 @@ void x264_slicetype_decide( x264_t *h )
x264_slicetype_frame_cost( h, &a, frames, p0, p1, b, 0 );
/* We need the intra costs for row SATDs. */
if( b && h->param.rc.i_vbv_buffer_size )
{
/* We need the intra costs for row SATDs. */
x264_slicetype_frame_cost( h, &a, frames, b, b, b, 0 );
/* We need B-frame costs for row SATDs. */
for( i = 0; i < bframes; i++ )
{
b = bframes - i;
frames[b] = h->lookahead->next.list[i];
x264_slicetype_frame_cost( h, &a, frames, p0, p1, b, 0 );
}
}
}
}
......@@ -1011,8 +1021,14 @@ int x264_rc_analyse_slice( x264_t *h )
if( IS_X264_TYPE_I(h->fenc->i_type) )
p1 = b = 0;
else // P
else if( h->fenc->i_type == X264_TYPE_P )
p1 = b = h->fenc->i_bframes + 1;
else //B
{
p1 = (h->fref1[0]->i_poc - h->fref0[0]->i_poc)/2;
b = (h->fref1[0]->i_poc - h->fenc->i_poc)/2;
frames[p1] = h->fref1[0];
}
frames[p0] = h->fref0[0];
frames[b] = h->fenc;
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment