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Modified static scene check.

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Added code to scan ahead a few frames when we see what
we think is a static scene in the two pass GF loop to see if the
conditions persist.

Moved calculation of decay rate out into a fuunction.

Change-Id: I6e9c67e01ec9f555144deafc8ae67ef25bffb449
This commit is contained in:
Paul Wilkins 2011-01-21 17:52:00 +00:00
parent 8064583d26
commit 0cdfef1e22
1 changed files with 73 additions and 30 deletions
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103
vp8/encoder/firstpass.c
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@ -1316,6 +1316,43 @@ void vp8_end_second_pass(VP8_COMP *cpi)
{
}
// This function gives and estimate of how badly we believe
// the predicition quality is decaying from frame to frame.
double gf_prediction_decay_rate(VP8_COMP *cpi, FIRSTPASS_STATS *next_frame)
{
double prediction_decay_rate;
double motion_decay;
double motion_pct = next_frame->pcnt_motion;
// Initial basis is the % mbs inter coded
prediction_decay_rate = next_frame->pcnt_inter;
// High % motion -> somewhat higher decay rate
motion_decay = (1.0 - (motion_pct / 20.0));
if (motion_decay < prediction_decay_rate)
prediction_decay_rate = motion_decay;
// Adjustment to decay rate based on speed of motion
{
double this_mv_rabs;
double this_mv_cabs;
double distance_factor;
this_mv_rabs = fabs(next_frame->mvr_abs * motion_pct);
this_mv_cabs = fabs(next_frame->mvc_abs * motion_pct);
distance_factor = sqrt((this_mv_rabs * this_mv_rabs) +
(this_mv_cabs * this_mv_cabs)) / 250.0;
distance_factor = ((distance_factor > 1.0)
? 0.0 : (1.0 - distance_factor));
if (distance_factor < prediction_decay_rate)
prediction_decay_rate = distance_factor;
}
return prediction_decay_rate;
}
// Analyse and define a gf/arf group .
static void define_gf_group(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
{
@ -1468,36 +1505,11 @@ static void define_gf_group(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
if (r > GF_RMAX)
r = GF_RMAX;
// Adjust loop decay rate
//if ( next_frame.pcnt_inter < loop_decay_rate )
loop_decay_rate = next_frame.pcnt_inter;
// High % motion -> somewhat higher decay rate
motion_decay = (1.0 - (motion_pct / 20.0));
if (motion_decay < loop_decay_rate)
loop_decay_rate = motion_decay;
// Adjustment to decay rate based on speed of motion
{
double this_mv_rabs;
double this_mv_cabs;
double distance_factor;
this_mv_rabs = fabs(next_frame.mvr_abs * motion_pct);
this_mv_cabs = fabs(next_frame.mvc_abs * motion_pct);
distance_factor = sqrt((this_mv_rabs * this_mv_rabs) +
(this_mv_cabs * this_mv_cabs)) / 250.0;
distance_factor = ((distance_factor > 1.0)
? 0.0 : (1.0 - distance_factor));
if (distance_factor < loop_decay_rate)
loop_decay_rate = distance_factor;
}
loop_decay_rate = gf_prediction_decay_rate(cpi, &next_frame);
// Cumulative effect of decay
decay_accumulator = decay_accumulator * loop_decay_rate;
decay_accumulator = decay_accumulator < 0.1 ? 0.1 : decay_accumulator;
//decay_accumulator = ( loop_decay_rate < decay_accumulator ) ? loop_decay_rate : decay_accumulator;
boost_score += (decay_accumulator * r);
@ -1508,11 +1520,42 @@ static void define_gf_group(VP8_COMP *cpi, FIRSTPASS_STATS *this_frame)
(loop_decay_rate >= 0.999) &&
(decay_accumulator < 0.9) )
{
// Force GF not alt ref
allow_alt_ref = FALSE;
int j;
FIRSTPASS_STATS * position = cpi->stats_in;
FIRSTPASS_STATS tmp_next_frame;
double decay_rate;
boost_score = old_boost_score;
break;
// Look ahead a few frames to see if static condition
// persists...
for ( j = 0; j < 4; j++ )
{
if (EOF == vp8_input_stats(cpi, &tmp_next_frame))
break;
decay_rate = gf_prediction_decay_rate(cpi, &tmp_next_frame);
if ( decay_rate < 0.999 )
break;
}
reset_fpf_position(cpi, position); // Reset file position
// Force GF not alt ref
if ( j == 4 )
{
if (0)
{
FILE *f = fopen("fadegf.stt", "a");
fprintf(f, " %8d %8d %10.4f %10.4f %10.4f\n",
cpi->common.current_video_frame+i, i,
loop_decay_rate, decay_accumulator,
boost_score );
fclose(f);
}
allow_alt_ref = FALSE;
boost_score = old_boost_score;
break;
}
}
// Break out conditions.