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Improved key frame detection.

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In some cases where clips have been encoded with
borders (eg. some wide-screen content where there is a
border top and bottom and slide shows containing portrait
format photographs (border left and right)) key frames were
not being correctly detected.

The new code looks to measure cases where a portion of
the image can be coded equally easily using intra or inter
modes and where the resulting error score is also very low.
These "neutral" areas are then discounted in the key frame
detection code.

Change-Id: I00c3e8230772b8213cdc08020e1990cf83b780d8
This commit is contained in:
Paul Wilkins 2011-03-07 15:58:07 +00:00
parent 9fc8cb39aa
commit bc9c30a003
2 changed files with 28 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

31
vp8/encoder/firstpass.c
View File

@ -312,7 +312,9 @@ void vp8_output_stats(const VP8_COMP *cpi,
FILE *fpfile;
fpfile = fopen("firstpass.stt", "a");
fprintf(fpfile, "%12.0f %12.0f %12.0f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.0f\n",
fprintf(fpfile, "%12.0f %12.0f %12.0f %12.4f %12.4f %12.4f %12.4f
%12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.0f
%12.4f\n",
stats->frame,
stats->intra_error,
stats->coded_error,
@ -320,6 +322,7 @@ void vp8_output_stats(const VP8_COMP *cpi,
stats->pcnt_inter,
stats->pcnt_motion,
stats->pcnt_second_ref,
stats->pcnt_neutral,
stats->MVr,
stats->mvr_abs,
stats->MVc,
@ -327,7 +330,8 @@ void vp8_output_stats(const VP8_COMP *cpi,
stats->MVrv,
stats->MVcv,
stats->mv_in_out_count,
stats->count);
stats->count,
stats->duration);
fclose(fpfile);
@ -359,6 +363,7 @@ void vp8_zero_stats(FIRSTPASS_STATS *section)
section->pcnt_inter = 0.0;
section->pcnt_motion = 0.0;
section->pcnt_second_ref = 0.0;
section->pcnt_neutral = 0.0;
section->MVr = 0.0;
section->mvr_abs = 0.0;
section->MVc = 0.0;
@ -378,6 +383,7 @@ void vp8_accumulate_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame)
section->pcnt_inter += frame->pcnt_inter;
section->pcnt_motion += frame->pcnt_motion;
section->pcnt_second_ref += frame->pcnt_second_ref;
section->pcnt_neutral += frame->pcnt_neutral;
section->MVr += frame->MVr;
section->mvr_abs += frame->mvr_abs;
section->MVc += frame->MVc;
@ -398,6 +404,7 @@ void vp8_avg_stats(FIRSTPASS_STATS *section)
section->ssim_weighted_pred_err /= section->count;
section->pcnt_inter /= section->count;
section->pcnt_second_ref /= section->count;
section->pcnt_neutral /= section->count;
section->pcnt_motion /= section->count;
section->MVr /= section->count;
section->mvr_abs /= section->count;
@ -570,6 +577,7 @@ void vp8_first_pass(VP8_COMP *cpi)
int intercount = 0;
int second_ref_count = 0;
int intrapenalty = 256;
int neutral_count = 0;
int sum_in_vectors = 0;
@ -726,6 +734,17 @@ void vp8_first_pass(VP8_COMP *cpi)
if (motion_error <= this_error)
{
// Keep a count of cases where the inter and intra were
// very close and very low. This helps with scene cut
// detection for example in cropped clips with black bars
// at the sides or top and bottom.
if( (((this_error-intrapenalty) * 9) <=
(motion_error*10)) &&
(this_error < (2*intrapenalty)) )
{
neutral_count++;
}
d->bmi.mv.as_mv.row <<= 3;
d->bmi.mv.as_mv.col <<= 3;
this_error = motion_error;
@ -854,6 +873,7 @@ void vp8_first_pass(VP8_COMP *cpi)
fps.pcnt_inter = 1.0 * (double)intercount / cm->MBs;
fps.pcnt_second_ref = 1.0 * (double)second_ref_count / cm->MBs;
fps.pcnt_neutral = 1.0 * (double)neutral_count / cm->MBs;
if (mvcount > 0)
{
@ -1375,6 +1395,7 @@ double get_prediction_decay_rate(VP8_COMP *cpi, FIRSTPASS_STATS *next_frame)
return prediction_decay_rate;
}
// Funtion to test for a condition where a complex transition is followe
// by a static section. For example in slide shows where there is a fade
// between slides. This is to help with more optimal kf and gf positioning.
@ -2295,7 +2316,7 @@ static BOOL test_candidate_kf(VP8_COMP *cpi, FIRSTPASS_STATS *last_frame, FIRST
(next_frame->pcnt_second_ref < 0.10) &&
((this_frame->pcnt_inter < 0.05) ||
(
(this_frame->pcnt_inter < .25) &&
((this_frame->pcnt_inter - this_frame->pcnt_neutral) < .25) &&
((this_frame->intra_error / DOUBLE_DIVIDE_CHECK(this_frame->coded_error)) < 2.5) &&
((fabs(last_frame->coded_error - this_frame->coded_error) / DOUBLE_DIVIDE_CHECK(this_frame->coded_error) > .40) ||
(fabs(last_frame->intra_error - this_frame->intra_error) / DOUBLE_DIVIDE_CHECK(this_frame->intra_error) > .40) ||
@ -2342,7 +2363,9 @@ static BOOL test_candidate_kf(VP8_COMP *cpi, FIRSTPASS_STATS *last_frame, FIRST
// Test various breakout clauses
if ((local_next_frame.pcnt_inter < 0.05) ||
(next_iiratio < 1.5) ||
((local_next_frame.pcnt_inter < 0.20) && (next_iiratio < 3.0)) ||
(((local_next_frame.pcnt_inter -
local_next_frame.pcnt_neutral) < 0.20) &&
(next_iiratio < 3.0)) ||
((boost_score - old_boost_score) < 0.5) ||
(local_next_frame.intra_error < 200)
)

1
vp8/encoder/onyx_int.h
View File

@ -99,6 +99,7 @@ typedef struct
double pcnt_inter;
double pcnt_motion;
double pcnt_second_ref;
double pcnt_neutral;
double MVr;
double mvr_abs;
double MVc;