Commit 737179f2 authored by Yaowu Xu's avatar Yaowu Xu
Browse files

Reduced bias in picking loop filter level

The bias in picklpf intended to bias toward less greedy in getting
best frame level psnr while maximize overall quality for a clip.
This commit reduced the bias for frames using 8x8 transform to
achieve better compression overall.

The change improve compression by ~.15% consistently on most of the
HD clips tested.

http://www.corp.google.com/~yaowu/no_crawl/LPFBias_FixSkip.html

Change-Id: Ic30932d2b8eaebd52339b0195f569edc48eed7bc
parent 47d545f1
......@@ -354,6 +354,12 @@ void vp8cx_pick_filter_level_sg(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi, int segme
if (cpi->twopass.section_intra_rating < 20)
Bias = Bias * cpi->twopass.section_intra_rating / 20;
#if CONFIG_T8X8
// yx, bias less for large block size
if(cpi->common.txfm_mode == ALLOW_8X8)
Bias >>= 1;
#endif
filt_high = ((filt_mid + filter_step) > max_filter_level) ? max_filter_level : (filt_mid + filter_step);
filt_low = ((filt_mid - filter_step) < min_filter_level) ? min_filter_level : (filt_mid - filter_step);
......@@ -572,6 +578,12 @@ void vp8cx_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP8_COMP *cpi)
if (cpi->twopass.section_intra_rating < 20)
Bias = Bias * cpi->twopass.section_intra_rating / 20;
#if CONFIG_T8X8
// yx, bias less for large block size
if(cpi->common.txfm_mode == ALLOW_8X8)
Bias >>= 1;
#endif
filt_high = ((filt_mid + filter_step) > max_filter_level) ? max_filter_level : (filt_mid + filter_step);
filt_low = ((filt_mid - filter_step) < min_filter_level) ? min_filter_level : (filt_mid - filter_step);
......
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