shithub: libvpx

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Add a method to estimate loop filter level from quantizer and frame type.

Use this method with rt at speed -5.

Change-Id: If3bd6fad4c05ddde72131442dad191e4145047e7

--- a/vp9/encoder/vp9_onyx_if.c

+++ b/vp9/encoder/vp9_onyx_if.c

@@ -851,6 +851,7 @@

       sf->intra_y_mode_mask[i] = INTRA_DC_H_V;

       sf->intra_uv_mode_mask[i] = INTRA_DC_ONLY;

     }

+    sf->use_fast_lpf_pick = 2;

   }

 }

--- a/vp9/encoder/vp9_onyx_int.h

+++ b/vp9/encoder/vp9_onyx_int.h

@@ -409,8 +409,10 @@

   // final encode.

   int use_uv_intra_rd_estimate;

-  // This picks a loop filter strength by trying a small portion of the image

-  // with different values.

+  // This feature controls how the loop filter level is determined:

+  // 0: Try the full image with different values.

+  // 1: Try a small portion of the image with different values.

+  // 2: Estimate the level based on quantizer and frame type

   int use_fast_lpf_pick;

   // This feature limits the number of coefficients updates we actually do

--- a/vp9/encoder/vp9_picklpf.c

+++ b/vp9/encoder/vp9_picklpf.c

@@ -14,6 +14,7 @@

 #include "vp9/encoder/vp9_onyx_int.h"

 #include "vp9/encoder/vp9_picklpf.h"

 #include "vp9/encoder/vp9_quantize.h"

+#include "vp9/common/vp9_quant_common.h"

 #include "vpx_mem/vpx_mem.h"

 #include "vpx_scale/vpx_scale.h"

 #include "vp9/common/vp9_alloccommon.h"

@@ -33,7 +34,8 @@

 void vp9_set_alt_lf_level(VP9_COMP *cpi, int filt_val) {

 }

-void vp9_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi, int partial) {

+static void search_filter_level(YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi,

+                                int partial) {

   MACROBLOCKD *const xd = &cpi->mb.e_mbd;

   VP9_COMMON *const cm = &cpi->common;

   struct loopfilter *const lf = &cm->lf;

@@ -48,9 +50,6 @@

   int filt_mid = clamp(lf->filter_level, min_filter_level, max_filter_level);

   int filter_step = filt_mid < 16 ? 4 : filt_mid / 4;

-  lf->sharpness_level = cm->frame_type == KEY_FRAME ? 0

-                                                    : cpi->oxcf.sharpness;

-

   //  Make a copy of the unfiltered / processed recon buffer

   vpx_yv12_copy_y(cm->frame_to_show, &cpi->last_frame_uf);

@@ -127,4 +126,27 @@

   }

   lf->filter_level = filt_best;

+}

+

+void vp9_pick_filter_level(YV12_BUFFER_CONFIG *sd, VP9_COMP *cpi, int method) {

+  VP9_COMMON *const cm = &cpi->common;

+  struct loopfilter *const lf = &cm->lf;

+

+  lf->sharpness_level = cm->frame_type == KEY_FRAME ? 0

+                                                    : cpi->oxcf.sharpness;

+

+  if (method == 2) {

+    const int min_filter_level = get_min_filter_level(cpi, cm->base_qindex);

+    const int max_filter_level = get_max_filter_level(cpi, cm->base_qindex);

+    const int q = vp9_ac_quant(cm->base_qindex, 0);

+    // These values were determined by linear fitting the result of the

+    // searched level

+    // filt_guess = q * 0.316206 + 3.87252

+    int filt_guess = (q * 20723 + 1015158 + (1 << 17)) >> 18;

+    if (cm->frame_type == KEY_FRAME)

+      filt_guess -= 4;

+    lf->filter_level = clamp(filt_guess, min_filter_level, max_filter_level);

+  } else {

+    search_filter_level(sd, cpi, method == 1);

+  }

 }

--- a/vp9/encoder/vp9_picklpf.h

+++ b/vp9/encoder/vp9_picklpf.h

@@ -22,7 +22,7 @@

 void vp9_set_alt_lf_level(struct VP9_COMP *cpi, int filt_val);

 void vp9_pick_filter_level(struct yv12_buffer_config *sd,

-                           struct VP9_COMP *cpi, int partial);

+                           struct VP9_COMP *cpi, int method);

 #ifdef __cplusplus

 }  // extern "C"

 #endif