shithub: libvpx

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Experiment to adapt for net AQ offset.

In Aq mode 1 the segment and AQ delta for each block is based
on spatial variance. There may be a net imbalance between blocks
that have lower Q than the baseline value and those that have higher Q.

This patch monitors that imbalance and extends the allowed baseline
Q range for the frame to accommodate adjustment of that baseline value
to compensate.

Change-Id: Iae8a48c7c01fe2af94a141e149d03acf467237ca

--- a/vp9/common/vp9_seg_common.c

+++ b/vp9/common/vp9_seg_common.c

@@ -28,6 +28,7 @@

 void vp9_clearall_segfeatures(struct segmentation *seg) {

   vp9_zero(seg->feature_data);

   vp9_zero(seg->feature_mask);

+  seg->aq_av_offset = 0;

 }

 void vp9_enable_segfeature(struct segmentation *seg, int segment_id,

--- a/vp9/common/vp9_seg_common.h

+++ b/vp9/common/vp9_seg_common.h

@@ -47,6 +47,7 @@

   int16_t feature_data[MAX_SEGMENTS][SEG_LVL_MAX];

   unsigned int feature_mask[MAX_SEGMENTS];

+  int aq_av_offset;

 };

 static INLINE int segfeature_active(const struct segmentation *seg,

--- a/vp9/encoder/vp9_encodeframe.c

+++ b/vp9/encoder/vp9_encodeframe.c

@@ -4137,6 +4137,31 @@

   }

 }

+static int compute_frame_aq_offset(struct VP9_COMP *cpi) {

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

+  MODE_INFO **mi_8x8_ptr = cm->mi_grid_visible;

+  struct segmentation *const seg = &cm->seg;

+

+  int mi_row, mi_col;

+  int sum_delta = 0;

+  int map_index = 0;

+  int qdelta_index;

+  int segment_id;

+

+  for (mi_row = 0; mi_row < cm->mi_rows; mi_row++) {

+    MODE_INFO **mi_8x8 = mi_8x8_ptr;

+    for (mi_col = 0; mi_col < cm->mi_cols; mi_col++, mi_8x8++) {

+      segment_id = mi_8x8[0]->segment_id;

+      qdelta_index = get_segdata(seg, segment_id, SEG_LVL_ALT_Q);

+      sum_delta += qdelta_index;

+      map_index++;

+    }

+    mi_8x8_ptr += cm->mi_stride;

+  }

+

+  return sum_delta / (cm->mi_rows * cm->mi_cols);

+}

+

 void vp9_encode_frame(VP9_COMP *cpi) {

   VP9_COMMON *const cm = &cpi->common;

@@ -4259,8 +4284,13 @@

     cm->reference_mode = SINGLE_REFERENCE;

     encode_frame_internal(cpi);

   }

-}

+  // If segmentated AQ is enabled compute the average AQ weighting.

+  if (cm->seg.enabled && (cpi->oxcf.aq_mode != NO_AQ) &&

+      (cm->seg.update_map || cm->seg.update_data)) {

+    cm->seg.aq_av_offset = compute_frame_aq_offset(cpi);

+  }

+}

 static void sum_intra_stats(FRAME_COUNTS *counts, const MODE_INFO *mi) {

   const PREDICTION_MODE y_mode = mi->mode;

   const PREDICTION_MODE uv_mode = mi->uv_mode;

--- a/vp9/encoder/vp9_encoder.c

+++ b/vp9/encoder/vp9_encoder.c

@@ -3137,7 +3137,7 @@

        "%7.2lf %7.2lf %7.2lf %7.2lf %7.2lf"

         "%6d %6d %5d %5d %5d "

         "%10"PRId64" %10.3lf"

-        "%10lf %8u %10"PRId64" %10d %10d %10d %10d\n",

+        "%10lf %8u %10"PRId64" %10d %10d %10d %10d %10d\n",

         cpi->common.current_video_frame,

         cm->width, cm->height,

         cpi->td.rd_counts.m_search_count,

@@ -3171,7 +3171,8 @@

         cpi->tot_recode_hits, recon_err, cpi->rc.kf_boost,

         cpi->twopass.kf_zeromotion_pct,

         cpi->twopass.fr_content_type,

-        cm->lf.filter_level);

+        cm->lf.filter_level,

+        cm->seg.aq_av_offset);

   }

   fclose(f);

--- a/vp9/encoder/vp9_firstpass.c

+++ b/vp9/encoder/vp9_firstpass.c

@@ -2849,6 +2849,7 @@

 void vp9_twopass_postencode_update(VP9_COMP *cpi) {

   TWO_PASS *const twopass = &cpi->twopass;

   RATE_CONTROL *const rc = &cpi->rc;

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

   const int bits_used = rc->base_frame_target;

   // VBR correction is done through rc->vbr_bits_off_target. Based on the

@@ -2886,7 +2887,23 @@

       rc->worst_quality - twopass->active_worst_quality;

     const int minq_adj_limit =

         (cpi->oxcf.rc_mode == VPX_CQ ? MINQ_ADJ_LIMIT_CQ : MINQ_ADJ_LIMIT);

+    int aq_extend_min = 0;

+    int aq_extend_max = 0;

+    // Extend min or Max Q range to account for imbalance from the base

+    // value when using AQ.

+    if (cpi->oxcf.aq_mode != NO_AQ) {

+      if (cm->seg.aq_av_offset < 0) {

+        // The balance of the AQ map tends towarda lowering the average Q.

+        aq_extend_min = 0;

+        aq_extend_max = VPXMIN(maxq_adj_limit, -cm->seg.aq_av_offset);

+      } else {

+        // The balance of the AQ map tends towards raising the average Q.

+        aq_extend_min = VPXMIN(minq_adj_limit, cm->seg.aq_av_offset);

+        aq_extend_max = 0;

+      }

+    }

+

     // Undershoot.

     if (rc->rate_error_estimate > cpi->oxcf.under_shoot_pct) {

       --twopass->extend_maxq;

@@ -2910,8 +2927,10 @@

         --twopass->extend_maxq;

     }

-    twopass->extend_minq = clamp(twopass->extend_minq, 0, minq_adj_limit);

-    twopass->extend_maxq = clamp(twopass->extend_maxq, 0, maxq_adj_limit);

+    twopass->extend_minq =

+        clamp(twopass->extend_minq, aq_extend_min, minq_adj_limit);

+    twopass->extend_maxq =

+        clamp(twopass->extend_maxq, aq_extend_max, maxq_adj_limit);

     // If there is a big and undexpected undershoot then feed the extra

     // bits back in quickly. One situation where this may happen is if a

-- 

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