Skip the partition search for the frame with no motion

This patch allows the encoder to skip the partition search for the
frame if it is an inter frame and only zero motion vectors have
been detected in the first pass. The partition size is directly
assigned according to the difference variance.

Borg tests show overall little performance changes in term of PSNR
(derf -0.027%, yt 0.152%, hd 0.078%, stdhd 0%). The worst case of
PSNR loss is -0.514% from yt. The best PSNR gain is 4.293% from yt.
The second pass encoding speedup for slideshow clips is 15%-40%.

Change-Id: I881f347d286553ee5594a9ea09ba1a61ac684045

diff --git a/vp9/encoder/vp9_encodeframe.c b/vp9/encoder/vp9_encodeframe.c
index dcd0be686609e51ff0e653229f34af8e04f7238d..e64d402f24961dffedbd9991407b8d3d9788fb73 100644 (file)
--- a/vp9/encoder/vp9_encodeframe.c
+++ b/vp9/encoder/vp9_encodeframe.c
@@ -2309,7 +2309,8 @@ static void encode_rd_sb_row(VP9_COMP *cpi, const TileInfo *const tile,
                                sf->always_this_block_size);
         rd_use_partition(cpi, tile, mi, tp, mi_row, mi_col, BLOCK_64X64,
                          &dummy_rate, &dummy_dist, 1, cpi->pc_root);
-      } else if (sf->partition_search_type == VAR_BASED_FIXED_PARTITION) {
+      } else if (cpi->skippable_frame ||
+                 sf->partition_search_type == VAR_BASED_FIXED_PARTITION) {
         BLOCK_SIZE bsize;
         set_offsets(cpi, tile, mi_row, mi_col, BLOCK_64X64);
         bsize = get_rd_var_based_fixed_partition(cpi, mi_row, mi_col);

diff --git a/vp9/encoder/vp9_encoder.c b/vp9/encoder/vp9_encoder.c
index bc240ff556976cb120eddb86a1f3ec6c5b759504..571ad0c67c3af74df43fee8134dd61affe6463ce 100644 (file)
--- a/vp9/encoder/vp9_encoder.c
+++ b/vp9/encoder/vp9_encoder.c
@@ -743,6 +743,8 @@ VP9_COMP *vp9_create_compressor(VP9EncoderConfig *oxcf) {
   cpi->alt_is_last = 0;
   cpi->gold_is_alt = 0;
 
+  cpi->skippable_frame = 0;
+
   // Create the encoder segmentation map and set all entries to 0
   CHECK_MEM_ERROR(cm, cpi->segmentation_map,
                   vpx_calloc(cm->mi_rows * cm->mi_cols, 1));
@@ -1972,6 +1974,29 @@ YV12_BUFFER_CONFIG *vp9_scale_if_required(VP9_COMMON *cm,
   }
 }
 
+static void configure_skippable_frame(VP9_COMP *cpi) {
+  // If the current frame does not have non-zero motion vector detected in the
+  // first  pass, and so do its previous and forward frames, then this frame
+  // can be skipped for partition check, and the partition size is assigned
+  // according to the variance
+
+  SVC *const svc = &cpi->svc;
+  const int is_spatial_svc = (svc->number_spatial_layers > 1) &&
+                             (svc->number_temporal_layers == 1);
+  TWO_PASS *const twopass = is_spatial_svc ?
+                            &svc->layer_context[svc->spatial_layer_id].twopass
+                            : &cpi->twopass;
+
+  cpi->skippable_frame = (!frame_is_intra_only(&cpi->common) &&
+    twopass->stats_in - 2 > twopass->stats_in_start &&
+    twopass->stats_in < twopass->stats_in_end &&
+    (twopass->stats_in - 1)->pcnt_inter - (twopass->stats_in - 1)->pcnt_motion
+    == 1 &&
+    (twopass->stats_in - 2)->pcnt_inter - (twopass->stats_in - 2)->pcnt_motion
+    == 1 &&
+    twopass->stats_in->pcnt_inter - twopass->stats_in->pcnt_motion == 1);
+}
+
 static void encode_frame_to_data_rate(VP9_COMP *cpi,
                                       size_t *size,
                                       uint8_t *dest,
@@ -2067,6 +2092,13 @@ static void encode_frame_to_data_rate(VP9_COMP *cpi,
   if (cpi->pass == 2 && cpi->sf.static_segmentation)
     configure_static_seg_features(cpi);
 
+  // Check if the current frame is skippable for the partition search in the
+  // second pass according to the first pass stats
+  if (cpi->pass == 2 &&
+      (!cpi->use_svc || cpi->svc.number_temporal_layers == 1)) {
+    configure_skippable_frame(cpi);
+  }
+
   // For 1 pass CBR, check if we are dropping this frame.
   // Never drop on key frame.
   if (cpi->pass == 0 &&

diff --git a/vp9/encoder/vp9_encoder.h b/vp9/encoder/vp9_encoder.h
index a80ab1bd6204628adf05b0b6fa876e381ce7a95e..a5b465a63c544c26dc4d78b1a7ecf9417c6d1939 100644 (file)
--- a/vp9/encoder/vp9_encoder.h
+++ b/vp9/encoder/vp9_encoder.h
@@ -266,6 +266,8 @@ typedef struct VP9_COMP {
   int alt_is_last;  // Alt same as last ( short circuit altref search)
   int gold_is_alt;  // don't do both alt and gold search ( just do gold).
 
+  int skippable_frame;
+
   int scaled_ref_idx[3];
   int lst_fb_idx;
   int gld_fb_idx;