shithub: libvpx

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Apply finer quantizer to partition search frames in non-RD flow

This commit optimizes the bit allocation for the non-RD coding flow.
It applies slightly better quantizer to the frames, where all blocks
run a non-RD partition search. Such frames typically have better
rate-distortion trade off, thus improving the reconstruction quality
for next few frames reference at reasonably low increment in rate
cost.

The coding performance for rtc set at speed -5 with error-resilient
tuned on and rate control set as cbr is improved by 19.58%. It improved
the coding speed by about 10% for a portion of local test clips.

Change-Id: I9d56696cd4359dc8136ca10aff10fff05aaa2686

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

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

@@ -1377,6 +1377,7 @@

     for (block_col = 0; block_col < 8; ++block_col) {

       MODE_INFO *const prev_mi = prev_mi_8x8[block_row * mis + block_col];

       const BLOCK_SIZE sb_type = prev_mi ? prev_mi->mbmi.sb_type : 0;

+

       if (prev_mi) {

         const ptrdiff_t offset = prev_mi - cm->prev_mi;

         mi_8x8[block_row * mis + block_col] = cm->mi + offset;

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

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

@@ -2673,6 +2673,8 @@

   vp9_write_yuv_frame(cpi->Source);

 #endif

+  set_speed_features(cpi);

+

   // Decide q and q bounds.

   q = vp9_rc_pick_q_and_bounds(cpi, &bottom_index, &top_index);

@@ -2681,8 +2683,6 @@

     /* TODO: Decide this more intelligently */

     set_high_precision_mv(cpi, q < HIGH_PRECISION_MV_QTHRESH);

   }

-

-  set_speed_features(cpi);

   if (cpi->sf.recode_loop == DISALLOW_RECODE) {

     encode_without_recode_loop(cpi, size, dest, q);

--- a/vp9/encoder/vp9_ratectrl.c

+++ b/vp9/encoder/vp9_ratectrl.c

@@ -985,6 +985,9 @@

       q /= 3;

     if (q == 0)

       q++;

+    if (cpi->sf.partition_check == 1)

+      q -= 10;

+

     if (q < *bottom_index)

       *bottom_index = q;

     else if (q > *top_index)

-- 

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