Rate control fix.

This fix addresses some problems with very complex clips like
handling of flashes on clips like crew (which was made worse
by an earlier patch (derf and std-hd)).

Most clips a small effect but some between 1 & 2%

Derf +0.039, +0.211%
YT +0.042, +0.083%

Change-Id: I65fc7c13afc31482040068544dd65b8808f5cb4a

diff --git a/vp8/encoder/firstpass.c b/vp8/encoder/firstpass.c
index 0d1574c4be3a5ebe5cf5fbfaaf3df0f08d863dec..8c7818c63a3ffc4ad25c5742a1dd8f394e14ab08 100644 (file)
--- a/vp8/encoder/firstpass.c
+++ b/vp8/encoder/firstpass.c
@@ -634,7 +634,14 @@ void vp8_first_pass(VP8_COMP *cpi)
                     xd->pre.u_buffer = lst_yv12->u_buffer + recon_uvoffset;
                     xd->pre.v_buffer = lst_yv12->v_buffer + recon_uvoffset;
 
-                    sr_coded_error += gf_motion_error;
+                    // In accumulating a score for the older reference frame
+                    // take the best of the motion predicted score and
+                    // the intra coded error (just as will be done for)
+                    // accumulation of "coded_error" for the last frame.
+                    if ( gf_motion_error < this_error )
+                        sr_coded_error += gf_motion_error;
+                    else
+                        sr_coded_error += this_error;
                 }
                 else
                     sr_coded_error += motion_error;
@@ -799,12 +806,18 @@ void vp8_first_pass(VP8_COMP *cpi)
     }
 
     // Copy the previous Last Frame back into gf and and arf buffers if
-    // the prediction is good enough.
-    if ((cm->current_video_frame > 0) &&
-        (cpi->twopass.this_frame_stats->pcnt_inter > 0.20))
+    // the prediction is good enough... but also dont allow it to lag too far
+    if ((cpi->twopass.sr_update_lag > 3) ||
+        ((cm->current_video_frame > 0) &&
+         (cpi->twopass.this_frame_stats->pcnt_inter > 0.20) &&
+         ((cpi->twopass.this_frame_stats->intra_error /
+           cpi->twopass.this_frame_stats->coded_error) > 2.0)))
     {
         vp8_yv12_copy_frame_ptr(lst_yv12, gld_yv12);
+        cpi->twopass.sr_update_lag = 1;
     }
+    else
+        cpi->twopass.sr_update_lag ++;
 
     // swap frame pointers so last frame refers to the frame we just compressed
     vp8_swap_yv12_buffer(lst_yv12, new_yv12);
@@ -921,6 +934,11 @@ static double calc_correction_factor( VP8_COMP *cpi,
     correction_factor = correction_factor * sr_correction;
 #endif
 
+    // Clip range
+    correction_factor =
+        (correction_factor < 0.05)
+            ? 0.05 : (correction_factor > 2.0) ? 2.0 : correction_factor;
+
     return correction_factor;
 }
 
@@ -1214,6 +1232,9 @@ void vp8_init_second_pass(VP8_COMP *cpi)
     cpi->twopass.kf_intra_err_min = KF_MB_INTRA_MIN * cpi->common.MBs;
     cpi->twopass.gf_intra_err_min = GF_MB_INTRA_MIN * cpi->common.MBs;
 
+    // This variable monitors how far behind the second ref update is lagging
+    cpi->twopass.sr_update_lag = 1;
+
     // Scan the first pass file and calculate an average Intra / Inter error score ratio for the sequence
     {
         double sum_iiratio = 0.0;
@@ -1277,15 +1298,14 @@ static double get_prediction_decay_rate(VP8_COMP *cpi, FIRSTPASS_STATS *next_fra
             (cpi->common.MBs);
     second_ref_decay = 1.0 - (mb_sr_err_diff / 512.0);
     second_ref_decay = pow( second_ref_decay, 0.5 );
+    if ( second_ref_decay < 0.85 )
+        second_ref_decay = 0.85;
+    else if ( second_ref_decay > 1.0 )
+        second_ref_decay = 1.0;
 
     if ( second_ref_decay < prediction_decay_rate )
         prediction_decay_rate = second_ref_decay;
 
-    if ( prediction_decay_rate < 0.85 )
-        prediction_decay_rate = 0.85;
-    else if ( prediction_decay_rate > 1.0 )
-        prediction_decay_rate = 1.0;
-
     return prediction_decay_rate;
 }
 

diff --git a/vp8/encoder/onyx_int.h b/vp8/encoder/onyx_int.h
index 2644e7ed56d54d08f36fdc4f28c3113d2fbdeefd..b181a609578673839c83fb90263d58c3a9ae71ce 100644 (file)
--- a/vp8/encoder/onyx_int.h
+++ b/vp8/encoder/onyx_int.h
@@ -598,6 +598,8 @@ typedef struct VP8_COMP
         int gf_group_bits;                // Projected Bits available for a group of frames including 1 GF or ARF
         int gf_bits;                     // Bits for the golden frame or ARF - 2 pass only
         int alt_extra_bits;
+
+        int sr_update_lag;
         double est_max_qcorrection_factor;
     } twopass;