shithub: libvpx

Download patch

ref: c8338ebf7acba1f0a2d0d182b643c5c14417e33a
parent: b082790c7d1e16dde329f1baea153c0fe86112d5
author: Paul Wilkins <paulwilkins@google.com>
date: Fri Jan 14 06:34:53 EST 2011 

KF/GF Pulsing

This change is designed to try and reduce pulsing effects when moving
with a complex transition like a fade, into an easy or static section in
an otherwise difficult clip in CQ mode.

The active CQ level is relaxed down to the user entered level for frames that
are generating less than the passed in minimum bandwidth.

Change-Id: Id6d8b551daad4f489c087bd742bc95418a95f3f0


--- a/vp8/encoder/onyx_if.c
+++ b/vp8/encoder/onyx_if.c
@@ -2029,7 +2029,7 @@
     cpi->buffered_mode = (cpi->oxcf.optimal_buffer_level > 0) ? TRUE : FALSE;
 
     // Experimental cq target value
-    cpi->cq_target_quality = oxcf->cq_level;
+    cpi->cq_target_quality = cpi->oxcf.cq_level;
 
     cpi->rolling_target_bits          = cpi->av_per_frame_bandwidth;
     cpi->rolling_actual_bits          = cpi->av_per_frame_bandwidth;
@@ -3519,14 +3519,29 @@
     {
         // General over and under shoot tests
         if ( ((cpi->projected_frame_size > high_limit) && (q < maxq)) ||
-             ((cpi->projected_frame_size < low_limit) && (q > minq)) ||
-             ((cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) &&
-              (q > cpi->cq_target_quality) &&
-              (cpi->projected_frame_size <
-                  ((cpi->this_frame_target * 7) >> 3))) )
+             ((cpi->projected_frame_size < low_limit) && (q > minq)) )
         {
             force_recode = TRUE;
         }
+        // Special Constrained quality tests
+        else if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY)
+        {
+            // Undershoot and below auto cq level
+            if ( (q > cpi->cq_target_quality) &&
+                 (cpi->projected_frame_size <
+                     ((cpi->this_frame_target * 7) >> 3)))
+            {
+                force_recode = TRUE;
+            }
+            // Severe undershoot and between auto and user cq level
+            else if ( (q > cpi->oxcf.cq_level) &&
+                      (cpi->projected_frame_size < cpi->min_frame_bandwidth) &&
+                      (cpi->active_best_quality > cpi->oxcf.cq_level))
+            {
+                force_recode = TRUE;
+                cpi->active_best_quality = cpi->oxcf.cq_level;
+            }
+        }
     }
 
     return force_recode;
@@ -3853,7 +3868,13 @@
             if ((cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) &&
                 (cpi->active_best_quality < cpi->cq_target_quality) )
             {
-                cpi->active_best_quality = cpi->cq_target_quality;
+                // If we are strongly undershooting the target rate in the last
+                // frames then use the user passed in cq value not the auto
+                // cq value.
+                if ( cpi->rolling_actual_bits < cpi->min_frame_bandwidth )
+                    cpi->active_best_quality = cpi->oxcf.cq_level;
+                else
+                    cpi->active_best_quality = cpi->cq_target_quality;
             }
         }
 
@@ -4218,6 +4239,16 @@
                         vp8_update_rate_correction_factors(cpi, 0);
 
                     Q = vp8_regulate_q(cpi, cpi->this_frame_target);
+
+                    // Special case reset for qlow for constrained quality.
+                    // This should only trigger where there is very substantial
+                    // undershoot on a frame and the auto cq level is above
+                    // the user passsed in value.
+                    if ( (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) &&
+                         (Q < q_low) )
+                    {
+                        q_low = Q;
+                    }
 
                     while (((Q > q_high) || (cpi->zbin_over_quant > zbin_oq_high)) && (Retries < 10))
                     {