shithub: libvpx

Download patch

ref: db5f2cb57b39545d01e623e04450ba21ae1371aa
parent: 117514b30feabd02fa3db49e502fe4de3beff5ae
author: John Koleszar <jkoleszar@google.com>
date: Fri Mar 15 13:26:24 EDT 2013 

Fix use of NaN in firstpass

If the second reference is better than the first in the long term,
it was possible to try to take the fractional exponent of a
negative number, giving an undefined result.

Change-Id: I1dd08286747ceae960eb03bb5d98a383cc9d253b


--- a/vp9/encoder/vp9_firstpass.c
+++ b/vp9/encoder/vp9_firstpass.c
@@ -859,6 +859,8 @@
   power_term = (power_term > pt_high) ? pt_high : power_term;
 
   // Calculate correction factor
+  if (power_term < 1.0)
+    assert(error_term >= 0.0);
   correction_factor = pow(error_term, power_term);
 
   // Clip range
@@ -920,15 +922,19 @@
 
   // Look at the drop in prediction quality between the last frame
   // and the GF buffer (which contained an older frame).
-  sr_err_diff =
-    (fpstats->sr_coded_error - fpstats->coded_error) /
-    (fpstats->count * cpi->common.MBs);
-  sr_correction = (sr_err_diff / 32.0);
-  sr_correction = pow(sr_correction, 0.25);
-  if (sr_correction < 0.75)
+  if (fpstats->sr_coded_error > fpstats->coded_error) {
+    sr_err_diff =
+      (fpstats->sr_coded_error - fpstats->coded_error) /
+      (fpstats->count * cpi->common.MBs);
+    sr_correction = (sr_err_diff / 32.0);
+    sr_correction = pow(sr_correction, 0.25);
+    if (sr_correction < 0.75)
+      sr_correction = 0.75;
+    else if (sr_correction > 1.25)
+      sr_correction = 1.25;
+  } else {
     sr_correction = 0.75;
-  else if (sr_correction > 1.25)
-    sr_correction = 1.25;
+  }
 
   // Calculate a corrective factor based on a rolling ratio of bits spent
   // vs target bits
@@ -1031,15 +1037,19 @@
 
   // Look at the drop in prediction quality between the last frame
   // and the GF buffer (which contained an older frame).
-  sr_err_diff =
-    (fpstats->sr_coded_error - fpstats->coded_error) /
-    (fpstats->count * cpi->common.MBs);
-  sr_correction = (sr_err_diff / 32.0);
-  sr_correction = pow(sr_correction, 0.25);
-  if (sr_correction < 0.75)
+  if (fpstats->sr_coded_error > fpstats->coded_error) {
+    sr_err_diff =
+      (fpstats->sr_coded_error - fpstats->coded_error) /
+      (fpstats->count * cpi->common.MBs);
+    sr_correction = (sr_err_diff / 32.0);
+    sr_correction = pow(sr_correction, 0.25);
+    if (sr_correction < 0.75)
+      sr_correction = 0.75;
+    else if (sr_correction > 1.25)
+      sr_correction = 1.25;
+  } else {
     sr_correction = 0.75;
-  else if (sr_correction > 1.25)
-    sr_correction = 1.25;
+  }
 
   // II ratio correction factor for clip as a whole
   clip_iiratio = cpi->twopass.total_stats->intra_error /
@@ -1178,12 +1188,16 @@
   mb_sr_err_diff =
     (next_frame->sr_coded_error - next_frame->coded_error) /
     (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)
+  if (mb_sr_err_diff <= 512.0) {
+    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;
+  } else {
     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;