shithub: libvpx

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ref: 78df71221656b0a0d37bff6c16efd743347fa30d
parent: 6eaca27df21d2bd8da1c063c484b5f5c28621d3a
author: Adrian Grange <agrange@google.com>
date: Tue Mar 10 05:14:54 EDT 2015

Fix vp9_compute_qdelta_by_rate loop behavior

The return value from vp9_compute_qdelta_by_rate, which is
a delta value for the quantizer, could never be 0 if
(qindex == rc->worst_quality).

This occurs because target_index was setup unconditionally
in the loop and yet the loop counter stopped at
(rc->worst_quality - 1).

Change-Id: I6b59cd9b5811ff33357e71cd7d814c5e53d291f2

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

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

@@ -1595,11 +1595,12 @@

   // Convert the q target to an index

   for (i = rc->best_quality; i < rc->worst_quality; ++i) {

-    target_index = i;

-    if (vp9_rc_bits_per_mb(frame_type, i, 1.0, bit_depth) <= target_bits_per_mb)

+    if (vp9_rc_bits_per_mb(frame_type, i, 1.0, bit_depth) <=

+        target_bits_per_mb) {

+      target_index = i;

       break;

+    }

   }

-

   return target_index - qindex;

 }