Update CHANGELOG for libaom 3.8.0

Bug: aomedia:3515
Change-Id: I4229073c25879d9f562ae7f2acbb316f9791bb3d

CHANGELOG

diff --git a/CHANGELOG b/CHANGELOG
index 5cd6634..9f0cabb 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,4 +1,4 @@
-2023-11-23 v3.8.0
+2023-11-30 v3.8.0
   This release includes new codec interfaces, compression efficiency and
   perceptual improvements, speedup and memory optimizations and many bug
   fixes. This release is ABI compatible with the last release.
@@ -12,13 +12,45 @@
       CRC, DotProd, I8MM and SVE CPU feature presence is detected at run
       time and code paths making use of these features are selected
       dynamically. These code paths provide meaningful performance gains
-      for standard bitdepth live-stream and VoD encoding: up to 10% and
-      20% respectively, over the Armv8.0-A baseline build.
+      for standard bitdepth RTC and VoD encoding: up to 10% and 20%
+      respectively, over the Armv8.0-A baseline build.
+    * RTC: Frame-dropper support added to the rate control library.
+    * RTC Rate control improvements for low bitrate and for SVC.
+
+  - Compression Efficiency Improvements
+    * Improved accuracy of cost estimation for loop restoration and
+      global motion.
+    * Improved selection of loop restoration unit size - full search up
+      to (non-realtime) speed 2, retuned static selection at higher
+      speeds.
+    * RTC Screen content mode: 3-5% bdrate gains across speeds 7 - 10.
+    * Good-quality mode: 0.2 - 0.5% bdrate gains across speeds 1 - 4.
+
+  - Perceptual Quality Improvements
+    * RTC Screen: Improved visual quality for scrolling.
+    * RTC: Improved color quality for both screen and video mode.
 
   - Speedup and Memory Optimizations
     * Good-quality, single-thread encoder speedups:
-      o 15% improvement for speed 5
-      o 12% improvement for speed 6
+      o 15% improvement for speed 5.
+      o 12% improvement for speed 6.
+    * Arm standard bitdepth VoD (--good):
+      o 8% speedup for speeds 0 and 1.
+      o 20% speedup for speed 2.
+      o 27% speedup for speed 3.
+      o 30% speedup for speed 4.
+      o 38% speedup for speeds 5 and 6.
+    * Arm high bitdepth VoD (--good):
+      o 206% speedup for speeds 0 and 1.
+      o 180% speedup for speed 2.
+      o 51% speedup for speeds 3 and 4.
+      o 68% speedup for speed 5.
+      o 72% speedup for speed 6.
+    * RTC Screen content: 2-6% speedup across speeds 7-10.
+    * RTC: 2-3% speedup for temporal layers.
+    * RTC: Speedups to reference scaling in nonrd pickmode.
+    * Good-quality mode: Simplified global motion estimation, saving
+      ~1200 lines of code and 1KB of tables while improving quality.
 
   - Bug Fixes
     * Fixes to improve libaom stability in case of memory allocation