Update AUTHORS and CHANGELOG for libaom v3.1.0

It is not necessary to tweak .mailmap to remove duplicates.

BUG=aomedia:3028

Change-Id: I103626bc53a3c3bb99171fd3eed3e39379af7404

AUTHORS

diff --git a/AUTHORS b/AUTHORS
index bb0acb7..d8711a6 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -36,6 +36,7 @@
 Charles 'Buck' Krasic <ckrasic@google.com>
 Cheng Chen <chengchen@google.com>
 Cherma Rajan A <cherma.rajan@ittiam.com>
+Chethan Kumar R E <chethan.kumar@ittiam.com>
 Chi Yo Tsai <chiyotsai@google.com>
 Chm <chm@rock-chips.com>
 Christian Duvivier <cduvivier@google.com>
@@ -166,6 +167,7 @@
 Mirko Bonadei <mbonadei@google.com>
 Monty Montgomery <cmontgomery@mozilla.com>
 Morton Jonuschat <yabawock@gmail.com>
+Mudassir Galagnath <mudassir.galaganath@ittiam.com>
 Mufaddal Chakera <mufaddal.chakera@ittiam.com>
 Nathan E. Egge <negge@mozilla.com>
 Neil Birkbeck <birkbeck@google.com>
@@ -232,6 +234,7 @@
 Tamar Levy <tamar.levy@intel.com>
 Tao Bai <michaelbai@chromium.org>
 Tarek AMARA <amatarek@justin.tv>
+Tarundeep Singh <tarundeep.singh@ittiam.com>
 Tero Rintaluoma <teror@google.com>
 Thijs Vermeir <thijsvermeir@gmail.com>
 Thomas Daede <tdaede@mozilla.com>
@@ -249,6 +252,7 @@
 Victoria Zhislina <niva213@gmail.com>
 Vignesh Venkatasubramanian <vigneshv@google.com>
 Vishesh <vishesh.garg@ittiam.com>
+Vishnu Teja Manyam <vishnu.teja@ittiam.com>
 Vitalii Dziumenko <vdziumenko@luxoft.com>
 Vitalii Dziumenko <vdziumenko@luxoft.corp-partner.google.com>
 Wan-Teh Chang <wtc@google.com>

CHANGELOG

diff --git a/CHANGELOG b/CHANGELOG
index c657503..ebc8e7b 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,42 @@
+2021-04-23 v3.1.0
+  This release adds an "all intra" mode to the encoder, which significantly
+  speeds up the encoding of AVIF still images at speed 6.
+
+  - Upgrading:
+    All intra mode for encoding AVIF still images and AV1 all intra videos:
+    AOM_USAGE_ALL_INTRA (2) can be passed as the 'usage' argument to
+    aom_codec_enc_config_default().
+
+    New encoder control IDs added:
+      - AV1E_SET_ENABLE_DIAGONAL_INTRA: Enable diagonal (D45 to D203) intra
+        prediction modes (0: false, 1: true (default)). Also available as
+        "enable-diagonal-intra" for the aom_codec_set_option() function.
+
+    New aom_tune_metric enum value: AOM_TUNE_BUTTERAUGLI. The new aomenc option
+    --tune=butteraugli was added to optimize the encoder’s perceptual quality by
+    optimizing the Butteraugli metric. Install libjxl (JPEG XL) and then pass
+    -DCONFIG_TUNE_BUTTERAUGLI=1 to the cmake command to enable it.
+
+    Addition of support for libvmaf 2.x.
+
+  - Enhancements:
+    Heap memory consumption for encoding AVIF still images is significantly
+    reduced.
+
+  - Bug fixes:
+    Issue 2950: Conditional expression for rc->this_key_frame_forced is always
+    true in find_next_key_frame()
+
+    Issue 2988: "make install" installs the aom.h header twice
+
+    Issue 2992: Incorrectly printing the temporal_id twice in dump_obu tool
+
+    Issue 2998:
+
+    Issue 2999:
+
+    Issue 3000:
+
 2021-02-24 v3.0.0
   This release includes compression efficiency improvement, speed improvement
   for realtime mode, as well as some new APIs.