Commit c3315eeb3e for aom

commit c3315eeb3e5e1ef4c6b932e8b1b2d4ce22421738
Author: Yunqing Wang <yunqingwang@google.com>
Date:   Thu Feb 5 14:24:48 2026 -0800

    Add low-complexity decode mode test

    This is to monitor the decoder speed change for each submitted
    patch.

    Change-Id: I4618ef8672c7bb0aa89ffb67860bd6669fd0f824

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5a6551ec3a..d9973c47c0 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -801,6 +801,15 @@ if(ENABLE_EXAMPLES AND CONFIG_AV1_ENCODER AND CONFIG_AV1_DECODER)
   list(APPEND AOM_APP_TARGETS lightfield_bitstream_parsing)
 endif()

+if(ENABLE_EXAMPLES AND CONFIG_AV1_ENCODER)
+  add_executable(low_complexity_mode_encoder
+                 "${AOM_ROOT}/examples/low_complexity_mode_encoder.c"
+                 $<TARGET_OBJECTS:aom_common_app_util>
+                 $<TARGET_OBJECTS:aom_encoder_app_util>)
+  list(APPEND AOM_EXAMPLE_TARGETS low_complexity_mode_encoder)
+  list(APPEND AOM_APP_TARGETS low_complexity_mode_encoder)
+endif()
+
 foreach(aom_app ${AOM_APP_TARGETS})
   target_link_libraries(${aom_app} ${AOM_LIB_LINK_TYPE} aom)
 endforeach()
diff --git a/docs.cmake b/docs.cmake
index 154cb0d722..1b76161ca2 100644
--- a/docs.cmake
+++ b/docs.cmake
@@ -199,6 +199,16 @@ if(CONFIG_AV1_DECODER AND CONFIG_AV1_ENCODER)
                                        "Lightfield bitstream parsing example.")
 endif()

+if(CONFIG_AV1_DECODER AND CONFIG_AV1_ENCODER)
+  set(AOM_DOXYGEN_EXAMPLE_SOURCES
+      ${AOM_DOXYGEN_EXAMPLE_SOURCES}
+      "${AOM_ROOT}/examples/low_complexity_mode_encoder.c")
+
+  set(AOM_DOXYGEN_EXAMPLE_DESCRIPTIONS
+      ${AOM_DOXYGEN_EXAMPLE_DESCRIPTIONS}
+      "Low complexity decode mode encoder example.")
+endif()
+
 # Iterates over list named by $list_name and appends each item to $AOM_DOXYFILE
 # as values assigned to $var_name with no line breaks between list items.
 # Appends a new line after the entire config variable is expanded.
diff --git a/examples/low_complexity_mode_encoder.c b/examples/low_complexity_mode_encoder.c
new file mode 100644
index 0000000000..c80326f2bf
--- /dev/null
+++ b/examples/low_complexity_mode_encoder.c
@@ -0,0 +1,175 @@
+/*
+ * Copyright (c) 2026, Alliance for Open Media. All rights reserved.
+ *
+ * This source code is subject to the terms of the BSD 2 Clause License and
+ * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+ * was not distributed with this source code in the LICENSE file, you can
+ * obtain it at www.aomedia.org/license/software. If the Alliance for Open
+ * Media Patent License 1.0 was not distributed with this source code in the
+ * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+ */
+
+// Low Complexity (LC) Mode Encoder
+// ================================
+//
+// This is an example of a low complexity mode encoder. It takes an input
+// file in Y4M format, passes it through the encoder with LC mode on, and
+// writes the compressed frames to disk in IVF format.
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "aom/aom_encoder.h"
+#include "aom/aomcx.h"
+#include "common/tools_common.h"
+#include "common/video_writer.h"
+
+static const char *exec_name;
+
+void usage_exit(void) {
+  fprintf(stderr,
+          "Usage: %s <width> <height> <infile> <outfile> "
+          "<keyframe-interval> <frames to encode>\n",
+          exec_name);
+  exit(EXIT_FAILURE);
+}
+
+static int encode_frame(aom_codec_ctx_t *codec, aom_image_t *img,
+                        int frame_index, int flags, AvxVideoWriter *writer) {
+  int got_pkts = 0;
+  aom_codec_iter_t iter = NULL;
+  const aom_codec_cx_pkt_t *pkt = NULL;
+  const aom_codec_err_t res =
+      aom_codec_encode(codec, img, frame_index, 1, flags);
+  if (res != AOM_CODEC_OK) die_codec(codec, "Failed to encode frame");
+
+  while ((pkt = aom_codec_get_cx_data(codec, &iter)) != NULL) {
+    got_pkts = 1;
+
+    if (pkt->kind == AOM_CODEC_CX_FRAME_PKT) {
+      const int keyframe = (pkt->data.frame.flags & AOM_FRAME_IS_KEY) != 0;
+      if (!aom_video_writer_write_frame(writer, pkt->data.frame.buf,
+                                        pkt->data.frame.sz,
+                                        pkt->data.frame.pts)) {
+        die_codec(codec, "Failed to write compressed frame");
+      }
+      printf(keyframe ? "K" : ".");
+      fflush(stdout);
+    }
+  }
+
+  return got_pkts;
+}
+
+int main(int argc, char **argv) {
+  FILE *infile = NULL;
+  aom_codec_ctx_t codec;
+  aom_codec_enc_cfg_t cfg;
+  int frame_count = 0;
+  aom_image_t raw;
+  aom_codec_err_t res;
+  AvxVideoInfo info;
+  AvxVideoWriter *writer = NULL;
+  const int fps = 30;
+  const int bitrate = 400;
+  int keyframe_interval = 0;
+  int max_frames = 0;
+  int frames_encoded = 0;
+  const char *codec_arg = NULL;
+  const char *width_arg = NULL;
+  const char *height_arg = NULL;
+  const char *infile_arg = NULL;
+  const char *outfile_arg = NULL;
+  const char *keyframe_interval_arg = NULL;
+  const int usage = 0;  // AOM_USAGE_GOOD_QUALITY
+  const int speed = 2;
+
+  exec_name = argv[0];
+
+  // Clear explicitly, as simply assigning "{ 0 }" generates
+  // "missing-field-initializers" warning in some compilers.
+  memset(&info, 0, sizeof(info));
+
+  if (argc != 9) die("Invalid number of arguments");
+
+  codec_arg = argv[1];
+  width_arg = argv[2];
+  height_arg = argv[3];
+  infile_arg = argv[4];
+  outfile_arg = argv[5];
+  keyframe_interval_arg = argv[6];
+  max_frames = (int)strtol(argv[7], NULL, 0);
+
+  aom_codec_iface_t *encoder = get_aom_encoder_by_short_name(codec_arg);
+  if (!encoder) die("Unsupported codec.");
+
+  info.codec_fourcc = get_fourcc_by_aom_encoder(encoder);
+  info.frame_width = (int)strtol(width_arg, NULL, 0);
+  info.frame_height = (int)strtol(height_arg, NULL, 0);
+  info.time_base.numerator = 1;
+  info.time_base.denominator = fps;
+
+  if (info.frame_width <= 0 || info.frame_height <= 0 ||
+      (info.frame_width % 2) != 0 || (info.frame_height % 2) != 0) {
+    die("Invalid frame size: %dx%d", info.frame_width, info.frame_height);
+  }
+
+  if (!aom_img_alloc(&raw, AOM_IMG_FMT_I420, info.frame_width,
+                     info.frame_height, 1)) {
+    die("Failed to allocate image.");
+  }
+
+  keyframe_interval = (int)strtol(keyframe_interval_arg, NULL, 0);
+  if (keyframe_interval < 0) die("Invalid keyframe interval value.");
+
+  printf("Using %s\n", aom_codec_iface_name(encoder));
+
+  res = aom_codec_enc_config_default(encoder, &cfg, usage);
+  if (res) die_codec(&codec, "Failed to get default codec config.");
+
+  cfg.g_w = info.frame_width;
+  cfg.g_h = info.frame_height;
+  cfg.g_timebase.num = info.time_base.numerator;
+  cfg.g_timebase.den = info.time_base.denominator;
+  cfg.rc_target_bitrate = bitrate;
+
+  writer = aom_video_writer_open(outfile_arg, kContainerIVF, &info);
+  if (!writer) die("Failed to open %s for writing.", outfile_arg);
+
+  if (!(infile = fopen(infile_arg, "rb")))
+    die("Failed to open %s for reading.", infile_arg);
+
+  if (aom_codec_enc_init(&codec, encoder, &cfg, 0))
+    die("Failed to initialize encoder");
+
+  if (aom_codec_control(&codec, AOME_SET_CPUUSED, speed))
+    die_codec(&codec, "Failed to set cpu-used");
+
+  if (aom_codec_control(&codec, AV1E_SET_ENABLE_LOW_COMPLEXITY_DECODE, 1))
+    die_codec(&codec, "Failed to set low-complexity mode");
+
+  // Encode frames.
+  while (aom_img_read(&raw, infile)) {
+    int flags = 0;
+    if (keyframe_interval > 0 && frame_count % keyframe_interval == 0)
+      flags |= AOM_EFLAG_FORCE_KF;
+    encode_frame(&codec, &raw, frame_count++, flags, writer);
+    frames_encoded++;
+    if (max_frames > 0 && frames_encoded >= max_frames) break;
+  }
+
+  // Flush encoder.
+  while (encode_frame(&codec, NULL, -1, 0, writer)) continue;
+
+  printf("\n");
+  fclose(infile);
+  printf("Processed %d frames.\n", frame_count);
+
+  aom_img_free(&raw);
+  if (aom_codec_destroy(&codec)) die_codec(&codec, "Failed to destroy codec.");
+
+  aom_video_writer_close(writer);
+
+  return EXIT_SUCCESS;
+}
diff --git a/test/examples.sh b/test/examples.sh
index 6869d025ca..7eb4464d21 100755
--- a/test/examples.sh
+++ b/test/examples.sh
@@ -19,7 +19,7 @@ example_tests=$(ls -r $(dirname $0)/*.sh)
 exclude_list="best_encode examples run_encodes tools_common"

 if [ "$(realtime_only_build)" = "yes" ]; then
-  exclude_list="${exclude_list} twopass_encoder simple_decoder lightfield_test"
+  exclude_list="${exclude_list} twopass_encoder simple_decoder lightfield_test low_complexity_decode_mode_test"
 fi

 # Filter out the scripts in $exclude_list.
diff --git a/test/low_complexity_test.sh b/test/low_complexity_test.sh
new file mode 100755
index 0000000000..fd494db577
--- /dev/null
+++ b/test/low_complexity_test.sh
@@ -0,0 +1,88 @@
+#!/bin/sh
+## Copyright (c) 2026, Alliance for Open Media. All rights reserved.
+##
+## This source code is subject to the terms of the BSD 2 Clause License and
+## the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
+## was not distributed with this source code in the LICENSE file, you can
+## obtain it at www.aomedia.org/license/software. If the Alliance for Open
+## Media Patent License 1.0 was not distributed with this source code in the
+## PATENTS file, you can obtain it at www.aomedia.org/license/patent.
+##
+## This file tests the libaom low-complexity decode mode using simple_encoder
+## and simple_decoder example. The decoder outputs the instruction counts that
+## can be used for decoder speed monitoring.
+##
+. $(dirname $0)/tools_common.sh
+
+# Environment check: $infile is required.
+low_complexity_test_verify_environment() {
+  if [ ! "$(av1_encode_available)" = "yes" ] || \
+    [ ! "$(av1_decode_available)" = "yes" ]; then
+    echo "Encoder and decoder needs to be available."
+    return 1
+  fi
+
+  local infile="${LIBAOM_TEST_DATA_PATH}/SDR_Sports_6mug_608p_30fps_90f.yuv"
+  if [ ! -e "${infile}" ]; then
+    echo "Libaom test data must exist in LIBAOM_TEST_DATA_PATH."
+    return 1
+  fi
+
+  command -v perf >/dev/null 2>&1
+  if [ $? -ne 0 ]; then
+    echo "Perf does not exist. Please install it."
+    return 1
+  fi
+}
+
+# Runs libaom low-complexity decode mode test
+low_complexity_mode_test() {
+  local img_width=608
+  local img_height=1080
+
+  # Encode in low-complexity decode mode
+  local encoder="${LIBAOM_BIN_PATH}/low_complexity_mode_encoder${AOM_TEST_EXE_SUFFIX}"
+  local input_file="${LIBAOM_TEST_DATA_PATH}/SDR_Sports_6mug_608p_30fps_90f.yuv"
+  local ivf_file="${AOM_TEST_OUTPUT_DIR}/low_complexity_mode_encoder.bin"
+
+  if [ ! -x "${encoder}" ]; then
+    elog "${encoder} does not exist or is not executable."
+    return 1
+  fi
+
+  echo "The LC mode encoder is started."
+  eval "${AOM_TEST_PREFIX}" "${encoder}" av1 "${img_width}" \
+      "${img_height}" "${input_file}" "${ivf_file}" 9999 0 90 \
+      ${devnull} || return 1
+
+  [ -e "${ivf_file}" ] || return 1
+  echo "The LC mode encoder is completed."
+
+  # Use simple_decoder to decode the generated bitstream and collect the
+  # instruction counts.
+  local decoder="${LIBAOM_BIN_PATH}/simple_decoder${AOM_TEST_EXE_SUFFIX}"
+  local perfstat_file="${AOM_TEST_OUTPUT_DIR}/perfstat.txt"
+  local perf_prefix="perf stat --no-big-num -e instructions:u -o ${perfstat_file}"
+  local output_file="${AOM_TEST_OUTPUT_DIR}/low_complexity_mode_encoder.out"
+
+  if [ ! -x "${decoder}" ]; then
+    elog "${decoder} does not exist or is not executable."
+    return 1
+  fi
+
+  local dec_cmd="$(echo "${perf_prefix}" "${AOM_TEST_PREFIX}" "${decoder}" \
+                 "${ivf_file}" "${output_file}" ${devnull})"
+  echo "$dec_cmd"
+  eval "$dec_cmd" || return 1
+
+  # Get perf user instruction count in thousands from perf output
+  local instruction_count="0"
+  local line=$( cat ${perfstat_file} | grep "instructions:u" )
+  instruction_count=${line%instructions:u*}
+  echo ${instruction_count}
+}
+
+low_complexity_decode_mode_test="low_complexity_mode_test"
+
+run_tests low_complexity_test_verify_environment \
+  "${low_complexity_decode_mode_test}"