diff --git a/modules/audio_processing/BUILD.gn b/modules/audio_processing/BUILD.gn
index 186c43adbe..99314f33d9 100644
--- a/modules/audio_processing/BUILD.gn
+++ b/modules/audio_processing/BUILD.gn
@@ -716,6 +716,7 @@ if (rtc_include_tests) {
         "../../rtc_base:checks",
         "../../rtc_base:protobuf_utils",
         "../../rtc_base:rtc_base_approved",
+        "../../rtc_base:rtc_json",
         "../../rtc_base:rtc_task_queue",
         "../../rtc_base:stringutils",
         "../../system_wrappers",
diff --git a/modules/audio_processing/test/audio_processing_simulator.cc b/modules/audio_processing/test/audio_processing_simulator.cc
index 82bffe427f..28dc7cf5f0 100644
--- a/modules/audio_processing/test/audio_processing_simulator.cc
+++ b/modules/audio_processing/test/audio_processing_simulator.cc
@@ -11,6 +11,7 @@
 #include "modules/audio_processing/test/audio_processing_simulator.h"
 
 #include <algorithm>
+#include <fstream>
 #include <iostream>
 #include <sstream>
 #include <string>
@@ -23,6 +24,7 @@
 #include "modules/audio_processing/include/audio_processing.h"
 #include "modules/audio_processing/test/fake_recording_device.h"
 #include "rtc_base/checks.h"
+#include "rtc_base/json.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/stringutils.h"
 
@@ -30,6 +32,223 @@ namespace webrtc {
 namespace test {
 namespace {
 
+void ReadParam(const Json::Value& root, std::string param_name, bool* param) {
+  RTC_CHECK(param);
+  bool v;
+  if (rtc::GetBoolFromJsonObject(root, param_name, &v)) {
+    *param = v;
+    std::cout << param_name << ":" << (*param ? "true" : "false") << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root, std::string param_name, size_t* param) {
+  RTC_CHECK(param);
+  int v;
+  if (rtc::GetIntFromJsonObject(root, param_name, &v)) {
+    *param = v;
+    std::cout << param_name << ":" << *param << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root, std::string param_name, int* param) {
+  RTC_CHECK(param);
+  int v;
+  if (rtc::GetIntFromJsonObject(root, param_name, &v)) {
+    *param = v;
+    std::cout << param_name << ":" << *param << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root, std::string param_name, float* param) {
+  RTC_CHECK(param);
+  double v;
+  if (rtc::GetDoubleFromJsonObject(root, param_name, &v)) {
+    *param = static_cast<float>(v);
+    std::cout << param_name << ":" << *param << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root,
+               std::string param_name,
+               EchoCanceller3Config::Filter::MainConfiguration* param) {
+  RTC_CHECK(param);
+  Json::Value json_array;
+  if (rtc::GetValueFromJsonObject(root, param_name, &json_array)) {
+    std::vector<double> v;
+    rtc::JsonArrayToDoubleVector(json_array, &v);
+    if (v.size() != 5) {
+      std::cout << "Incorrect array size for " << param_name << std::endl;
+      RTC_CHECK(false);
+    }
+    param->length_blocks = static_cast<size_t>(v[0]);
+    param->leakage_converged = static_cast<float>(v[1]);
+    param->leakage_diverged = static_cast<float>(v[2]);
+    param->error_floor = static_cast<float>(v[3]);
+    param->noise_gate = static_cast<float>(v[4]);
+
+    std::cout << param_name << ":"
+              << "[" << param->length_blocks << "," << param->leakage_converged
+              << "," << param->leakage_diverged << "," << param->error_floor
+              << "," << param->noise_gate << "]" << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root,
+               std::string param_name,
+               EchoCanceller3Config::Filter::ShadowConfiguration* param) {
+  RTC_CHECK(param);
+  Json::Value json_array;
+  if (rtc::GetValueFromJsonObject(root, param_name, &json_array)) {
+    std::vector<double> v;
+    rtc::JsonArrayToDoubleVector(json_array, &v);
+    if (v.size() != 3) {
+      std::cout << "Incorrect array size for " << param_name << std::endl;
+      RTC_CHECK(false);
+    }
+    param->length_blocks = static_cast<size_t>(v[0]);
+    param->rate = static_cast<float>(v[1]);
+    param->noise_gate = static_cast<float>(v[2]);
+    std::cout << param_name << ":"
+              << "[" << param->length_blocks << "," << param->rate << ","
+              << param->noise_gate << "]" << std::endl;
+  }
+}
+
+void ReadParam(const Json::Value& root,
+               std::string param_name,
+               EchoCanceller3Config::GainUpdates::GainChanges* param) {
+  RTC_CHECK(param);
+  Json::Value json_array;
+  if (rtc::GetValueFromJsonObject(root, param_name, &json_array)) {
+    std::vector<double> v;
+    rtc::JsonArrayToDoubleVector(json_array, &v);
+    if (v.size() != 6) {
+      std::cout << "Incorrect array size for " << param_name << std::endl;
+      RTC_CHECK(false);
+    }
+    param->max_inc = static_cast<float>(v[0]);
+    param->max_dec = static_cast<float>(v[1]);
+    param->rate_inc = static_cast<float>(v[2]);
+    param->rate_dec = static_cast<float>(v[3]);
+    param->min_inc = static_cast<float>(v[4]);
+    param->min_dec = static_cast<float>(v[5]);
+
+    std::cout << param_name << ":"
+              << "[" << param->max_inc << "," << param->max_dec << ","
+              << param->rate_inc << "," << param->rate_dec << ","
+              << param->min_inc << "," << param->min_dec << "]" << std::endl;
+  }
+}
+
+EchoCanceller3Config ParseAec3Parameters(const std::string& filename) {
+  EchoCanceller3Config cfg;
+  Json::Value root;
+  std::string s;
+  std::string json_string;
+  std::ifstream f(filename.c_str());
+
+  if (f.fail()) {
+    std::cout << "Failed to open the file " << filename << std::endl;
+    RTC_CHECK(false);
+  }
+
+  while (std::getline(f, s)) {
+    json_string += s;
+  }
+  bool failed = Json::Reader().parse(json_string, root);
+  if (failed) {
+    std::cout << "Incorrect JSON format:" << std::endl;
+    std::cout << json_string << std::endl;
+    RTC_CHECK(false);
+  }
+
+  std::cout << "AEC3 Parameters from JSON input:" << std::endl;
+  Json::Value section;
+  if (rtc::GetValueFromJsonObject(root, "delay", &section)) {
+    ReadParam(section, "default_delay", &cfg.delay.default_delay);
+    ReadParam(section, "down_sampling_factor", &cfg.delay.down_sampling_factor);
+    ReadParam(section, "num_filters", &cfg.delay.num_filters);
+    ReadParam(section, "api_call_jitter_blocks",
+              &cfg.delay.api_call_jitter_blocks);
+    ReadParam(section, "min_echo_path_delay_blocks",
+              &cfg.delay.min_echo_path_delay_blocks);
+    ReadParam(section, "delay_headroom_blocks",
+              &cfg.delay.delay_headroom_blocks);
+    ReadParam(section, "hysteresis_limit_1_blocks",
+              &cfg.delay.hysteresis_limit_1_blocks);
+    ReadParam(section, "hysteresis_limit_2_blocks",
+              &cfg.delay.hysteresis_limit_2_blocks);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "filter", &section)) {
+    ReadParam(section, "main", &cfg.filter.main);
+    ReadParam(section, "shadow", &cfg.filter.shadow);
+    ReadParam(section, "main_initial", &cfg.filter.main_initial);
+    ReadParam(section, "shadow_initial", &cfg.filter.shadow_initial);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "erle", &section)) {
+    ReadParam(section, "min", &cfg.erle.min);
+    ReadParam(section, "max_l", &cfg.erle.max_l);
+    ReadParam(section, "max_h", &cfg.erle.max_h);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "ep_strength", &section)) {
+    ReadParam(section, "lf", &cfg.ep_strength.lf);
+    ReadParam(section, "mf", &cfg.ep_strength.mf);
+    ReadParam(section, "hf", &cfg.ep_strength.hf);
+    ReadParam(section, "default_len", &cfg.ep_strength.default_len);
+    ReadParam(section, "echo_can_saturate", &cfg.ep_strength.echo_can_saturate);
+    ReadParam(section, "bounded_erl", &cfg.ep_strength.bounded_erl);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "gain_mask", &section)) {
+    ReadParam(section, "m1", &cfg.gain_mask.m1);
+    ReadParam(section, "m2", &cfg.gain_mask.m2);
+    ReadParam(section, "m3", &cfg.gain_mask.m3);
+    ReadParam(section, "m4", &cfg.gain_mask.m4);
+    ReadParam(section, "m5", &cfg.gain_mask.m5);
+    ReadParam(section, "m6", &cfg.gain_mask.m6);
+    ReadParam(section, "m7", &cfg.gain_mask.m7);
+    ReadParam(section, "m8", &cfg.gain_mask.m8);
+    ReadParam(section, "m9", &cfg.gain_mask.m9);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "echo_audibility", &section)) {
+    ReadParam(section, "low_render_limit",
+              &cfg.echo_audibility.low_render_limit);
+    ReadParam(section, "normal_render_limit",
+              &cfg.echo_audibility.normal_render_limit);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "gain_updates", &section)) {
+    ReadParam(section, "low_noise", &cfg.gain_updates.low_noise);
+    ReadParam(section, "initial", &cfg.gain_updates.initial);
+    ReadParam(section, "normal", &cfg.gain_updates.normal);
+    ReadParam(section, "saturation", &cfg.gain_updates.saturation);
+    ReadParam(section, "nonlinear", &cfg.gain_updates.nonlinear);
+    ReadParam(section, "floor_first_increase",
+              &cfg.gain_updates.floor_first_increase);
+  }
+
+  if (rtc::GetValueFromJsonObject(root, "echo_removal_control", &section)) {
+    Json::Value subsection;
+    if (rtc::GetValueFromJsonObject(section, "gain_rampup", &subsection)) {
+      ReadParam(section, "first_non_zero_gain",
+                &cfg.echo_removal_control.gain_rampup.first_non_zero_gain);
+      ReadParam(section, "non_zero_gain_blocks",
+                &cfg.echo_removal_control.gain_rampup.non_zero_gain_blocks);
+      ReadParam(section, "full_gain_blocks",
+                &cfg.echo_removal_control.gain_rampup.full_gain_blocks);
+    }
+    ReadParam(section, "has_clock_drift",
+              &cfg.echo_removal_control.has_clock_drift);
+  }
+
+  std::cout << std::endl;
+  return cfg;
+}
+
 void CopyFromAudioFrame(const AudioFrame& src, ChannelBuffer<float>* dest) {
   RTC_CHECK_EQ(src.num_channels_, dest->num_channels());
   RTC_CHECK_EQ(src.samples_per_channel_, dest->num_frames());
@@ -326,7 +545,11 @@ void AudioProcessingSimulator::CreateAudioProcessor() {
     apm_config.gain_controller2.fixed_gain_db = settings_.agc2_fixed_gain_db;
   }
   if (settings_.use_aec3 && *settings_.use_aec3) {
-    echo_control_factory.reset(new EchoCanceller3Factory());
+    EchoCanceller3Config cfg;
+    if (settings_.aec3_settings_filename) {
+      cfg = ParseAec3Parameters(*settings_.aec3_settings_filename);
+    }
+    echo_control_factory.reset(new EchoCanceller3Factory(cfg));
   }
   if (settings_.use_lc) {
     apm_config.level_controller.enabled = *settings_.use_lc;
diff --git a/modules/audio_processing/test/audio_processing_simulator.h b/modules/audio_processing/test/audio_processing_simulator.h
index 41a3f45106..56738d2cbf 100644
--- a/modules/audio_processing/test/audio_processing_simulator.h
+++ b/modules/audio_processing/test/audio_processing_simulator.h
@@ -90,6 +90,7 @@ struct SimulationSettings {
   bool fixed_interface = false;
   bool store_intermediate_output = false;
   rtc::Optional<std::string> custom_call_order_filename;
+  rtc::Optional<std::string> aec3_settings_filename;
 };
 
 // Holds a few statistics about a series of TickIntervals.
diff --git a/modules/audio_processing/test/audioproc_float.cc b/modules/audio_processing/test/audioproc_float.cc
index c5229a4e10..5a3255dcba 100644
--- a/modules/audio_processing/test/audioproc_float.cc
+++ b/modules/audio_processing/test/audioproc_float.cc
@@ -181,6 +181,9 @@ DEFINE_bool(store_intermediate_output,
             false,
             "Creates new output files after each init");
 DEFINE_string(custom_call_order_file, "", "Custom process API call order file");
+DEFINE_string(aec3_settings,
+              "",
+              "File in JSON-format with custom AEC3 settings");
 DEFINE_bool(help, false, "Print this message");
 
 void SetSettingIfSpecified(const std::string& value,
@@ -279,6 +282,7 @@ SimulationSettings CreateSettings() {
                         &settings.stream_drift_samples);
   SetSettingIfSpecified(FLAG_custom_call_order_file,
                         &settings.custom_call_order_filename);
+  SetSettingIfSpecified(FLAG_aec3_settings, &settings.aec3_settings_filename);
   settings.initial_mic_level = FLAG_initial_mic_level;
   settings.simulate_mic_gain = FLAG_simulate_mic_gain;
   SetSettingIfSpecified(FLAG_simulated_mic_kind, &settings.simulated_mic_kind);