diff --git a/modules/audio_coding/acm2/audio_coding_module.cc b/modules/audio_coding/acm2/audio_coding_module.cc
index b68579b..ee31900 100644
--- a/modules/audio_coding/acm2/audio_coding_module.cc
+++ b/modules/audio_coding/acm2/audio_coding_module.cc
@@ -38,6 +38,8 @@
 // 48 kHz data.
 constexpr size_t kInitialInputDataBufferSize = 6 * 480;
 
+constexpr int32_t kMaxInputSampleRateHz = 192000;
+
 class AudioCodingModuleImpl final : public AudioCodingModule {
  public:
   explicit AudioCodingModuleImpl(const AudioCodingModule::Config& config);
@@ -348,7 +350,7 @@
     return -1;
   }
 
-  if (audio_frame.sample_rate_hz_ > 192000) {
+  if (audio_frame.sample_rate_hz_ > kMaxInputSampleRateHz) {
     assert(false);
     RTC_LOG(LS_ERROR) << "Cannot Add 10 ms audio, input frequency not valid";
     return -1;
@@ -465,20 +467,25 @@
   *ptr_out = &preprocess_frame_;
   preprocess_frame_.num_channels_ = in_frame.num_channels_;
   preprocess_frame_.samples_per_channel_ = in_frame.samples_per_channel_;
-  std::array<int16_t, WEBRTC_10MS_PCM_AUDIO> audio;
-  const int16_t* src_ptr_audio = in_frame.data();
+  std::array<int16_t, AudioFrame::kMaxDataSizeSamples> audio;
+  const int16_t* src_ptr_audio;
   if (down_mix) {
-    // If a resampling is required the output of a down-mix is written into a
+    // If a resampling is required, the output of a down-mix is written into a
     // local buffer, otherwise, it will be written to the output frame.
     int16_t* dest_ptr_audio =
         resample ? audio.data() : preprocess_frame_.mutable_data();
+    RTC_DCHECK_GE(audio.size(), preprocess_frame_.samples_per_channel_);
     RTC_DCHECK_GE(audio.size(), in_frame.samples_per_channel_);
     DownMixFrame(in_frame,
                  rtc::ArrayView<int16_t>(
                      dest_ptr_audio, preprocess_frame_.samples_per_channel_));
     preprocess_frame_.num_channels_ = 1;
-    // Set the input of the resampler is the down-mixed signal.
+
+    // Set the input of the resampler to the down-mixed signal.
     src_ptr_audio = audio.data();
+  } else {
+    // Set the input of the resampler to the original data.
+    src_ptr_audio = in_frame.data();
   }
 
   preprocess_frame_.timestamp_ = expected_codec_ts_;
diff --git a/modules/audio_coding/include/audio_coding_module.h b/modules/audio_coding/include/audio_coding_module.h
index d8c9260..4d75172 100644
--- a/modules/audio_coding/include/audio_coding_module.h
+++ b/modules/audio_coding/include/audio_coding_module.h
@@ -33,8 +33,6 @@
 class AudioFrame;
 struct RTPHeader;
 
-#define WEBRTC_10MS_PCM_AUDIO 960  // 16 bits super wideband 48 kHz
-
 // Callback class used for sending data ready to be packetized
 class AudioPacketizationCallback {
  public:
diff --git a/modules/audio_coding/test/EncodeDecodeTest.cc b/modules/audio_coding/test/EncodeDecodeTest.cc
index 20e415d..7633dc2 100644
--- a/modules/audio_coding/test/EncodeDecodeTest.cc
+++ b/modules/audio_coding/test/EncodeDecodeTest.cc
@@ -24,6 +24,12 @@
 
 namespace webrtc {
 
+namespace {
+// Buffer size for stereo 48 kHz audio.
+constexpr size_t kWebRtc10MsPcmAudio = 960;
+
+}  // namespace
+
 TestPacketization::TestPacketization(RTPStream* rtpStream, uint16_t frequency)
     : _rtpStream(rtpStream), _frequency(frequency), _seqNo(0) {}
 
@@ -91,7 +97,7 @@
 }
 
 Receiver::Receiver()
-    : _playoutLengthSmpls(WEBRTC_10MS_PCM_AUDIO),
+    : _playoutLengthSmpls(kWebRtc10MsPcmAudio),
       _payloadSizeBytes(MAX_INCOMING_PAYLOAD) {}
 
 void Receiver::Setup(AudioCodingModule* acm,
@@ -138,7 +144,7 @@
   _pcmFile.Open(file_name, 32000, "wb+");
 
   _realPayloadSizeBytes = 0;
-  _playoutBuffer = new int16_t[WEBRTC_10MS_PCM_AUDIO];
+  _playoutBuffer = new int16_t[kWebRtc10MsPcmAudio];
   _frequency = playSampFreq;
   _acm = acm;
   _firstTime = true;