diff --git a/webrtc/base/array_view.h b/webrtc/base/array_view.h
index a7ca66cc95..868009631f 100644
--- a/webrtc/base/array_view.h
+++ b/webrtc/base/array_view.h
@@ -56,6 +56,7 @@ namespace rtc {
 //   Contains17(arr);                             // C array
 //   Contains17(arr);                             // std::vector
 //   Contains17(rtc::ArrayView<int>(arr, size));  // pointer + size
+//   Contains17(nullptr);                         // nullptr -> empty ArrayView
 //   ...
 //
 // One important point is that ArrayView<T> and ArrayView<const T> are
@@ -73,6 +74,7 @@ class ArrayView final {
  public:
   // Construct an empty ArrayView.
   ArrayView() : ArrayView(static_cast<T*>(nullptr), 0) {}
+  ArrayView(std::nullptr_t) : ArrayView() {}
 
   // Construct an ArrayView for a (pointer,size) pair.
   template <typename U>
diff --git a/webrtc/modules/audio_coding/acm2/codec_manager.cc b/webrtc/modules/audio_coding/acm2/codec_manager.cc
index 81adf81a83..f028c45f99 100644
--- a/webrtc/modules/audio_coding/acm2/codec_manager.cc
+++ b/webrtc/modules/audio_coding/acm2/codec_manager.cc
@@ -113,7 +113,7 @@ bool CodecManager::RegisterEncoder(const CodecInst& send_codec) {
   }
 
   send_codec_inst_ = rtc::Optional<CodecInst>(send_codec);
-  codec_stack_params_.speech_encoder.reset();  // Caller must recreate it.
+  recreate_encoder_ = true;  // Caller must recreate it.
   return true;
 }
 
@@ -190,5 +190,67 @@ bool CodecManager::SetCodecFEC(bool enable_codec_fec) {
   return true;
 }
 
+bool CodecManager::MakeEncoder(RentACodec* rac, AudioCodingModule* acm) {
+  RTC_DCHECK(rac);
+  RTC_DCHECK(acm);
+
+  if (!recreate_encoder_) {
+    bool error = false;
+    // Try to re-use the speech encoder we've given to the ACM.
+    acm->ModifyEncoder([&](std::unique_ptr<AudioEncoder>* encoder) {
+      if (!*encoder) {
+        // There is no existing encoder.
+        recreate_encoder_ = true;
+        return;
+      }
+
+      // Extract the speech encoder from the ACM.
+      std::unique_ptr<AudioEncoder> enc = std::move(*encoder);
+      while (true) {
+        auto sub_enc = enc->ReclaimContainedEncoders();
+        if (sub_enc.empty()) {
+          break;
+        }
+        RTC_CHECK_EQ(1u, sub_enc.size());
+
+        // Replace enc with its sub encoder. We need to put the sub encoder in
+        // a temporary first, since otherwise the old value of enc would be
+        // destroyed before the new value got assigned, which would be bad
+        // since the new value is a part of the old value.
+        auto tmp_enc = std::move(sub_enc[0]);
+        enc = std::move(tmp_enc);
+      }
+
+      // Wrap it in a new encoder stack and put it back.
+      codec_stack_params_.speech_encoder = std::move(enc);
+      *encoder = rac->RentEncoderStack(&codec_stack_params_);
+      if (!*encoder) {
+        error = true;
+      }
+    });
+    if (error) {
+      return false;
+    }
+    if (!recreate_encoder_) {
+      return true;
+    }
+  }
+
+  if (!send_codec_inst_) {
+    // We don't have the information we need to create a new speech encoder.
+    // (This is not an error.)
+    return true;
+  }
+
+  codec_stack_params_.speech_encoder = rac->RentEncoder(*send_codec_inst_);
+  auto stack = rac->RentEncoderStack(&codec_stack_params_);
+  if (!stack) {
+    return false;
+  }
+  acm->SetEncoder(std::move(stack));
+  recreate_encoder_ = false;
+  return true;
+}
+
 }  // namespace acm2
 }  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/acm2/codec_manager.h b/webrtc/modules/audio_coding/acm2/codec_manager.h
index f6c6cd46d2..b60b7e7bcb 100644
--- a/webrtc/modules/audio_coding/acm2/codec_manager.h
+++ b/webrtc/modules/audio_coding/acm2/codec_manager.h
@@ -59,31 +59,13 @@ class CodecManager final {
   // Uses the provided Rent-A-Codec to create a new encoder stack, if we have a
   // complete specification; if so, it is then passed to set_encoder. On error,
   // returns false.
-  bool MakeEncoder(RentACodec* rac, AudioCodingModule* acm) {
-    RTC_DCHECK(rac);
-    RTC_DCHECK(acm);
-    if (!codec_stack_params_.speech_encoder && send_codec_inst_) {
-      // We have no speech encoder, but we have a specification for making one.
-      auto enc = rac->RentEncoder(*send_codec_inst_);
-      if (!enc)
-        return false;
-      codec_stack_params_.speech_encoder = std::move(enc);
-    }
-    auto stack = rac->RentEncoderStack(&codec_stack_params_);
-    if (stack) {
-      // Give new encoder stack to the ACM.
-      acm->SetEncoder(std::move(stack));
-    } else {
-      // The specification was good but incomplete, so we have no encoder stack
-      // to give to the ACM.
-    }
-    return true;
-  }
+  bool MakeEncoder(RentACodec* rac, AudioCodingModule* acm);
 
  private:
   rtc::ThreadChecker thread_checker_;
   rtc::Optional<CodecInst> send_codec_inst_;
   RentACodec::StackParameters codec_stack_params_;
+  bool recreate_encoder_ = true;  // Need to recreate encoder?
 
   RTC_DISALLOW_COPY_AND_ASSIGN(CodecManager);
 };
diff --git a/webrtc/modules/audio_coding/codecs/audio_encoder.cc b/webrtc/modules/audio_coding/codecs/audio_encoder.cc
index 000371d28a..6b7f5f893f 100644
--- a/webrtc/modules/audio_coding/codecs/audio_encoder.cc
+++ b/webrtc/modules/audio_coding/codecs/audio_encoder.cc
@@ -60,4 +60,7 @@ void AudioEncoder::SetProjectedPacketLossRate(double fraction) {}
 
 void AudioEncoder::SetTargetBitrate(int target_bps) {}
 
+rtc::ArrayView<std::unique_ptr<AudioEncoder>>
+AudioEncoder::ReclaimContainedEncoders() { return nullptr; }
+
 }  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/codecs/audio_encoder.h b/webrtc/modules/audio_coding/codecs/audio_encoder.h
index f4c5794d92..ecc28d96a1 100644
--- a/webrtc/modules/audio_coding/codecs/audio_encoder.h
+++ b/webrtc/modules/audio_coding/codecs/audio_encoder.h
@@ -149,6 +149,15 @@ class AudioEncoder {
   // implementation does the latter).
   virtual void SetTargetBitrate(int target_bps);
 
+  // Causes this encoder to let go of any other encoders it contains, and
+  // returns a pointer to an array where they are stored (which is required to
+  // live as long as this encoder). Unless the returned array is empty, you may
+  // not call any methods on this encoder afterwards, except for the
+  // destructor. The default implementation just returns an empty array.
+  // NOTE: This method is subject to change. Do not call or override it.
+  virtual rtc::ArrayView<std::unique_ptr<AudioEncoder>>
+  ReclaimContainedEncoders();
+
  protected:
   // Subclasses implement this to perform the actual encoding. Called by
   // Encode().
diff --git a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
index 09c25d9616..d2edcb5c26 100644
--- a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
+++ b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.cc
@@ -187,6 +187,11 @@ void AudioEncoderCng::SetTargetBitrate(int bits_per_second) {
   speech_encoder_->SetTargetBitrate(bits_per_second);
 }
 
+rtc::ArrayView<std::unique_ptr<AudioEncoder>>
+AudioEncoderCng::ReclaimContainedEncoders() {
+  return rtc::ArrayView<std::unique_ptr<AudioEncoder>>(&speech_encoder_, 1);
+}
+
 AudioEncoder::EncodedInfo AudioEncoderCng::EncodePassive(
     size_t frames_to_encode,
     rtc::Buffer* encoded) {
diff --git a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.h b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.h
index 246e9519da..a895e69de4 100644
--- a/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.h
+++ b/webrtc/modules/audio_coding/codecs/cng/audio_encoder_cng.h
@@ -63,6 +63,8 @@ class AudioEncoderCng final : public AudioEncoder {
   void SetMaxPlaybackRate(int frequency_hz) override;
   void SetProjectedPacketLossRate(double fraction) override;
   void SetTargetBitrate(int target_bps) override;
+  rtc::ArrayView<std::unique_ptr<AudioEncoder>> ReclaimContainedEncoders()
+      override;
 
  private:
   EncodedInfo EncodePassive(size_t frames_to_encode,
diff --git a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.cc b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.cc
index 7c48c0c60e..37fa55a4da 100644
--- a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.cc
+++ b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.cc
@@ -123,4 +123,9 @@ void AudioEncoderCopyRed::SetTargetBitrate(int bits_per_second) {
   speech_encoder_->SetTargetBitrate(bits_per_second);
 }
 
+rtc::ArrayView<std::unique_ptr<AudioEncoder>>
+AudioEncoderCopyRed::ReclaimContainedEncoders() {
+  return rtc::ArrayView<std::unique_ptr<AudioEncoder>>(&speech_encoder_, 1);
+}
+
 }  // namespace webrtc
diff --git a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.h b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.h
index ead9fd65a2..a08118364c 100644
--- a/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.h
+++ b/webrtc/modules/audio_coding/codecs/red/audio_encoder_copy_red.h
@@ -51,6 +51,8 @@ class AudioEncoderCopyRed final : public AudioEncoder {
   void SetMaxPlaybackRate(int frequency_hz) override;
   void SetProjectedPacketLossRate(double fraction) override;
   void SetTargetBitrate(int target_bps) override;
+  rtc::ArrayView<std::unique_ptr<AudioEncoder>> ReclaimContainedEncoders()
+      override;
 
  protected:
   EncodedInfo EncodeImpl(uint32_t rtp_timestamp,