diff --git a/modules/rtp_rtcp/BUILD.gn b/modules/rtp_rtcp/BUILD.gn
index c66f67261e..6e3fb91ba6 100644
--- a/modules/rtp_rtcp/BUILD.gn
+++ b/modules/rtp_rtcp/BUILD.gn
@@ -45,6 +45,7 @@ rtc_source_set("rtp_rtcp_format") {
     "source/rtp_packet_to_send.h",
   ]
   sources = [
+    "include/rtp_rtcp_defines.cc",
     "source/rtcp_packet.cc",
     "source/rtcp_packet/app.cc",
     "source/rtcp_packet/bye.cc",
diff --git a/modules/rtp_rtcp/include/rtp_rtcp_defines.cc b/modules/rtp_rtcp/include/rtp_rtcp_defines.cc
new file mode 100644
index 0000000000..af3714b25e
--- /dev/null
+++ b/modules/rtp_rtcp/include/rtp_rtcp_defines.cc
@@ -0,0 +1,26 @@
+/*
+ *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
+ *
+ *  Use of this source code is governed by a BSD-style license
+ *  that can be found in the LICENSE file in the root of the source
+ *  tree. An additional intellectual property rights grant can be found
+ *  in the file PATENTS.  All contributing project authors may
+ *  be found in the AUTHORS file in the root of the source tree.
+ */
+
+#include "modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+
+namespace webrtc {
+
+PayloadUnion::PayloadUnion(const AudioPayload& payload)
+    : audio_payload_(payload) {}
+PayloadUnion::PayloadUnion(const VideoPayload& payload)
+    : video_payload_(payload) {}
+PayloadUnion::PayloadUnion(const PayloadUnion&) = default;
+PayloadUnion::PayloadUnion(PayloadUnion&&) = default;
+PayloadUnion::~PayloadUnion() = default;
+
+PayloadUnion& PayloadUnion::operator=(const PayloadUnion&) = default;
+PayloadUnion& PayloadUnion::operator=(PayloadUnion&&) = default;
+
+}  // namespace webrtc
diff --git a/modules/rtp_rtcp/include/rtp_rtcp_defines.h b/modules/rtp_rtcp/include/rtp_rtcp_defines.h
index 64980051c4..0b850fe946 100644
--- a/modules/rtp_rtcp/include/rtp_rtcp_defines.h
+++ b/modules/rtp_rtcp/include/rtp_rtcp_defines.h
@@ -53,37 +53,37 @@ struct VideoPayload {
 
 class PayloadUnion {
  public:
-  explicit PayloadUnion(const AudioPayload& payload)
-      : Audio(payload), is_audio_(true) {}
-  explicit PayloadUnion(const VideoPayload& payload)
-      : Video(payload), is_audio_(false) {}
+  explicit PayloadUnion(const AudioPayload& payload);
+  explicit PayloadUnion(const VideoPayload& payload);
+  PayloadUnion(const PayloadUnion&);
+  PayloadUnion(PayloadUnion&&);
+  ~PayloadUnion();
 
-  bool is_audio() const { return is_audio_; }
-  bool is_video() const { return !is_audio_; }
+  PayloadUnion& operator=(const PayloadUnion&);
+  PayloadUnion& operator=(PayloadUnion&&);
+
+  bool is_audio() const { return audio_payload_.has_value(); }
+  bool is_video() const { return video_payload_.has_value(); }
   const AudioPayload& audio_payload() const {
-    RTC_DCHECK(is_audio_);
-    return Audio;
+    RTC_DCHECK(audio_payload_);
+    return *audio_payload_;
   }
   const VideoPayload& video_payload() const {
-    RTC_DCHECK(!is_audio_);
-    return Video;
+    RTC_DCHECK(video_payload_);
+    return *video_payload_;
   }
   AudioPayload& audio_payload() {
-    RTC_DCHECK(is_audio_);
-    return Audio;
+    RTC_DCHECK(audio_payload_);
+    return *audio_payload_;
   }
   VideoPayload& video_payload() {
-    RTC_DCHECK(!is_audio_);
-    return Video;
+    RTC_DCHECK(video_payload_);
+    return *video_payload_;
   }
 
- public:
-  // These two are public for backwards compatibilty. They'll go private soon.
-  AudioPayload Audio;
-  VideoPayload Video;
-
  private:
-  bool is_audio_;
+  rtc::Optional<AudioPayload> audio_payload_;
+  rtc::Optional<VideoPayload> video_payload_;
 };
 
 enum RTPAliveType { kRtpDead = 0, kRtpNoRtp = 1, kRtpAlive = 2 };
diff --git a/modules/rtp_rtcp/source/rtp_utility.h b/modules/rtp_rtcp/source/rtp_utility.h
index 04eb4383d3..b71b9dca16 100644
--- a/modules/rtp_rtcp/source/rtp_utility.h
+++ b/modules/rtp_rtcp/source/rtp_utility.h
@@ -30,13 +30,11 @@ RtpFeedback* NullObjectRtpFeedback();
 namespace RtpUtility {
 
 struct Payload {
-  Payload(const char* name, const PayloadUnion& pu)
-      : audio(pu.is_audio()), typeSpecific(pu) {
+  Payload(const char* name, const PayloadUnion& pu) : typeSpecific(pu) {
     std::strncpy(this->name, name, sizeof(this->name) - 1);
     this->name[sizeof(this->name) - 1] = '\0';
   }
   char name[RTP_PAYLOAD_NAME_SIZE];
-  bool audio;
   PayloadUnion typeSpecific;
 };