diff --git a/api/frame_transformer_interface.h b/api/frame_transformer_interface.h
index bfe3b0235b..d4b09a46e2 100644
--- a/api/frame_transformer_interface.h
+++ b/api/frame_transformer_interface.h
@@ -68,11 +68,11 @@ class TransformableAudioFrameInterface : public TransformableFrameInterface {
  public:
   virtual ~TransformableAudioFrameInterface() = default;
 
+  virtual void SetRTPTimestamp(uint32_t timestamp) = 0;
   // Exposes the frame header, enabling the interface clients to use the
   // information in the header as needed, for example to compile the list of
   // csrcs.
   virtual const RTPHeader& GetHeader() const = 0;
-  virtual void SetRTPTimestamp(uint32_t timestamp) { RTC_CHECK_NOTREACHED(); }
 
   virtual rtc::ArrayView<const uint32_t> GetContributingSources() const = 0;
 };
diff --git a/api/test/mock_transformable_audio_frame.h b/api/test/mock_transformable_audio_frame.h
index c8d24f079d..912488adbc 100644
--- a/api/test/mock_transformable_audio_frame.h
+++ b/api/test/mock_transformable_audio_frame.h
@@ -20,11 +20,11 @@ class MockTransformableAudioFrame : public TransformableAudioFrameInterface {
  public:
   MOCK_METHOD(rtc::ArrayView<const uint8_t>, GetData, (), (const, override));
   MOCK_METHOD(void, SetData, (rtc::ArrayView<const uint8_t>), (override));
+  MOCK_METHOD(void, SetRTPTimestamp, (uint32_t), (override));
   MOCK_METHOD(uint8_t, GetPayloadType, (), (const, override));
   MOCK_METHOD(uint32_t, GetSsrc, (), (const, override));
   MOCK_METHOD(uint32_t, GetTimestamp, (), (const, override));
   MOCK_METHOD(RTPHeader&, GetHeader, (), (const override));
-  MOCK_METHOD(void, SetRTPTimestamp, (uint32_t), (override));
   MOCK_METHOD(rtc::ArrayView<const uint32_t>,
               GetContributingSources,
               (),