Introduce the TransformerHost interface

This is the first step in implementing custom codecs in SDP.

Bug: none
Change-Id: I7789478208a769eaefd58b410ae6f488c604594d
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/348662
Commit-Queue: Harald Alvestrand <hta@webrtc.org>
Reviewed-by: Tony Herre <herre@google.com>
Cr-Commit-Position: refs/heads/main@{#42171}

api/frame_transformer_interface.h

@@ -120,6 +120,18 @@ class FrameTransformerInterface : public rtc::RefCountInterface {
   ~FrameTransformerInterface() override = default;
 };
 
+// An interface implemented by classes that can host a transform.
+// Currently this is implemented by the RTCRtpSender and RTCRtpReceiver.
+class FrameTransformerHost {
+ public:
+  virtual ~FrameTransformerHost() {}
+  virtual void SetFrameTransformer(
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) = 0;
+  // TODO: bugs.webrtc.org/15929 - To be added:
+  // virtual AddIncomingMediaType(RtpCodec codec) = 0;
+  // virtual AddOutgoingMediaType(RtpCodec codec) = 0;
+};
+
 }  // namespace webrtc
 
 #endif  // API_FRAME_TRANSFORMER_INTERFACE_H_

api/rtp_receiver_interface.cc

@@ -38,7 +38,7 @@ RtpReceiverInterface::dtls_transport() const {
   return nullptr;
 }
 
-void RtpReceiverInterface::SetDepacketizerToDecoderFrameTransformer(
+void RtpReceiverInterface::SetFrameTransformer(
     rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {}
 
 }  // namespace webrtc

api/rtp_receiver_interface.h

@@ -15,8 +15,10 @@
 #define API_RTP_RECEIVER_INTERFACE_H_
 
 #include <string>
+#include <utility>
 #include <vector>
 
+#include "absl/types/optional.h"
 #include "api/crypto/frame_decryptor_interface.h"
 #include "api/dtls_transport_interface.h"
 #include "api/frame_transformer_interface.h"
@@ -44,7 +46,8 @@ class RtpReceiverObserverInterface {
   virtual ~RtpReceiverObserverInterface() {}
 };
 
-class RTC_EXPORT RtpReceiverInterface : public webrtc::RefCountInterface {
+class RTC_EXPORT RtpReceiverInterface : public webrtc::RefCountInterface,
+                                        public FrameTransformerHost {
  public:
   virtual rtc::scoped_refptr<MediaStreamTrackInterface> track() const = 0;
 
@@ -111,8 +114,17 @@ class RTC_EXPORT RtpReceiverInterface : public webrtc::RefCountInterface {
   // Sets a frame transformer between the depacketizer and the decoder to enable
   // client code to transform received frames according to their own processing
   // logic.
+  // TODO: bugs.webrtc.org/15929 - add [[deprecated("Use SetFrameTransformer")]]
+  // when usage in Chrome is removed
   virtual void SetDepacketizerToDecoderFrameTransformer(
-      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer);
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
+    SetFrameTransformer(std::move(frame_transformer));
+  }
+
+  // Default implementation of SetFrameTransformer.
+  // TODO: bugs.webrtc.org/15929 - Make pure virtual.
+  void SetFrameTransformer(
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
 
  protected:
   ~RtpReceiverInterface() override = default;

api/rtp_sender_interface.h

@@ -14,8 +14,10 @@
 #ifndef API_RTP_SENDER_INTERFACE_H_
 #define API_RTP_SENDER_INTERFACE_H_
 
+#include <cstdint>
 #include <memory>
 #include <string>
+#include <utility>
 #include <vector>
 
 #include "absl/functional/any_invocable.h"
@@ -36,7 +38,8 @@ namespace webrtc {
 
 using SetParametersCallback = absl::AnyInvocable<void(RTCError) &&>;
 
-class RTC_EXPORT RtpSenderInterface : public webrtc::RefCountInterface {
+class RTC_EXPORT RtpSenderInterface : public webrtc::RefCountInterface,
+                                      public FrameTransformerHost {
  public:
   // Returns true if successful in setting the track.
   // Fails if an audio track is set on a video RtpSender, or vice-versa.
@@ -100,8 +103,12 @@ class RTC_EXPORT RtpSenderInterface : public webrtc::RefCountInterface {
   virtual rtc::scoped_refptr<FrameEncryptorInterface> GetFrameEncryptor()
       const = 0;
 
+  // TODO: bugs.webrtc.org/15929 - add [[deprecated("Use SetFrameTransformer")]]
+  // when usage in Chrome is removed
   virtual void SetEncoderToPacketizerFrameTransformer(
-      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) = 0;
+      rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
+    SetFrameTransformer(std::move(frame_transformer));
+  }
 
   // Sets a user defined encoder selector.
   // Overrides selector that is (optionally) provided by VideoEncoderFactory.
@@ -109,6 +116,11 @@ class RTC_EXPORT RtpSenderInterface : public webrtc::RefCountInterface {
       std::unique_ptr<VideoEncoderFactory::EncoderSelectorInterface>
           encoder_selector) = 0;
 
+  // Default implementation of SetFrameTransformer.
+  // TODO: bugs.webrtc.org/15929 - remove when all implementations are good
+  void SetFrameTransformer(rtc::scoped_refptr<FrameTransformerInterface>
+                               frame_transformer) override {}
+
  protected:
   ~RtpSenderInterface() override = default;
 };

api/test/mock_rtpsender.h

@@ -63,7 +63,7 @@ class MockRtpSender : public RtpSenderInterface {
               (),
               (const, override));
   MOCK_METHOD(void,
-              SetEncoderToPacketizerFrameTransformer,
+              SetFrameTransformer,
               (rtc::scoped_refptr<FrameTransformerInterface>),
               (override));
   MOCK_METHOD(void,

pc/audio_rtp_receiver.cc

@@ -277,7 +277,7 @@ std::vector<RtpSource> AudioRtpReceiver::GetSources() const {
   return media_channel_->GetSources(current_ssrc.value());
 }
 
-void AudioRtpReceiver::SetDepacketizerToDecoderFrameTransformer(
+void AudioRtpReceiver::SetFrameTransformer(
     rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
   RTC_DCHECK_RUN_ON(worker_thread_);
   if (media_channel_) {

pc/audio_rtp_receiver.h

@@ -117,7 +117,7 @@ class AudioRtpReceiver : public ObserverInterface,
 
   std::vector<RtpSource> GetSources() const override;
   int AttachmentId() const override { return attachment_id_; }
-  void SetDepacketizerToDecoderFrameTransformer(
+  void SetFrameTransformer(
       rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
 
  private:

pc/rtp_receiver_proxy.h

@@ -45,7 +45,7 @@ PROXY_SECONDARY_METHOD1(void,
 PROXY_SECONDARY_CONSTMETHOD0(rtc::scoped_refptr<FrameDecryptorInterface>,
                              GetFrameDecryptor)
 PROXY_SECONDARY_METHOD1(void,
-                        SetDepacketizerToDecoderFrameTransformer,
+                        SetFrameTransformer,
                         rtc::scoped_refptr<FrameTransformerInterface>)
 END_PROXY_MAP(RtpReceiver)
 

pc/rtp_sender.cc

@@ -506,7 +506,7 @@ void RtpSenderBase::SetSsrc(uint32_t ssrc) {
     SetFrameEncryptor(frame_encryptor_);
   }
   if (frame_transformer_) {
-    SetEncoderToPacketizerFrameTransformer(frame_transformer_);
+    SetFrameTransformer(frame_transformer_);
   }
   if (encoder_selector_) {
     SetEncoderSelectorOnChannel();
@@ -580,7 +580,7 @@ RTCError RtpSenderBase::DisableEncodingLayers(
   return result;
 }
 
-void RtpSenderBase::SetEncoderToPacketizerFrameTransformer(
+void RtpSenderBase::SetFrameTransformer(
     rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
   RTC_DCHECK_RUN_ON(signaling_thread_);
   frame_transformer_ = std::move(frame_transformer);

pc/rtp_sender.h

@@ -206,7 +206,7 @@ class RtpSenderBase : public RtpSenderInternal, public ObserverInterface {
   // If the specified list is empty, this is a no-op.
   RTCError DisableEncodingLayers(const std::vector<std::string>& rid) override;
 
-  void SetEncoderToPacketizerFrameTransformer(
+  void SetFrameTransformer(
       rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
 
   void SetEncoderSelector(

pc/rtp_sender_proxy.h

@@ -47,7 +47,7 @@ PROXY_CONSTMETHOD0(rtc::scoped_refptr<FrameEncryptorInterface>,
                    GetFrameEncryptor)
 PROXY_METHOD1(void, SetStreams, const std::vector<std::string>&)
 PROXY_METHOD1(void,
-              SetEncoderToPacketizerFrameTransformer,
+              SetFrameTransformer,
               rtc::scoped_refptr<FrameTransformerInterface>)
 PROXY_METHOD1(void,
               SetEncoderSelector,

pc/test/mock_rtp_sender_internal.h

@@ -85,7 +85,7 @@ class MockRtpSenderInternal : public RtpSenderInternal {
               (),
               (const, override));
   MOCK_METHOD(void,
-              SetEncoderToPacketizerFrameTransformer,
+              SetFrameTransformer,
               (rtc::scoped_refptr<FrameTransformerInterface>),
               (override));
   MOCK_METHOD(void,

pc/video_rtp_receiver.cc

@@ -98,7 +98,7 @@ VideoRtpReceiver::GetFrameDecryptor() const {
   return frame_decryptor_;
 }
 
-void VideoRtpReceiver::SetDepacketizerToDecoderFrameTransformer(
+void VideoRtpReceiver::SetFrameTransformer(
     rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) {
   RTC_DCHECK_RUN_ON(worker_thread_);
   frame_transformer_ = std::move(frame_transformer);

pc/video_rtp_receiver.h

@@ -82,7 +82,7 @@ class VideoRtpReceiver : public RtpReceiverInternal {
   rtc::scoped_refptr<FrameDecryptorInterface> GetFrameDecryptor()
       const override;
 
-  void SetDepacketizerToDecoderFrameTransformer(
+  void SetFrameTransformer(
       rtc::scoped_refptr<FrameTransformerInterface> frame_transformer) override;
 
   // RtpReceiverInternal implementation.