Introduce RtpStreamReceiver and RtpStreamReceiverControllerInterface.

webrtc/call/rtp_stream_receiver_controller_interface.h

Index: webrtc/call/rtp_stream_receiver_controller_interface.h
diff --git a/webrtc/call/rtp_stream_receiver_controller_interface.h b/webrtc/call/rtp_stream_receiver_controller_interface.h
new file mode 100644
index 0000000000000000000000000000000000000000..51d25a525e3c26ad514d9dd0fda8d7f66c46c6f7
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+++ b/webrtc/call/rtp_stream_receiver_controller_interface.h
@@ -0,0 +1,47 @@
+/*
+ *  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.
+ */
+#ifndef WEBRTC_CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_
+#define WEBRTC_CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_
+
+#include <memory>
+
+#include "webrtc/call/rtp_packet_sink_interface.h"
+
+namespace webrtc {
+
+// An RtpStreamReceiver is responsible for the rtp-specific but
+// media-independent state needed for receiving an RTP stream.
+// TODO(nisse): Currently, only owns the association between ssrc and
+// the stream's RtpPacketSinkInterface. Ownership of corresponding
+// objects from modules/rtp_rtcp/ should move to this class (or
+// rather, the corresponding implementation class). We should add
+// methods for getting rtp receive stats, and for sending RTCP

[the sun, 2017/06/16 13:37:39]

I thought RTCP messages were usually sent for a collection of streams?

[nisse-webrtc, 2017/06/16 14:33:26]

The intended interface would like "I want a key frame for this stream", and then
the Controller should be responsible for how that gets packed into an RTCP
packet, possibly together with information from other send and receive streams.

Maybe there's some confusion between what I call an "RTCP message" (one piece of
info with precise meaning, communicted using the RTCP protocol) and an RTCP
packet (data corresponding to a single RTCP packet on the wire). Can you suggest
better wording?

+// messages related to the receive stream.
+class RtpStreamReceiverInterface {
+ public:
+  virtual ~RtpStreamReceiverInterface() {}
+};
+
+// This class acts as a factory for RtpStreamReceiver objects.
+class RtpStreamReceiverControllerInterface {
+ public:
+  virtual ~RtpStreamReceiverControllerInterface() {}
+
+  virtual std::unique_ptr<RtpStreamReceiverInterface> CreateReceiver(
+      uint32_t ssrc,
+      RtpPacketSinkInterface* sink) = 0;
+  // For registering additional sinks, needed for FlexFEC.
+  virtual void AddSink(uint32_t ssrc, RtpPacketSinkInterface* sink) = 0;
+  virtual size_t RemoveSink(const RtpPacketSinkInterface* sink) = 0;
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_CALL_RTP_STREAM_RECEIVER_CONTROLLER_INTERFACE_H_