Add FlexfecSender.

webrtc/modules/rtp_rtcp/source/flexfec_sender_impl.h

+/*
+ *  Copyright (c) 2016 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_MODULES_RTP_RTCP_SOURCE_FLEXFEC_SENDER_IMPL_H_
+#define WEBRTC_MODULES_RTP_RTCP_SOURCE_FLEXFEC_SENDER_IMPL_H_
+
+#include <memory>
+#include <vector>
+
+#include "webrtc/base/basictypes.h"
+#include "webrtc/base/random.h"
+#include "webrtc/base/sequenced_task_checker.h"
+#include "webrtc/modules/rtp_rtcp/include/flexfec_sender.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_packet_to_send.h"
+#include "webrtc/modules/rtp_rtcp/source/ulpfec_generator.h"
+#include "webrtc/system_wrappers/include/clock.h"
+
+namespace webrtc {
+
+class FlexfecSenderImpl : public FlexfecSender {
+ public:
+  FlexfecSenderImpl(int flexfec_payload_type,
+                    uint32_t flexfec_ssrc,
+                    uint32_t protected_media_ssrc,
+                    const std::vector<RtpExtension>& rtp_header_extensions,
+                    Clock* clock);
+  ~FlexfecSenderImpl();
+
+  // Implements FlexfecSender.
+  void SetFecParameters(const FecProtectionParams& params) override;
+  bool AddRtpPacketAndGenerateFec(const RtpPacketToSend& packet) override;
+  bool FecAvailable() const override;
+  std::vector<std::unique_ptr<RtpPacketToSend>> GetFecPackets() override;
+  size_t MaxPacketOverhead() const override;
+
+ private:
+  // Utility.
+  Clock* const clock_;
+  Random random_ GUARDED_BY(sequence_checker_);
+  int64_t last_generated_packet_ms_ GUARDED_BY(sequence_checker_);
+  rtc::SequencedTaskChecker sequence_checker_;
+
+  // Config.
+  const int flexfec_payload_type_;
+  const uint32_t timestamp_offset_;
+  const uint32_t flexfec_ssrc_;
+  const uint32_t protected_media_ssrc_;
+  // Sequence number of next packet to generate.
+  uint16_t seq_num_ GUARDED_BY(sequence_checker_);
+
+  // Implementation.
+  UlpfecGenerator ulpfec_generator_ GUARDED_BY(sequence_checker_);
+  RtpHeaderExtensionMap rtp_header_extension_map_ GUARDED_BY(sequence_checker_);
+};
+
+}  // namespace webrtc
+
+#endif  // WEBRTC_MODULES_RTP_RTCP_SOURCE_FLEXFEC_SENDER_IMPL_H_