Add sender controlled playout delay limits

webrtc/modules/rtp_rtcp/source/playout_delay_oracle.cc

Index: webrtc/modules/rtp_rtcp/source/playout_delay_oracle.cc
diff --git a/webrtc/modules/rtp_rtcp/source/playout_delay_oracle.cc b/webrtc/modules/rtp_rtcp/source/playout_delay_oracle.cc
new file mode 100644
index 0000000000000000000000000000000000000000..ed3af3f2c4aca2126a56325892b841119cae195c
--- /dev/null
+++ b/webrtc/modules/rtp_rtcp/source/playout_delay_oracle.cc
@@ -0,0 +1,68 @@
+/*
+ *  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.
+ */
+
+#include "webrtc/modules/rtp_rtcp/source/playout_delay_oracle.h"
+
+#include "webrtc/base/checks.h"
+#include "webrtc/base/logging.h"
+#include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
+#include "webrtc/modules/rtp_rtcp/source/rtp_header_extension.h"
+
+namespace webrtc {
+
+PlayoutDelayOracle::PlayoutDelayOracle()
+    : high_sequence_number_(0),
+      send_playout_delay_(false),
+      ssrc_(0),
+      min_playout_delay_ms_(-1),
+      max_playout_delay_ms_(-1) {
+  thread_checker_.DetachFromThread();
+}
+PlayoutDelayOracle::~PlayoutDelayOracle() {}
+
+void PlayoutDelayOracle::UpdateRequest(uint32_t ssrc,
+                                       PlayoutDelay playout_delay,
+                                       uint16_t seq_num) {
+  rtc::CritScope lock(&crit_sect_);
+  RTC_DCHECK_RUN_ON(&thread_checker_);
+  RTC_DCHECK_LE(playout_delay.min_ms, kPlayoutDelayMaxMs);
+  RTC_DCHECK_LE(playout_delay.max_ms, kPlayoutDelayMaxMs);
+  RTC_DCHECK_LE(playout_delay.min_ms, playout_delay.max_ms);
+  int64_t unwrapped_seq_num = unwrapper_.Unwrap(seq_num);
+  if (playout_delay.min_ms >= 0 &&
+      playout_delay.min_ms != min_playout_delay_ms_) {
+    send_playout_delay_ = true;
+    min_playout_delay_ms_ = playout_delay.min_ms;
+    high_sequence_number_ = unwrapped_seq_num;
+  }
+
+  if (playout_delay.max_ms >= 0 &&
+      playout_delay.max_ms != max_playout_delay_ms_) {
+    send_playout_delay_ = true;
+    max_playout_delay_ms_ = playout_delay.max_ms;
+    high_sequence_number_ = unwrapped_seq_num;
+  }
+  ssrc_ = ssrc;
+}
+
+// If an ACK is received on the packet containing the playout delay extension,
+// we stop sending the extension on future packets.
+void PlayoutDelayOracle::OnReceivedRtcpReportBlocks(
+    const ReportBlockList& report_blocks) {
+  rtc::CritScope lock(&crit_sect_);
+  for (const RTCPReportBlock& report_block : report_blocks) {
+    if ((ssrc_ == report_block.sourceSSRC) && send_playout_delay_ &&
+        (report_block.extendedHighSeqNum > high_sequence_number_)) {
+      send_playout_delay_ = false;
+    }
+  }
+}
+
+}  // namespace webrtc