Add PacketRouter::SetMaxDesiredReceiveBitrate for application limited receive bandwidth

webrtc/modules/pacing/packet_router.cc

 /*
  *  Copyright (c) 2015 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/pacing/packet_router.h"
 
+#include <algorithm>
+#include <limits>
+
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp.h"
 #include "webrtc/modules/rtp_rtcp/include/rtp_rtcp_defines.h"
 #include "webrtc/modules/rtp_rtcp/source/rtcp_packet/transport_feedback.h"
 #include "webrtc/rtc_base/atomicops.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/timeutils.h"
 
 namespace webrtc {
+namespace {
+
+constexpr int kRembSendIntervalMs = 200;
+
+}  // namespace
 
 PacketRouter::PacketRouter()
     : last_remb_time_ms_(rtc::TimeMillis()),
       last_send_bitrate_bps_(0),
+      bitrate_bps_(0),
+      max_bitrate_bps_(std::numeric_limits<decltype(max_bitrate_bps_)>::max()),
       active_remb_module_(nullptr),
       transport_seq_(0) {}
 
 PacketRouter::~PacketRouter() {
   RTC_DCHECK(rtp_send_modules_.empty());
   RTC_DCHECK(rtp_receive_modules_.empty());
   RTC_DCHECK(sender_remb_candidates_.empty());
   RTC_DCHECK(receiver_remb_candidates_.empty());
   RTC_DCHECK(active_remb_module_ == nullptr);
 }
@@ skipping 100 matching lines @@
     // return value saves us a load on retry.
     prev_seq = rtc::AtomicOps::CompareAndSwap(&transport_seq_, desired_prev_seq,
                                               new_seq);
   } while (prev_seq != desired_prev_seq);
 
   return new_seq;
 }
 
 void PacketRouter::OnReceiveBitrateChanged(const std::vector<uint32_t>& ssrcs,
                                            uint32_t bitrate_bps) {
-  const int kRembSendIntervalMs = 200;
-
   // % threshold for if we should send a new REMB asap.
   const uint32_t kSendThresholdPercent = 97;
 
   int64_t now_ms = rtc::TimeMillis();
   {
     rtc::CritScope lock(&remb_crit_);
 
     // If we already have an estimate, check if the new total estimate is below
     // kSendThresholdPercent of the previous estimate.
     if (last_send_bitrate_bps_ > 0) {
       uint32_t new_remb_bitrate_bps =
           last_send_bitrate_bps_ - bitrate_bps_ + bitrate_bps;
 
       if (new_remb_bitrate_bps <
           kSendThresholdPercent * last_send_bitrate_bps_ / 100) {
         // The new bitrate estimate is less than kSendThresholdPercent % of the
         // last report. Send a REMB asap.
         last_remb_time_ms_ = now_ms - kRembSendIntervalMs;
       }
     }
     bitrate_bps_ = bitrate_bps;
 
     if (now_ms - last_remb_time_ms_ < kRembSendIntervalMs) {
       return;
     }
     // NOTE: Updated if we intend to send the data; we might not have
     // a module to actually send it.
     last_remb_time_ms_ = now_ms;
     last_send_bitrate_bps_ = bitrate_bps;
+    // Cap the value to send in remb with configured value.
+    bitrate_bps = std::min(bitrate_bps, max_bitrate_bps_);
   }
   SendRemb(bitrate_bps, ssrcs);
 }
 
+void PacketRouter::SetMaxDesiredReceiveBitrate(uint32_t bitrate_bps) {
+  {
+    rtc::CritScope lock(&remb_crit_);
+    max_bitrate_bps_ = bitrate_bps;
+    if (rtc::TimeMillis() - last_remb_time_ms_ < kRembSendIntervalMs &&
+        last_send_bitrate_bps_ > 0 &&
+        last_send_bitrate_bps_ <= max_bitrate_bps_) {
+      // Recent measured bitrate is already below the cap.
+      return;
+    }
+  }
+  SendRemb(bitrate_bps, /*ssrcs=*/{});
+}
+
 bool PacketRouter::SendRemb(uint32_t bitrate_bps,
                             const std::vector<uint32_t>& ssrcs) {
   rtc::CritScope lock(&modules_crit_);
 
   if (!active_remb_module_) {
     return false;
   }
 
   // The Add* and Remove* methods above ensure that this (and only this) module
   // has REMB enabled. REMB should be disabled on all other modules, because
@@ skipping 80 matching lines @@
     if (new_active_remb_module_) {
       RTC_DCHECK(!new_active_remb_module_->REMB());
       new_active_remb_module_->SetREMBStatus(true);
     }
   }
 
   active_remb_module_ = new_active_remb_module_;
 }
 
 }  // namespace webrtc