BWE allocation strategy

webrtc/call/bitrate_allocator.cc

Index: webrtc/call/bitrate_allocator.cc
diff --git a/webrtc/call/bitrate_allocator.cc b/webrtc/call/bitrate_allocator.cc
index 2eb40b0670813c008b1b594541fc1e12147e47e9..3a1eb58c2612c9852b342a145c92f593afa84093 100644
--- a/webrtc/call/bitrate_allocator.cc
+++ b/webrtc/call/bitrate_allocator.cc
@@ -56,7 +56,8 @@ BitrateAllocator::BitrateAllocator(LimitObserver* limit_observer)
       clock_(Clock::GetRealTimeClock()),
       last_bwe_log_time_(0),
       total_requested_padding_bitrate_(0),
-      total_requested_min_bitrate_(0) {
+      total_requested_min_bitrate_(0),
+      bitrate_allocation_strategy_(nullptr) {
   sequenced_checker_.Detach();
 }
 
@@ -199,6 +200,7 @@ void BitrateAllocator::UpdateAllocationLimits() {
 
 void BitrateAllocator::RemoveObserver(BitrateAllocatorObserver* observer) {
   RTC_DCHECK_CALLED_SEQUENTIALLY(&sequenced_checker_);
+
   auto it = FindObserverConfig(observer);
   if (it != bitrate_observer_configs_.end()) {
     bitrate_observer_configs_.erase(it);
@@ -224,6 +226,12 @@ int BitrateAllocator::GetStartBitrate(BitrateAllocatorObserver* observer) {
   }
 }
 
+void BitrateAllocator::SetBitrateAllocationStrategy(
+    rtc::BitrateAllocationStrategy* bitrate_allocation_strategy) {
+  RTC_DCHECK_CALLED_SEQUENTIALLY(&sequenced_checker_);
+  bitrate_allocation_strategy_ = bitrate_allocation_strategy;
+}
+
 BitrateAllocator::ObserverConfigs::iterator
 BitrateAllocator::FindObserverConfig(const BitrateAllocatorObserver* observer) {
   RTC_DCHECK_CALLED_SEQUENTIALLY(&sequenced_checker_);
@@ -241,6 +249,25 @@ BitrateAllocator::ObserverAllocation BitrateAllocator::AllocateBitrates(
   if (bitrate_observer_configs_.empty())
     return ObserverAllocation();
 
+  if (bitrate_allocation_strategy_ != nullptr) {
+    std::vector<const rtc::BitrateAllocationStrategy::TrackConfig*>
+        track_configs(bitrate_observer_configs_.size());
+    for (auto it = bitrate_observer_configs_.begin();
+         it != bitrate_observer_configs_.end(); ++it) {
+      track_configs[it - bitrate_observer_configs_.begin()] = &*it;
+    }

[Taylor Brandstetter, 2017/09/15 01:24:41]

nit: I think a foreach style loop would still be more readable:

int i = 0;
for (const auto& c : bitrate_observer_configs_) {
  track_configs[i++] = &c;
}

Or you could even do this if you wanna be fancy:

std::transform(bitrate_observer_configs_.begin(), 
               bitrate_observer_configs_.end(),
               track_configs.begin(),
               [](const rtc::BitrateAllocationStrategy::TrackConfig& c) { return
&c; });

[alexnarest, 2017/09/15 08:29:39]

Done.

+    std::vector<uint32_t> track_allocations =
+        bitrate_allocation_strategy_->AllocateBitrates(bitrate, track_configs);
+    // The strategy should return allocation for all tracks.
+    RTC_CHECK(track_allocations.size() == bitrate_observer_configs_.size());
+    ObserverAllocation allocation;
+    auto track_allocations_it = track_allocations.begin();
+    for (const auto& observer_config : bitrate_observer_configs_) {
+      allocation[observer_config.observer] = *track_allocations_it++;
+    }
+    return allocation;
+  }
+
   if (bitrate == 0)
     return ZeroRateAllocation();