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Implement stable rate support in SimulcastRateAllocator

Browse Source 
Bug: webrtc:10126
Change-Id: I2ea8d27b0bd6f7ffd1ebbba451bd1ce1f2eee3d9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/151121
Reviewed-by: Florent Castelli <orphis@webrtc.org>
Commit-Queue: Erik Språng <sprang@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29097}
This commit is contained in:
Erik Språng
2019-09-04 16:30:47 +02:00
committed by Commit Bot
parent 059a0b7587
commit 2b9dba3d9c
9 changed files with 173 additions and 78 deletions
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91
modules/video_coding/utility/simulcast_rate_allocator.cc
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@ -59,32 +59,45 @@ float SimulcastRateAllocator::GetTemporalRateAllocation(int num_layers,
SimulcastRateAllocator::SimulcastRateAllocator(const VideoCodec& codec)
: codec_(codec),
hysteresis_factor_(RateControlSettings::ParseFromFieldTrials()
.GetSimulcastHysteresisFactor(codec.mode)) {}
stable_rate_settings_(
StableTargetRateExperiment::ParseFromFieldTrials()) {}
SimulcastRateAllocator::~SimulcastRateAllocator() = default;
VideoBitrateAllocation SimulcastRateAllocator::Allocate(
VideoBitrateAllocationParameters parameters) {
VideoBitrateAllocation allocated_bitrates_bps;
DistributeAllocationToSimulcastLayers(parameters.total_bitrate.bps(),
&allocated_bitrates_bps);
DistributeAllocationToTemporalLayers(&allocated_bitrates_bps);
return allocated_bitrates_bps;
VideoBitrateAllocation allocated_bitrates;
DataRate stable_rate = parameters.total_bitrate;
if (stable_rate_settings_.IsEnabled() &&
parameters.stable_bitrate > DataRate::Zero()) {
stable_rate = std::min(parameters.stable_bitrate, parameters.total_bitrate);
}
DistributeAllocationToSimulcastLayers(parameters.total_bitrate, stable_rate,
&allocated_bitrates);
DistributeAllocationToTemporalLayers(&allocated_bitrates);
return allocated_bitrates;
}
void SimulcastRateAllocator::DistributeAllocationToSimulcastLayers(
uint32_t total_bitrate_bps,
VideoBitrateAllocation* allocated_bitrates_bps) {
uint32_t left_to_allocate = total_bitrate_bps;
if (codec_.maxBitrate && codec_.maxBitrate * 1000 < left_to_allocate)
left_to_allocate = codec_.maxBitrate * 1000;
DataRate total_bitrate,
DataRate stable_bitrate,
VideoBitrateAllocation* allocated_bitrates) {
DataRate left_in_total_allocation = total_bitrate;
DataRate left_in_stable_allocation = stable_bitrate;
if (codec_.maxBitrate) {
DataRate max_rate = DataRate::kbps(codec_.maxBitrate);
left_in_total_allocation = std::min(left_in_total_allocation, max_rate);
left_in_stable_allocation = std::min(left_in_stable_allocation, max_rate);
}
if (codec_.numberOfSimulcastStreams == 0) {
// No simulcast, just set the target as this has been capped already.
if (codec_.active) {
allocated_bitrates_bps->SetBitrate(
0, 0, std::max(codec_.minBitrate * 1000, left_to_allocate));
allocated_bitrates->SetBitrate(
0, 0,
std::max(DataRate::kbps(codec_.minBitrate), left_in_total_allocation)
.bps());
}
return;
}
@ -115,9 +128,10 @@ void SimulcastRateAllocator::DistributeAllocationToSimulcastLayers(
// Always allocate enough bitrate for the minimum bitrate of the first
// active layer. Suspending below min bitrate is controlled outside the
// codec implementation and is not overridden by this.
left_to_allocate = std::max(
codec_.simulcastStream[layer_index[active_layer]].minBitrate * 1000,
left_to_allocate);
DataRate min_rate = DataRate::kbps(
codec_.simulcastStream[layer_index[active_layer]].minBitrate);
left_in_total_allocation = std::max(left_in_total_allocation, min_rate);
left_in_stable_allocation = std::max(left_in_stable_allocation, min_rate);
// Begin by allocating bitrate to simulcast streams, putting all bitrate in
// temporal layer 0. We'll then distribute this bitrate, across potential
@ -142,25 +156,28 @@ void SimulcastRateAllocator::DistributeAllocationToSimulcastLayers(
}
// If we can't allocate to the current layer we can't allocate to higher
// layers because they require a higher minimum bitrate.
uint32_t min_bitrate = stream.minBitrate * 1000;
DataRate min_bitrate = DataRate::kbps(stream.minBitrate);
DataRate target_bitrate = DataRate::kbps(stream.targetBitrate);
double hysteresis_factor =
codec_.mode == VideoCodecMode::kRealtimeVideo
? stable_rate_settings_.GetVideoHysteresisFactor()
: stable_rate_settings_.GetScreenshareHysteresisFactor();
if (!first_allocation && !stream_enabled_[layer_index[active_layer]]) {
min_bitrate = std::min(
static_cast<uint32_t>(hysteresis_factor_ * min_bitrate + 0.5),
stream.targetBitrate * 1000);
min_bitrate = std::min(hysteresis_factor * min_bitrate, target_bitrate);
}
if (left_to_allocate < min_bitrate) {
if (left_in_stable_allocation < min_bitrate) {
break;
}
// We are allocating to this layer so it is the current active allocation.
top_active_layer = layer_index[active_layer];
stream_enabled_[layer_index[active_layer]] = true;
uint32_t allocation =
std::min(left_to_allocate, stream.targetBitrate * 1000);
allocated_bitrates_bps->SetBitrate(layer_index[active_layer], 0,
allocation);
RTC_DCHECK_LE(allocation, left_to_allocate);
left_to_allocate -= allocation;
DataRate layer_rate = std::min(left_in_total_allocation, target_bitrate);
allocated_bitrates->SetBitrate(layer_index[active_layer], 0,
layer_rate.bps());
left_in_total_allocation -= layer_rate;
left_in_stable_allocation -=
std::min(left_in_stable_allocation, target_bitrate);
}
// All layers above this one are not active.
@ -172,16 +189,16 @@ void SimulcastRateAllocator::DistributeAllocationToSimulcastLayers(
// stream.
// TODO(sprang): Allocate up to max bitrate for all layers once we have a
// better idea of possible performance implications.
if (left_to_allocate > 0) {
if (left_in_total_allocation > DataRate::Zero()) {
const SimulcastStream& stream = codec_.simulcastStream[top_active_layer];
uint32_t bitrate_bps =
allocated_bitrates_bps->GetSpatialLayerSum(top_active_layer);
uint32_t allocation =
std::min(left_to_allocate, stream.maxBitrate * 1000 - bitrate_bps);
bitrate_bps += allocation;
RTC_DCHECK_LE(allocation, left_to_allocate);
left_to_allocate -= allocation;
allocated_bitrates_bps->SetBitrate(top_active_layer, 0, bitrate_bps);
DataRate initial_layer_rate =
DataRate::bps(allocated_bitrates->GetSpatialLayerSum(top_active_layer));
DataRate additional_allocation =
std::min(left_in_total_allocation,
DataRate::kbps(stream.maxBitrate) - initial_layer_rate);
allocated_bitrates->SetBitrate(
top_active_layer, 0,
(initial_layer_rate + additional_allocation).bps());
}
}