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Simulcast screenshare adjustment to temporal layers, bitrate

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Change experimental max bitrate setting from 1.6Mbps to 1.25Mbps in
order to allow a larger fraction of participants to receive this layer.

Add a new field trial to allow setting the number of temporal layers for
the high-quality simulcast stream in screensharing separately from the
temporal layer count for regular video.

Bug: webrtc:9477
Change-Id: I1341b774f870c50710901da24963bd3ede96ffd8
Reviewed-on: https://webrtc-review.googlesource.com/95101
Commit-Queue: Erik Språng <sprang@webrtc.org>
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#24356}
This commit is contained in:
Erik Språng
2018-08-21 13:15:28 +02:00
committed by Commit Bot
parent 76be29555d
commit 58b228461d
1 changed files with 12 additions and 10 deletions
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22
media/engine/simulcast.cc
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@ -31,7 +31,7 @@ constexpr int kScreenshareDefaultTl1BitrateKbps = 1000;
// Max bitrate for the higher one of the two simulcast stream used for screen
// content.
constexpr int kScreenshareHighStreamMaxBitrateBps = 1600000;
constexpr int kScreenshareHighStreamMaxBitrateBps = 1250000;
} // namespace
@ -70,14 +70,17 @@ const SimulcastFormat kSimulcastFormats[] = {
const int kMaxScreenshareSimulcastLayers = 2;
// Multiway: Number of temporal layers for each simulcast stream.
int DefaultNumberOfTemporalLayers(int simulcast_id) {
int DefaultNumberOfTemporalLayers(int simulcast_id, bool screenshare) {
RTC_CHECK_GE(simulcast_id, 0);
RTC_CHECK_LT(simulcast_id, webrtc::kMaxSimulcastStreams);
const int kDefaultNumTemporalLayers = 3;
const std::string group_name =
webrtc::field_trial::FindFullName("WebRTC-VP8ConferenceTemporalLayers");
screenshare ? webrtc::field_trial::FindFullName(
"WebRTC-VP8ScreenshareTemporalLayers")
: webrtc::field_trial::FindFullName(
"WebRTC-VP8ConferenceTemporalLayers");
if (group_name.empty())
return kDefaultNumTemporalLayers;
@ -240,11 +243,10 @@ std::vector<webrtc::VideoStream> GetNormalSimulcastLayers(
// TODO(pbos): Fill actual temporal-layer bitrate thresholds.
layers[s].max_qp = max_qp;
layers[s].num_temporal_layers =
temporal_layers_supported ? DefaultNumberOfTemporalLayers(s)
: 0;
temporal_layers_supported ? DefaultNumberOfTemporalLayers(s, false) : 0;
layers[s].max_bitrate_bps = FindSimulcastMaxBitrateBps(width, height);
layers[s].target_bitrate_bps = FindSimulcastTargetBitrateBps(width, height);
int num_temporal_layers = DefaultNumberOfTemporalLayers(s);
int num_temporal_layers = DefaultNumberOfTemporalLayers(s, false);
if (s == 0) {
// If alternative number temporal layers is selected, adjust the
// bitrate of the lowest simulcast stream so that absolute bitrate for
@ -317,16 +319,16 @@ std::vector<webrtc::VideoStream> GetScreenshareLayers(
// restrictions. The base simulcast layer will still use legacy setup.
if (num_simulcast_layers == kMaxScreenshareSimulcastLayers) {
// Add optional upper simulcast layer.
const int num_temporal_layers = DefaultNumberOfTemporalLayers(1);
const int num_temporal_layers = DefaultNumberOfTemporalLayers(1, true);
int max_bitrate_bps;
if (!temporal_layers_supported) {
// Set the max bitrate to where the base layer would have been if temporal
// layer were enabled.
// layers were enabled.
max_bitrate_bps = static_cast<int>(
kScreenshareHighStreamMaxBitrateBps *
webrtc::SimulcastRateAllocator::GetTemporalRateAllocation(
num_temporal_layers, 0));
} else if (DefaultNumberOfTemporalLayers(1) != 3 ||
} else if (DefaultNumberOfTemporalLayers(1, true) != 3 ||
webrtc::field_trial::IsEnabled("WebRTC-UseShortVP8TL3Pattern")) {
// Experimental temporal layer mode used, use increased max bitrate.
max_bitrate_bps = kScreenshareHighStreamMaxBitrateBps;
@ -348,7 +350,7 @@ std::vector<webrtc::VideoStream> GetScreenshareLayers(
layers[1].max_qp = max_qp;
layers[1].max_framerate = max_framerate;
layers[1].num_temporal_layers =
temporal_layers_supported ? DefaultNumberOfTemporalLayers(1) : 0;
temporal_layers_supported ? DefaultNumberOfTemporalLayers(1, true) : 0;
layers[1].min_bitrate_bps = layers[0].target_bitrate_bps * 2;
layers[1].target_bitrate_bps = max_bitrate_bps;
layers[1].max_bitrate_bps = max_bitrate_bps;