1 files changed, 93 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/video_coding/utility/simulcast_utility.cc b/third_party/libwebrtc/modules/video_coding/utility/simulcast_utility.cc
new file mode 100644
index 0000000000..65061ed32a
--- /dev/null
+++ b/third_party/libwebrtc/modules/video_coding/utility/simulcast_utility.cc
@@ -0,0 +1,93 @@
+/*
+ *  Copyright (c) 2018 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 "modules/video_coding/utility/simulcast_utility.h"
+
+#include <algorithm>
+#include <cmath>
+
+#include "rtc_base/checks.h"
+
+namespace webrtc {
+
+uint32_t SimulcastUtility::SumStreamMaxBitrate(int streams,
+                                               const VideoCodec& codec) {
+  uint32_t bitrate_sum = 0;
+  for (int i = 0; i < streams; ++i) {
+    bitrate_sum += codec.simulcastStream[i].maxBitrate;
+  }
+  return bitrate_sum;
+}
+
+int SimulcastUtility::NumberOfSimulcastStreams(const VideoCodec& codec) {
+  int streams =
+      codec.numberOfSimulcastStreams < 1 ? 1 : codec.numberOfSimulcastStreams;
+  uint32_t simulcast_max_bitrate = SumStreamMaxBitrate(streams, codec);
+  if (simulcast_max_bitrate == 0) {
+    streams = 1;
+  }
+  return streams;
+}
+
+bool SimulcastUtility::ValidSimulcastParameters(const VideoCodec& codec,
+                                                int num_streams) {
+  // Check resolution.
+  if (codec.width != codec.simulcastStream[num_streams - 1].width ||
+      codec.height != codec.simulcastStream[num_streams - 1].height) {
+    return false;
+  }
+  for (int i = 0; i < num_streams; ++i) {
+    if (codec.width * codec.simulcastStream[i].height !=
+        codec.height * codec.simulcastStream[i].width) {
+      return false;
+    }
+  }
+  for (int i = 1; i < num_streams; ++i) {
+    if (codec.simulcastStream[i].width < codec.simulcastStream[i - 1].width) {
+      return false;
+    }
+  }
+
+  // Check frame-rate.
+  for (int i = 1; i < num_streams; ++i) {
+    if (fabs(codec.simulcastStream[i].maxFramerate -
+             codec.simulcastStream[i - 1].maxFramerate) > 1e-9) {
+      return false;
+    }
+  }
+
+  // Check temporal layers.
+  for (int i = 0; i < num_streams - 1; ++i) {
+    if (codec.simulcastStream[i].numberOfTemporalLayers !=
+        codec.simulcastStream[i + 1].numberOfTemporalLayers)
+      return false;
+  }
+  return true;
+}
+
+bool SimulcastUtility::IsConferenceModeScreenshare(const VideoCodec& codec) {
+  return codec.mode == VideoCodecMode::kScreensharing &&
+         codec.legacy_conference_mode;
+}
+
+int SimulcastUtility::NumberOfTemporalLayers(const VideoCodec& codec,
+                                             int spatial_id) {
+  uint8_t num_temporal_layers =
+      std::max<uint8_t>(1, codec.VP8().numberOfTemporalLayers);
+  if (codec.numberOfSimulcastStreams > 0) {
+    RTC_DCHECK_LT(spatial_id, codec.numberOfSimulcastStreams);
+    num_temporal_layers =
+        std::max(num_temporal_layers,
+                 codec.simulcastStream[spatial_id].numberOfTemporalLayers);
+  }
+  return num_temporal_layers;
+}
+
+}  // namespace webrtc