Revert of Work on flexible mode and screen sharing.

webrtc/modules/video_coding/codecs/vp9/screenshare_layers.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 <algorithm>
-#include "webrtc/modules/video_coding/codecs/vp9/screenshare_layers.h"
-#include "webrtc/base/checks.h"
-
-namespace webrtc {
-
-ScreenshareLayersVP9::ScreenshareLayersVP9(uint8_t num_layers)
-    : num_layers_(num_layers),
-      start_layer_(0),
-      last_timestamp_(0),
-      timestamp_initialized_(false) {
-  RTC_DCHECK_GT(num_layers, 0);
-  RTC_DCHECK_LE(num_layers, kMaxVp9NumberOfSpatialLayers);
-  memset(bits_used_, 0, sizeof(bits_used_));
-  memset(threshold_kbps_, 0, sizeof(threshold_kbps_));
-}
-
-uint8_t ScreenshareLayersVP9::GetStartLayer() const {
-  return start_layer_;
-}
-
-void ScreenshareLayersVP9::ConfigureBitrate(int threshold_kbps,
-                                            uint8_t layer_id) {
-  // The upper layer is always the layer we spill frames
-  // to when the bitrate becomes to high, therefore setting
-  // a max limit is not allowed. The top layer bitrate is
-  // never used either so configuring it makes no difference.
-  RTC_DCHECK_LT(layer_id, num_layers_ - 1);
-  threshold_kbps_[layer_id] = threshold_kbps;
-}
-
-void ScreenshareLayersVP9::LayerFrameEncoded(unsigned int size_bytes,
-                                             uint8_t layer_id) {
-  RTC_DCHECK_LT(layer_id, num_layers_);
-  bits_used_[layer_id] += size_bytes * 8;
-}
-
-VP9EncoderImpl::SuperFrameRefSettings
-ScreenshareLayersVP9::GetSuperFrameSettings(uint32_t timestamp,
-                                            bool is_keyframe) {
-  VP9EncoderImpl::SuperFrameRefSettings settings;
-  if (!timestamp_initialized_) {
-    last_timestamp_ = timestamp;
-    timestamp_initialized_ = true;
-  }
-  float time_diff = (timestamp - last_timestamp_) / 90.f;
-  float total_bits_used = 0;
-  float total_threshold_kbps = 0;
-  start_layer_ = 0;
-
-  // Up to (num_layers - 1) because we only have
-  // (num_layers - 1) thresholds to check.
-  for (int layer_id = 0; layer_id < num_layers_ - 1; ++layer_id) {
-    bits_used_[layer_id] = std::max(
-        0.f, bits_used_[layer_id] - time_diff * threshold_kbps_[layer_id]);
-    total_bits_used += bits_used_[layer_id];
-    total_threshold_kbps += threshold_kbps_[layer_id];
-
-    // If this is a keyframe then there should be no
-    // references to any previous frames.
-    if (!is_keyframe) {
-      settings.layer[layer_id].ref_buf1 = layer_id;
-      if (total_bits_used > total_threshold_kbps * 1000)
-        start_layer_ = layer_id + 1;
-    }
-
-    settings.layer[layer_id].upd_buf = layer_id;
-  }
-  // Since the above loop does not iterate over the last layer
-  // the reference of the last layer has to be set after the loop,
-  // and if this is a keyframe there should be no references to
-  // any previous frames.
-  if (!is_keyframe)
-    settings.layer[num_layers_ - 1].ref_buf1 = num_layers_ - 1;
-
-  settings.layer[num_layers_ - 1].upd_buf = num_layers_ - 1;
-  settings.is_keyframe = is_keyframe;
-  settings.start_layer = start_layer_;
-  settings.stop_layer = num_layers_ - 1;
-  last_timestamp_ = timestamp;
-  return settings;
-}
-
-}  // namespace webrtc