modules/video_coding refactorings

webrtc/modules/video_coding/main/source/qm_select.cc

Index: webrtc/modules/video_coding/main/source/qm_select.cc
diff --git a/webrtc/modules/video_coding/main/source/qm_select.cc b/webrtc/modules/video_coding/main/source/qm_select.cc
deleted file mode 100644
index be8fcfc122edabdbef58138304fc312d88decb90..0000000000000000000000000000000000000000
--- a/webrtc/modules/video_coding/main/source/qm_select.cc
+++ /dev/null
@@ -1,958 +0,0 @@
-/*
- *  Copyright (c) 2012 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 "webrtc/modules/video_coding/main/source/qm_select.h"
-
-#include <math.h>
-
-#include "webrtc/modules/include/module_common_types.h"
-#include "webrtc/modules/video_coding/main/interface/video_coding_defines.h"
-#include "webrtc/modules/video_coding/main/source/internal_defines.h"
-#include "webrtc/modules/video_coding/main/source/qm_select_data.h"
-#include "webrtc/system_wrappers/include/trace.h"
-
-namespace webrtc {
-
-// QM-METHOD class
-
-VCMQmMethod::VCMQmMethod()
-    : content_metrics_(NULL),
-      width_(0),
-      height_(0),
-      user_frame_rate_(0.0f),
-      native_width_(0),
-      native_height_(0),
-      native_frame_rate_(0.0f),
-      image_type_(kVGA),
-      framerate_level_(kFrameRateHigh),
-      init_(false) {
-  ResetQM();
-}
-
-VCMQmMethod::~VCMQmMethod() {
-}
-
-void VCMQmMethod::ResetQM() {
-  aspect_ratio_ = 1.0f;
-  motion_.Reset();
-  spatial_.Reset();
-  content_class_ = 0;
-}
-
-uint8_t VCMQmMethod::ComputeContentClass() {
-  ComputeMotionNFD();
-  ComputeSpatial();
-  return content_class_ = 3 * motion_.level + spatial_.level;
-}
-
-void VCMQmMethod::UpdateContent(const VideoContentMetrics*  contentMetrics) {
-  content_metrics_ = contentMetrics;
-}
-
-void VCMQmMethod::ComputeMotionNFD() {
-  if (content_metrics_) {
-    motion_.value = content_metrics_->motion_magnitude;
-  }
-  // Determine motion level.
-  if (motion_.value < kLowMotionNfd) {
-    motion_.level = kLow;
-  } else if (motion_.value > kHighMotionNfd) {
-    motion_.level  = kHigh;
-  } else {
-    motion_.level = kDefault;
-  }
-}
-
-void VCMQmMethod::ComputeSpatial() {
-  float spatial_err = 0.0;
-  float spatial_err_h = 0.0;
-  float spatial_err_v = 0.0;
-  if (content_metrics_) {
-    spatial_err =  content_metrics_->spatial_pred_err;
-    spatial_err_h = content_metrics_->spatial_pred_err_h;
-    spatial_err_v = content_metrics_->spatial_pred_err_v;
-  }
-  // Spatial measure: take average of 3 prediction errors.
-  spatial_.value = (spatial_err + spatial_err_h + spatial_err_v) / 3.0f;
-
-  // Reduce thresholds for large scenes/higher pixel correlation.
-  float scale2 = image_type_ > kVGA ? kScaleTexture : 1.0;
-
-  if (spatial_.value > scale2 * kHighTexture) {
-    spatial_.level = kHigh;
-  } else if (spatial_.value < scale2 * kLowTexture) {
-    spatial_.level = kLow;
-  } else {
-    spatial_.level = kDefault;
-  }
-}
-
-ImageType VCMQmMethod::GetImageType(uint16_t width,
-                                    uint16_t height) {
-  // Get the image type for the encoder frame size.
-  uint32_t image_size = width * height;
-  if (image_size == kSizeOfImageType[kQCIF]) {
-    return kQCIF;
-  } else if (image_size == kSizeOfImageType[kHCIF]) {
-    return kHCIF;
-  } else if (image_size == kSizeOfImageType[kQVGA]) {
-    return kQVGA;
-  } else if (image_size == kSizeOfImageType[kCIF]) {
-    return kCIF;
-  } else if (image_size == kSizeOfImageType[kHVGA]) {
-    return kHVGA;
-  } else if (image_size == kSizeOfImageType[kVGA]) {
-    return kVGA;
-  } else if (image_size == kSizeOfImageType[kQFULLHD]) {
-    return kQFULLHD;
-  } else if (image_size == kSizeOfImageType[kWHD]) {
-    return kWHD;
-  } else if (image_size == kSizeOfImageType[kFULLHD]) {
-    return kFULLHD;
-  } else {
-    // No exact match, find closet one.
-    return FindClosestImageType(width, height);
-  }
-}
-
-ImageType VCMQmMethod::FindClosestImageType(uint16_t width, uint16_t height) {
-  float size = static_cast<float>(width * height);
-  float min = size;
-  int isel = 0;
-  for (int i = 0; i < kNumImageTypes; ++i) {
-    float dist = fabs(size - kSizeOfImageType[i]);
-    if (dist < min) {
-      min = dist;
-      isel = i;
-    }
-  }
-  return static_cast<ImageType>(isel);
-}
-
-FrameRateLevelClass VCMQmMethod::FrameRateLevel(float avg_framerate) {
-  if (avg_framerate <= kLowFrameRate) {
-    return kFrameRateLow;
-  } else if (avg_framerate <= kMiddleFrameRate) {
-    return kFrameRateMiddle1;
-  } else if (avg_framerate <= kHighFrameRate) {
-     return kFrameRateMiddle2;
-  } else {
-    return kFrameRateHigh;
-  }
-}
-
-// RESOLUTION CLASS
-
-VCMQmResolution::VCMQmResolution()
-    :  qm_(new VCMResolutionScale()) {
-  Reset();
-}
-
-VCMQmResolution::~VCMQmResolution() {
-  delete qm_;
-}
-
-void VCMQmResolution::ResetRates() {
-  sum_target_rate_ = 0.0f;
-  sum_incoming_framerate_ = 0.0f;
-  sum_rate_MM_ = 0.0f;
-  sum_rate_MM_sgn_ = 0.0f;
-  sum_packet_loss_ = 0.0f;
-  buffer_level_ = kInitBufferLevel * target_bitrate_;
-  frame_cnt_ = 0;
-  frame_cnt_delta_ = 0;
-  low_buffer_cnt_ = 0;
-  update_rate_cnt_ = 0;
-}
-
-void VCMQmResolution::ResetDownSamplingState() {
-  state_dec_factor_spatial_ = 1.0;
-  state_dec_factor_temporal_  = 1.0;
-  for (int i = 0; i < kDownActionHistorySize; i++) {
-    down_action_history_[i].spatial = kNoChangeSpatial;
-    down_action_history_[i].temporal = kNoChangeTemporal;
-  }
-}
-
-void VCMQmResolution::Reset() {
-  target_bitrate_ = 0.0f;
-  incoming_framerate_ = 0.0f;
-  buffer_level_ = 0.0f;
-  per_frame_bandwidth_ = 0.0f;
-  avg_target_rate_ = 0.0f;
-  avg_incoming_framerate_ = 0.0f;
-  avg_ratio_buffer_low_ = 0.0f;
-  avg_rate_mismatch_ = 0.0f;
-  avg_rate_mismatch_sgn_ = 0.0f;
-  avg_packet_loss_ = 0.0f;
-  encoder_state_ = kStableEncoding;
-  num_layers_ = 1;
-  ResetRates();
-  ResetDownSamplingState();
-  ResetQM();
-}
-
-EncoderState VCMQmResolution::GetEncoderState() {
-  return encoder_state_;
-}
-
-// Initialize state after re-initializing the encoder,
-// i.e., after SetEncodingData() in mediaOpt.
-int VCMQmResolution::Initialize(float bitrate,
-                                float user_framerate,
-                                uint16_t width,
-                                uint16_t height,
-                                int num_layers) {
-  if (user_framerate == 0.0f || width == 0 || height == 0) {
-    return VCM_PARAMETER_ERROR;
-  }
-  Reset();
-  target_bitrate_ = bitrate;
-  incoming_framerate_ = user_framerate;
-  UpdateCodecParameters(user_framerate, width, height);
-  native_width_ = width;
-  native_height_ = height;
-  native_frame_rate_ = user_framerate;
-  num_layers_ = num_layers;
-  // Initial buffer level.
-  buffer_level_ = kInitBufferLevel * target_bitrate_;
-  // Per-frame bandwidth.
-  per_frame_bandwidth_ = target_bitrate_ / user_framerate;
-  init_  = true;
-  return VCM_OK;
-}
-
-void VCMQmResolution::UpdateCodecParameters(float frame_rate, uint16_t width,
-                                            uint16_t height) {
-  width_ = width;
-  height_ = height;
-  // |user_frame_rate| is the target frame rate for VPM frame dropper.
-  user_frame_rate_ = frame_rate;
-  image_type_ = GetImageType(width, height);
-}
-
-// Update rate data after every encoded frame.
-void VCMQmResolution::UpdateEncodedSize(size_t encoded_size) {
-  frame_cnt_++;
-  // Convert to Kbps.
-  float encoded_size_kbits = 8.0f * static_cast<float>(encoded_size) / 1000.0f;
-
-  // Update the buffer level:
-  // Note this is not the actual encoder buffer level.
-  // |buffer_level_| is reset to an initial value after SelectResolution is
-  // called, and does not account for frame dropping by encoder or VCM.
-  buffer_level_ += per_frame_bandwidth_ - encoded_size_kbits;
-
-  // Counter for occurrences of low buffer level:
-  // low/negative values means encoder is likely dropping frames.
-  if (buffer_level_ <= kPercBufferThr * kInitBufferLevel * target_bitrate_) {
-    low_buffer_cnt_++;
-  }
-}
-
-// Update various quantities after SetTargetRates in MediaOpt.
-void VCMQmResolution::UpdateRates(float target_bitrate,
-                                  float encoder_sent_rate,
-                                  float incoming_framerate,
-                                  uint8_t packet_loss) {
-  // Sum the target bitrate: this is the encoder rate from previous update
-  // (~1sec), i.e, before the update for next ~1sec.
-  sum_target_rate_ += target_bitrate_;
-  update_rate_cnt_++;
-
-  // Sum the received (from RTCP reports) packet loss rates.
-  sum_packet_loss_ += static_cast<float>(packet_loss / 255.0);
-
-  // Sum the sequence rate mismatch:
-  // Mismatch here is based on the difference between the target rate
-  // used (in previous ~1sec) and the average actual encoding rate measured
-  // at previous ~1sec.
-  float diff = target_bitrate_ - encoder_sent_rate;
-  if (target_bitrate_ > 0.0)
-    sum_rate_MM_ += fabs(diff) / target_bitrate_;
-  int sgnDiff = diff > 0 ? 1 : (diff < 0 ? -1 : 0);
-  // To check for consistent under(+)/over_shooting(-) of target rate.
-  sum_rate_MM_sgn_ += sgnDiff;
-
-  // Update with the current new target and frame rate:
-  // these values are ones the encoder will use for the current/next ~1sec.
-  target_bitrate_ =  target_bitrate;
-  incoming_framerate_ = incoming_framerate;
-  sum_incoming_framerate_ += incoming_framerate_;
-  // Update the per_frame_bandwidth:
-  // this is the per_frame_bw for the current/next ~1sec.
-  per_frame_bandwidth_  = 0.0f;
-  if (incoming_framerate_ > 0.0f) {
-    per_frame_bandwidth_ = target_bitrate_ / incoming_framerate_;
-  }
-}
-
-// Select the resolution factors: frame size and frame rate change (qm scales).
-// Selection is for going down in resolution, or for going back up
-// (if a previous down-sampling action was taken).
-
-// In the current version the following constraints are imposed:
-// 1) We only allow for one action, either down or up, at a given time.
-// 2) The possible down-sampling actions are: spatial by 1/2x1/2, 3/4x3/4;
-//    temporal/frame rate reduction by 1/2 and 2/3.
-// 3) The action for going back up is the reverse of last (spatial or temporal)
-//    down-sampling action. The list of down-sampling actions from the
-//    Initialize() state are kept in |down_action_history_|.
-// 4) The total amount of down-sampling (spatial and/or temporal) from the
-//    Initialize() state (native resolution) is limited by various factors.
-int VCMQmResolution::SelectResolution(VCMResolutionScale** qm) {
-  if (!init_) {
-    return VCM_UNINITIALIZED;
-  }
-  if (content_metrics_ == NULL) {
-    Reset();
-    *qm =  qm_;
-    return VCM_OK;
-  }
-
-  // Check conditions on down-sampling state.
-  assert(state_dec_factor_spatial_ >= 1.0f);
-  assert(state_dec_factor_temporal_ >= 1.0f);
-  assert(state_dec_factor_spatial_ <= kMaxSpatialDown);
-  assert(state_dec_factor_temporal_ <= kMaxTempDown);
-  assert(state_dec_factor_temporal_ * state_dec_factor_spatial_ <=
-         kMaxTotalDown);
-
-  // Compute content class for selection.
-  content_class_ = ComputeContentClass();
-  // Compute various rate quantities for selection.
-  ComputeRatesForSelection();
-
-  // Get the encoder state.
-  ComputeEncoderState();
-
-  // Default settings: no action.
-  SetDefaultAction();
-  *qm = qm_;
-
-  // Check for going back up in resolution, if we have had some down-sampling
-  // relative to native state in Initialize().
-  if (down_action_history_[0].spatial != kNoChangeSpatial ||
-      down_action_history_[0].temporal != kNoChangeTemporal) {
-    if (GoingUpResolution()) {
-      *qm = qm_;
-      return VCM_OK;
-    }
-  }
-
-  // Check for going down in resolution.
-  if (GoingDownResolution()) {
-    *qm = qm_;
-    return VCM_OK;
-  }
-  return VCM_OK;
-}
-
-void VCMQmResolution::SetDefaultAction() {
-  qm_->codec_width = width_;
-  qm_->codec_height = height_;
-  qm_->frame_rate = user_frame_rate_;
-  qm_->change_resolution_spatial = false;
-  qm_->change_resolution_temporal = false;
-  qm_->spatial_width_fact = 1.0f;
-  qm_->spatial_height_fact = 1.0f;
-  qm_->temporal_fact = 1.0f;
-  action_.spatial = kNoChangeSpatial;
-  action_.temporal = kNoChangeTemporal;
-}
-
-void VCMQmResolution::ComputeRatesForSelection() {
-  avg_target_rate_ = 0.0f;
-  avg_incoming_framerate_ = 0.0f;
-  avg_ratio_buffer_low_ = 0.0f;
-  avg_rate_mismatch_ = 0.0f;
-  avg_rate_mismatch_sgn_ = 0.0f;
-  avg_packet_loss_ = 0.0f;
-  if (frame_cnt_ > 0) {
-    avg_ratio_buffer_low_ = static_cast<float>(low_buffer_cnt_) /
-        static_cast<float>(frame_cnt_);
-  }
-  if (update_rate_cnt_ > 0) {
-    avg_rate_mismatch_ = static_cast<float>(sum_rate_MM_) /
-        static_cast<float>(update_rate_cnt_);
-    avg_rate_mismatch_sgn_ = static_cast<float>(sum_rate_MM_sgn_) /
-        static_cast<float>(update_rate_cnt_);
-    avg_target_rate_ = static_cast<float>(sum_target_rate_) /
-        static_cast<float>(update_rate_cnt_);
-    avg_incoming_framerate_ = static_cast<float>(sum_incoming_framerate_) /
-        static_cast<float>(update_rate_cnt_);
-    avg_packet_loss_ =  static_cast<float>(sum_packet_loss_) /
-        static_cast<float>(update_rate_cnt_);
-  }
-  // For selection we may want to weight some quantities more heavily
-  // with the current (i.e., next ~1sec) rate values.
-  avg_target_rate_ = kWeightRate * avg_target_rate_ +
-      (1.0 - kWeightRate) * target_bitrate_;
-  avg_incoming_framerate_ = kWeightRate * avg_incoming_framerate_ +
-      (1.0 - kWeightRate) * incoming_framerate_;
-  // Use base layer frame rate for temporal layers: this will favor spatial.
-  assert(num_layers_ > 0);
-  framerate_level_ = FrameRateLevel(
-      avg_incoming_framerate_ / static_cast<float>(1 << (num_layers_ - 1)));
-}
-
-void VCMQmResolution::ComputeEncoderState() {
-  // Default.
-  encoder_state_ = kStableEncoding;
-
-  // Assign stressed state if:
-  // 1) occurrences of low buffer levels is high, or
-  // 2) rate mis-match is high, and consistent over-shooting by encoder.
-  if ((avg_ratio_buffer_low_ > kMaxBufferLow) ||
-      ((avg_rate_mismatch_ > kMaxRateMisMatch) &&
-          (avg_rate_mismatch_sgn_ < -kRateOverShoot))) {
-    encoder_state_ = kStressedEncoding;
-  }
-  // Assign easy state if:
-  // 1) rate mis-match is high, and
-  // 2) consistent under-shooting by encoder.
-  if ((avg_rate_mismatch_ > kMaxRateMisMatch) &&
-      (avg_rate_mismatch_sgn_ > kRateUnderShoot)) {
-    encoder_state_ = kEasyEncoding;
-  }
-}
-
-bool VCMQmResolution::GoingUpResolution() {
-  // For going up, we check for undoing the previous down-sampling action.
-
-  float fac_width = kFactorWidthSpatial[down_action_history_[0].spatial];
-  float fac_height = kFactorHeightSpatial[down_action_history_[0].spatial];
-  float fac_temp = kFactorTemporal[down_action_history_[0].temporal];
-  // For going up spatially, we allow for going up by 3/4x3/4 at each stage.
-  // So if the last spatial action was 1/2x1/2 it would be undone in 2 stages.
-  // Modify the fac_width/height for this case.
-  if (down_action_history_[0].spatial == kOneQuarterSpatialUniform) {
-    fac_width = kFactorWidthSpatial[kOneQuarterSpatialUniform] /
-        kFactorWidthSpatial[kOneHalfSpatialUniform];
-    fac_height = kFactorHeightSpatial[kOneQuarterSpatialUniform] /
-        kFactorHeightSpatial[kOneHalfSpatialUniform];
-  }
-
-  // Check if we should go up both spatially and temporally.
-  if (down_action_history_[0].spatial != kNoChangeSpatial &&
-      down_action_history_[0].temporal != kNoChangeTemporal) {
-    if (ConditionForGoingUp(fac_width, fac_height, fac_temp,
-                            kTransRateScaleUpSpatialTemp)) {
-      action_.spatial = down_action_history_[0].spatial;
-      action_.temporal = down_action_history_[0].temporal;
-      UpdateDownsamplingState(kUpResolution);
-      return true;
-    }
-  }
-  // Check if we should go up either spatially or temporally.
-  bool selected_up_spatial = false;
-  bool selected_up_temporal = false;
-  if (down_action_history_[0].spatial != kNoChangeSpatial) {
-    selected_up_spatial = ConditionForGoingUp(fac_width, fac_height, 1.0f,
-                                              kTransRateScaleUpSpatial);
-  }
-  if (down_action_history_[0].temporal != kNoChangeTemporal) {
-    selected_up_temporal = ConditionForGoingUp(1.0f, 1.0f, fac_temp,
-                                               kTransRateScaleUpTemp);
-  }
-  if (selected_up_spatial && !selected_up_temporal) {
-    action_.spatial = down_action_history_[0].spatial;
-    action_.temporal = kNoChangeTemporal;
-    UpdateDownsamplingState(kUpResolution);
-    return true;
-  } else if (!selected_up_spatial && selected_up_temporal) {
-    action_.spatial = kNoChangeSpatial;
-    action_.temporal = down_action_history_[0].temporal;
-    UpdateDownsamplingState(kUpResolution);
-    return true;
-  } else if (selected_up_spatial && selected_up_temporal) {
-    PickSpatialOrTemporal();
-    UpdateDownsamplingState(kUpResolution);
-    return true;
-  }
-  return false;
-}
-
-bool VCMQmResolution::ConditionForGoingUp(float fac_width,
-                                          float fac_height,
-                                          float fac_temp,
-                                          float scale_fac) {
-  float estimated_transition_rate_up = GetTransitionRate(fac_width, fac_height,
-                                                         fac_temp, scale_fac);
-  // Go back up if:
-  // 1) target rate is above threshold and current encoder state is stable, or
-  // 2) encoder state is easy (encoder is significantly under-shooting target).
-  if (((avg_target_rate_ > estimated_transition_rate_up) &&
-      (encoder_state_ == kStableEncoding)) ||
-      (encoder_state_ == kEasyEncoding)) {
-    return true;
-  } else {
-    return false;
-  }
-}
-
-bool VCMQmResolution::GoingDownResolution() {
-  float estimated_transition_rate_down =
-      GetTransitionRate(1.0f, 1.0f, 1.0f, 1.0f);
-  float max_rate = kFrameRateFac[framerate_level_] * kMaxRateQm[image_type_];
-  // Resolution reduction if:
-  // (1) target rate is below transition rate, or
-  // (2) encoder is in stressed state and target rate below a max threshold.
-  if ((avg_target_rate_ < estimated_transition_rate_down ) ||
-      (encoder_state_ == kStressedEncoding && avg_target_rate_ < max_rate)) {
-    // Get the down-sampling action: based on content class, and how low
-    // average target rate is relative to transition rate.
-    uint8_t spatial_fact =
-        kSpatialAction[content_class_ +
-                       9 * RateClass(estimated_transition_rate_down)];
-    uint8_t temp_fact =
-        kTemporalAction[content_class_ +
-                        9 * RateClass(estimated_transition_rate_down)];
-
-    switch (spatial_fact) {
-      case 4: {
-        action_.spatial = kOneQuarterSpatialUniform;
-        break;
-      }
-      case 2: {
-        action_.spatial = kOneHalfSpatialUniform;
-        break;
-      }
-      case 1: {
-        action_.spatial = kNoChangeSpatial;
-        break;
-      }
-      default: {
-        assert(false);
-      }
-    }
-    switch (temp_fact) {
-      case 3: {
-        action_.temporal = kTwoThirdsTemporal;
-        break;
-      }
-      case 2: {
-        action_.temporal = kOneHalfTemporal;
-        break;
-      }
-      case 1: {
-        action_.temporal = kNoChangeTemporal;
-        break;
-      }
-      default: {
-        assert(false);
-      }
-    }
-    // Only allow for one action (spatial or temporal) at a given time.
-    assert(action_.temporal == kNoChangeTemporal ||
-           action_.spatial == kNoChangeSpatial);
-
-    // Adjust cases not captured in tables, mainly based on frame rate, and
-    // also check for odd frame sizes.
-    AdjustAction();
-
-    // Update down-sampling state.
-    if (action_.spatial != kNoChangeSpatial ||
-        action_.temporal != kNoChangeTemporal) {
-      UpdateDownsamplingState(kDownResolution);
-      return true;
-    }
-  }
-  return false;
-}
-
-float VCMQmResolution::GetTransitionRate(float fac_width,
-                                         float fac_height,
-                                         float fac_temp,
-                                         float scale_fac) {
-  ImageType image_type = GetImageType(
-      static_cast<uint16_t>(fac_width * width_),
-      static_cast<uint16_t>(fac_height * height_));
-
-  FrameRateLevelClass framerate_level =
-      FrameRateLevel(fac_temp * avg_incoming_framerate_);
-  // If we are checking for going up temporally, and this is the last
-  // temporal action, then use native frame rate.
-  if (down_action_history_[1].temporal == kNoChangeTemporal &&
-      fac_temp > 1.0f) {
-    framerate_level = FrameRateLevel(native_frame_rate_);
-  }
-
-  // The maximum allowed rate below which down-sampling is allowed:
-  // Nominal values based on image format (frame size and frame rate).
-  float max_rate = kFrameRateFac[framerate_level] * kMaxRateQm[image_type];
-
-  uint8_t image_class = image_type > kVGA ? 1: 0;
-  uint8_t table_index = image_class * 9 + content_class_;
-  // Scale factor for down-sampling transition threshold:
-  // factor based on the content class and the image size.
-  float scaleTransRate = kScaleTransRateQm[table_index];
-  // Threshold bitrate for resolution action.
-  return static_cast<float> (scale_fac * scaleTransRate * max_rate);
-}
-
-void VCMQmResolution::UpdateDownsamplingState(UpDownAction up_down) {
-  if (up_down == kUpResolution) {
-    qm_->spatial_width_fact = 1.0f / kFactorWidthSpatial[action_.spatial];
-    qm_->spatial_height_fact = 1.0f / kFactorHeightSpatial[action_.spatial];
-    // If last spatial action was 1/2x1/2, we undo it in two steps, so the
-    // spatial scale factor in this first step is modified as (4.0/3.0 / 2.0).
-    if (action_.spatial == kOneQuarterSpatialUniform) {
-      qm_->spatial_width_fact =
-          1.0f * kFactorWidthSpatial[kOneHalfSpatialUniform] /
-          kFactorWidthSpatial[kOneQuarterSpatialUniform];
-      qm_->spatial_height_fact =
-          1.0f * kFactorHeightSpatial[kOneHalfSpatialUniform] /
-          kFactorHeightSpatial[kOneQuarterSpatialUniform];
-    }
-    qm_->temporal_fact = 1.0f / kFactorTemporal[action_.temporal];
-    RemoveLastDownAction();
-  } else if (up_down == kDownResolution) {
-    ConstrainAmountOfDownSampling();
-    ConvertSpatialFractionalToWhole();
-    qm_->spatial_width_fact = kFactorWidthSpatial[action_.spatial];
-    qm_->spatial_height_fact = kFactorHeightSpatial[action_.spatial];
-    qm_->temporal_fact = kFactorTemporal[action_.temporal];
-    InsertLatestDownAction();
-  } else {
-    // This function should only be called if either the Up or Down action
-    // has been selected.
-    assert(false);
-  }
-  UpdateCodecResolution();
-  state_dec_factor_spatial_ = state_dec_factor_spatial_ *
-      qm_->spatial_width_fact * qm_->spatial_height_fact;
-  state_dec_factor_temporal_ = state_dec_factor_temporal_ * qm_->temporal_fact;
-}
-
-void  VCMQmResolution::UpdateCodecResolution() {
-  if (action_.spatial != kNoChangeSpatial) {
-    qm_->change_resolution_spatial = true;
-    qm_->codec_width = static_cast<uint16_t>(width_ /
-                                             qm_->spatial_width_fact + 0.5f);
-    qm_->codec_height = static_cast<uint16_t>(height_ /
-                                              qm_->spatial_height_fact + 0.5f);
-    // Size should not exceed native sizes.
-    assert(qm_->codec_width <= native_width_);
-    assert(qm_->codec_height <= native_height_);
-    // New sizes should be multiple of 2, otherwise spatial should not have
-    // been selected.
-    assert(qm_->codec_width % 2 == 0);
-    assert(qm_->codec_height % 2 == 0);
-  }
-  if (action_.temporal != kNoChangeTemporal) {
-    qm_->change_resolution_temporal = true;
-    // Update the frame rate based on the average incoming frame rate.
-    qm_->frame_rate = avg_incoming_framerate_ / qm_->temporal_fact + 0.5f;
-    if (down_action_history_[0].temporal == 0) {
-      // When we undo the last temporal-down action, make sure we go back up
-      // to the native frame rate. Since the incoming frame rate may
-      // fluctuate over time, |avg_incoming_framerate_| scaled back up may
-      // be smaller than |native_frame rate_|.
-      qm_->frame_rate = native_frame_rate_;
-    }
-  }
-}
-
-uint8_t VCMQmResolution::RateClass(float transition_rate) {
-  return avg_target_rate_ < (kFacLowRate * transition_rate) ? 0:
-  (avg_target_rate_ >= transition_rate ? 2 : 1);
-}
-
-// TODO(marpan): Would be better to capture these frame rate adjustments by
-// extending the table data (qm_select_data.h).
-void VCMQmResolution::AdjustAction() {
-  // If the spatial level is default state (neither low or high), motion level
-  // is not high, and spatial action was selected, switch to 2/3 frame rate
-  // reduction if the average incoming frame rate is high.
-  if (spatial_.level == kDefault && motion_.level != kHigh &&
-      action_.spatial != kNoChangeSpatial &&
-      framerate_level_ == kFrameRateHigh) {
-    action_.spatial = kNoChangeSpatial;
-    action_.temporal = kTwoThirdsTemporal;
-  }
-  // If both motion and spatial level are low, and temporal down action was
-  // selected, switch to spatial 3/4x3/4 if the frame rate is not above the
-  // lower middle level (|kFrameRateMiddle1|).
-  if (motion_.level == kLow && spatial_.level == kLow &&
-      framerate_level_ <= kFrameRateMiddle1 &&
-      action_.temporal != kNoChangeTemporal) {
-    action_.spatial = kOneHalfSpatialUniform;
-    action_.temporal = kNoChangeTemporal;
-  }
-  // If spatial action is selected, and there has been too much spatial
-  // reduction already (i.e., 1/4), then switch to temporal action if the
-  // average frame rate is not low.
-  if (action_.spatial != kNoChangeSpatial &&
-      down_action_history_[0].spatial == kOneQuarterSpatialUniform &&
-      framerate_level_ != kFrameRateLow) {
-    action_.spatial = kNoChangeSpatial;
-    action_.temporal = kTwoThirdsTemporal;
-  }
-  // Never use temporal action if number of temporal layers is above 2.
-  if (num_layers_ > 2) {
-    if (action_.temporal !=  kNoChangeTemporal) {
-      action_.spatial = kOneHalfSpatialUniform;
-    }
-    action_.temporal = kNoChangeTemporal;
-  }
-  // If spatial action was selected, we need to make sure the frame sizes
-  // are multiples of two. Otherwise switch to 2/3 temporal.
-  if (action_.spatial != kNoChangeSpatial &&
-      !EvenFrameSize()) {
-    action_.spatial = kNoChangeSpatial;
-    // Only one action (spatial or temporal) is allowed at a given time, so need
-    // to check whether temporal action is currently selected.
-    action_.temporal = kTwoThirdsTemporal;
-  }
-}
-
-void VCMQmResolution::ConvertSpatialFractionalToWhole() {
-  // If 3/4 spatial is selected, check if there has been another 3/4,
-  // and if so, combine them into 1/2. 1/2 scaling is more efficient than 9/16.
-  // Note we define 3/4x3/4 spatial as kOneHalfSpatialUniform.
-  if (action_.spatial == kOneHalfSpatialUniform) {
-    bool found = false;
-    int isel = kDownActionHistorySize;
-    for (int i = 0; i < kDownActionHistorySize; ++i) {
-      if (down_action_history_[i].spatial ==  kOneHalfSpatialUniform) {
-        isel = i;
-        found = true;
-        break;
-      }
-    }
-    if (found) {
-       action_.spatial = kOneQuarterSpatialUniform;
-       state_dec_factor_spatial_ = state_dec_factor_spatial_ /
-           (kFactorWidthSpatial[kOneHalfSpatialUniform] *
-            kFactorHeightSpatial[kOneHalfSpatialUniform]);
-       // Check if switching to 1/2x1/2 (=1/4) spatial is allowed.
-       ConstrainAmountOfDownSampling();
-       if (action_.spatial == kNoChangeSpatial) {
-         // Not allowed. Go back to 3/4x3/4 spatial.
-         action_.spatial = kOneHalfSpatialUniform;
-         state_dec_factor_spatial_ = state_dec_factor_spatial_ *
-             kFactorWidthSpatial[kOneHalfSpatialUniform] *
-             kFactorHeightSpatial[kOneHalfSpatialUniform];
-       } else {
-         // Switching is allowed. Remove 3/4x3/4 from the history, and update
-         // the frame size.
-         for (int i = isel; i < kDownActionHistorySize - 1; ++i) {
-           down_action_history_[i].spatial =
-               down_action_history_[i + 1].spatial;
-         }
-         width_ = width_ * kFactorWidthSpatial[kOneHalfSpatialUniform];
-         height_ = height_ * kFactorHeightSpatial[kOneHalfSpatialUniform];
-       }
-    }
-  }
-}
-
-// Returns false if the new frame sizes, under the current spatial action,
-// are not multiples of two.
-bool VCMQmResolution::EvenFrameSize() {
-  if (action_.spatial == kOneHalfSpatialUniform) {
-    if ((width_ * 3 / 4) % 2 != 0 || (height_ * 3 / 4) % 2 != 0) {
-      return false;
-    }
-  } else if (action_.spatial == kOneQuarterSpatialUniform) {
-    if ((width_ * 1 / 2) % 2 != 0 || (height_ * 1 / 2) % 2 != 0) {
-      return false;
-    }
-  }
-  return true;
-}
-
-void VCMQmResolution::InsertLatestDownAction() {
-  if (action_.spatial != kNoChangeSpatial) {
-    for (int i = kDownActionHistorySize - 1; i > 0; --i) {
-      down_action_history_[i].spatial = down_action_history_[i - 1].spatial;
-    }
-    down_action_history_[0].spatial = action_.spatial;
-  }
-  if (action_.temporal != kNoChangeTemporal) {
-    for (int i = kDownActionHistorySize - 1; i > 0; --i) {
-      down_action_history_[i].temporal = down_action_history_[i - 1].temporal;
-    }
-    down_action_history_[0].temporal = action_.temporal;
-  }
-}
-
-void VCMQmResolution::RemoveLastDownAction() {
-  if (action_.spatial != kNoChangeSpatial) {
-    // If the last spatial action was 1/2x1/2 we replace it with 3/4x3/4.
-    if (action_.spatial == kOneQuarterSpatialUniform) {
-      down_action_history_[0].spatial = kOneHalfSpatialUniform;
-    } else {
-      for (int i = 0; i < kDownActionHistorySize - 1; ++i) {
-        down_action_history_[i].spatial = down_action_history_[i + 1].spatial;
-      }
-      down_action_history_[kDownActionHistorySize - 1].spatial =
-          kNoChangeSpatial;
-    }
-  }
-  if (action_.temporal != kNoChangeTemporal) {
-    for (int i = 0; i < kDownActionHistorySize - 1; ++i) {
-      down_action_history_[i].temporal = down_action_history_[i + 1].temporal;
-    }
-    down_action_history_[kDownActionHistorySize - 1].temporal =
-        kNoChangeTemporal;
-  }
-}
-
-void VCMQmResolution::ConstrainAmountOfDownSampling() {
-  // Sanity checks on down-sampling selection:
-  // override the settings for too small image size and/or frame rate.
-  // Also check the limit on current down-sampling states.
-
-  float spatial_width_fact = kFactorWidthSpatial[action_.spatial];
-  float spatial_height_fact = kFactorHeightSpatial[action_.spatial];
-  float temporal_fact = kFactorTemporal[action_.temporal];
-  float new_dec_factor_spatial = state_dec_factor_spatial_ *
-      spatial_width_fact * spatial_height_fact;
-  float new_dec_factor_temp = state_dec_factor_temporal_ * temporal_fact;
-
-  // No spatial sampling if current frame size is too small, or if the
-  // amount of spatial down-sampling is above maximum spatial down-action.
-  if ((width_ * height_) <= kMinImageSize ||
-      new_dec_factor_spatial > kMaxSpatialDown) {
-    action_.spatial = kNoChangeSpatial;
-    new_dec_factor_spatial = state_dec_factor_spatial_;
-  }
-  // No frame rate reduction if average frame rate is below some point, or if
-  // the amount of temporal down-sampling is above maximum temporal down-action.
-  if (avg_incoming_framerate_ <= kMinFrameRate ||
-      new_dec_factor_temp > kMaxTempDown) {
-    action_.temporal = kNoChangeTemporal;
-    new_dec_factor_temp = state_dec_factor_temporal_;
-  }
-  // Check if the total (spatial-temporal) down-action is above maximum allowed,
-  // if so, disallow the current selected down-action.
-  if (new_dec_factor_spatial * new_dec_factor_temp > kMaxTotalDown) {
-    if (action_.spatial != kNoChangeSpatial) {
-      action_.spatial = kNoChangeSpatial;
-    } else if (action_.temporal != kNoChangeTemporal) {
-      action_.temporal = kNoChangeTemporal;
-    } else {
-      // We only allow for one action (spatial or temporal) at a given time, so
-      // either spatial or temporal action is selected when this function is
-      // called. If the selected action is disallowed from one of the above
-      // 2 prior conditions (on spatial & temporal max down-action), then this
-      // condition "total down-action > |kMaxTotalDown|" would not be entered.
-      assert(false);
-    }
-  }
-}
-
-void VCMQmResolution::PickSpatialOrTemporal() {
-  // Pick the one that has had the most down-sampling thus far.
-  if (state_dec_factor_spatial_ > state_dec_factor_temporal_) {
-    action_.spatial = down_action_history_[0].spatial;
-    action_.temporal = kNoChangeTemporal;
-  } else {
-    action_.spatial = kNoChangeSpatial;
-    action_.temporal = down_action_history_[0].temporal;
-  }
-}
-
-// TODO(marpan): Update when we allow for directional spatial down-sampling.
-void VCMQmResolution::SelectSpatialDirectionMode(float transition_rate) {
-  // Default is 4/3x4/3
-  // For bit rates well below transitional rate, we select 2x2.
-  if (avg_target_rate_ < transition_rate * kRateRedSpatial2X2) {
-    qm_->spatial_width_fact = 2.0f;
-    qm_->spatial_height_fact = 2.0f;
-  }
-  // Otherwise check prediction errors and aspect ratio.
-  float spatial_err = 0.0f;
-  float spatial_err_h = 0.0f;
-  float spatial_err_v = 0.0f;
-  if (content_metrics_) {
-    spatial_err = content_metrics_->spatial_pred_err;
-    spatial_err_h = content_metrics_->spatial_pred_err_h;
-    spatial_err_v = content_metrics_->spatial_pred_err_v;
-  }
-
-  // Favor 1x2 if aspect_ratio is 16:9.
-  if (aspect_ratio_ >= 16.0f / 9.0f) {
-    // Check if 1x2 has lowest prediction error.
-    if (spatial_err_h < spatial_err && spatial_err_h < spatial_err_v) {
-      qm_->spatial_width_fact = 2.0f;
-      qm_->spatial_height_fact = 1.0f;
-    }
-  }
-  // Check for 4/3x4/3 selection: favor 2x2 over 1x2 and 2x1.
-  if (spatial_err < spatial_err_h * (1.0f + kSpatialErr2x2VsHoriz) &&
-      spatial_err < spatial_err_v * (1.0f + kSpatialErr2X2VsVert)) {
-    qm_->spatial_width_fact = 4.0f / 3.0f;
-    qm_->spatial_height_fact = 4.0f / 3.0f;
-  }
-  // Check for 2x1 selection.
-  if (spatial_err_v < spatial_err_h * (1.0f - kSpatialErrVertVsHoriz) &&
-      spatial_err_v < spatial_err * (1.0f - kSpatialErr2X2VsVert)) {
-    qm_->spatial_width_fact = 1.0f;
-    qm_->spatial_height_fact = 2.0f;
-  }
-}
-
-// ROBUSTNESS CLASS
-
-VCMQmRobustness::VCMQmRobustness() {
-  Reset();
-}
-
-VCMQmRobustness::~VCMQmRobustness() {
-}
-
-void VCMQmRobustness::Reset() {
-  prev_total_rate_ = 0.0f;
-  prev_rtt_time_ = 0;
-  prev_packet_loss_ = 0;
-  prev_code_rate_delta_ = 0;
-  ResetQM();
-}
-
-// Adjust the FEC rate based on the content and the network state
-// (packet loss rate, total rate/bandwidth, round trip time).
-// Note that packetLoss here is the filtered loss value.
-float VCMQmRobustness::AdjustFecFactor(uint8_t code_rate_delta,
-                                       float total_rate,
-                                       float framerate,
-                                       int64_t rtt_time,
-                                       uint8_t packet_loss) {
-  // Default: no adjustment
-  float adjust_fec =  1.0f;
-  if (content_metrics_ == NULL) {
-    return adjust_fec;
-  }
-  // Compute class state of the content.
-  ComputeMotionNFD();
-  ComputeSpatial();
-
-  // TODO(marpan): Set FEC adjustment factor.
-
-  // Keep track of previous values of network state:
-  // adjustment may be also based on pattern of changes in network state.
-  prev_total_rate_ = total_rate;
-  prev_rtt_time_ = rtt_time;
-  prev_packet_loss_ = packet_loss;
-  prev_code_rate_delta_ = code_rate_delta;
-  return adjust_fec;
-}
-
-// Set the UEP (unequal-protection across packets) on/off for the FEC.
-bool VCMQmRobustness::SetUepProtection(uint8_t code_rate_delta,
-                                       float total_rate,
-                                       uint8_t packet_loss,
-                                       bool frame_type) {
-  // Default.
-  return false;
-}
-}  // namespace