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/*
* Copyright 2020 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 "call/adaptation/video_stream_adapter.h"
#include <algorithm>
#include <limits>
#include <utility>
#include "absl/types/optional.h"
#include "absl/types/variant.h"
#include "api/sequence_checker.h"
#include "api/video/video_adaptation_counters.h"
#include "api/video/video_adaptation_reason.h"
#include "api/video_codecs/video_encoder.h"
#include "call/adaptation/video_source_restrictions.h"
#include "call/adaptation/video_stream_input_state.h"
#include "rtc_base/checks.h"
#include "rtc_base/constructor_magic.h"
#include "rtc_base/logging.h"
#include "rtc_base/numerics/safe_conversions.h"
namespace webrtc {
const int kMinFrameRateFps = 2;
namespace {
// For frame rate, the steps we take are 2/3 (down) and 3/2 (up).
int GetLowerFrameRateThan(int fps) {
RTC_DCHECK(fps != std::numeric_limits<int>::max());
return (fps * 2) / 3;
}
// TODO(hbos): Use absl::optional<> instead?
int GetHigherFrameRateThan(int fps) {
return fps != std::numeric_limits<int>::max()
? (fps * 3) / 2
: std::numeric_limits<int>::max();
}
int GetIncreasedMaxPixelsWanted(int target_pixels) {
if (target_pixels == std::numeric_limits<int>::max())
return std::numeric_limits<int>::max();
// When we decrease resolution, we go down to at most 3/5 of current pixels.
// Thus to increase resolution, we need 3/5 to get back to where we started.
// When going up, the desired max_pixels_per_frame() has to be significantly
// higher than the target because the source's native resolutions might not
// match the target. We pick 12/5 of the target.
//
// (This value was historically 4 times the old target, which is (3/5)*4 of
// the new target - or 12/5 - assuming the target is adjusted according to
// the above steps.)
RTC_DCHECK(target_pixels != std::numeric_limits<int>::max());
return (target_pixels * 12) / 5;
}
bool CanDecreaseResolutionTo(int target_pixels,
int target_pixels_min,
const VideoStreamInputState& input_state,
const VideoSourceRestrictions& restrictions) {
int max_pixels_per_frame =
rtc::dchecked_cast<int>(restrictions.max_pixels_per_frame().value_or(
std::numeric_limits<int>::max()));
return target_pixels < max_pixels_per_frame &&
target_pixels_min >= input_state.min_pixels_per_frame();
}
bool CanIncreaseResolutionTo(int target_pixels,
const VideoSourceRestrictions& restrictions) {
int max_pixels_wanted = GetIncreasedMaxPixelsWanted(target_pixels);
int max_pixels_per_frame =
rtc::dchecked_cast<int>(restrictions.max_pixels_per_frame().value_or(
std::numeric_limits<int>::max()));
return max_pixels_wanted > max_pixels_per_frame;
}
bool CanDecreaseFrameRateTo(int max_frame_rate,
const VideoSourceRestrictions& restrictions) {
const int fps_wanted = std::max(kMinFrameRateFps, max_frame_rate);
return fps_wanted <
rtc::dchecked_cast<int>(restrictions.max_frame_rate().value_or(
std::numeric_limits<int>::max()));
}
bool CanIncreaseFrameRateTo(int max_frame_rate,
const VideoSourceRestrictions& restrictions) {
return max_frame_rate >
rtc::dchecked_cast<int>(restrictions.max_frame_rate().value_or(
std::numeric_limits<int>::max()));
}
bool MinPixelLimitReached(const VideoStreamInputState& input_state) {
if (input_state.single_active_stream_pixels().has_value()) {
return GetLowerResolutionThan(
input_state.single_active_stream_pixels().value()) <
input_state.min_pixels_per_frame();
}
return input_state.frame_size_pixels().has_value() &&
GetLowerResolutionThan(input_state.frame_size_pixels().value()) <
input_state.min_pixels_per_frame();
}
} // namespace
VideoSourceRestrictionsListener::~VideoSourceRestrictionsListener() = default;
VideoSourceRestrictions FilterRestrictionsByDegradationPreference(
VideoSourceRestrictions source_restrictions,
DegradationPreference degradation_preference) {
switch (degradation_preference) {
case DegradationPreference::BALANCED:
break;
case DegradationPreference::MAINTAIN_FRAMERATE:
source_restrictions.set_max_frame_rate(absl::nullopt);
break;
case DegradationPreference::MAINTAIN_RESOLUTION:
source_restrictions.set_max_pixels_per_frame(absl::nullopt);
source_restrictions.set_target_pixels_per_frame(absl::nullopt);
break;
case DegradationPreference::DISABLED:
source_restrictions.set_max_pixels_per_frame(absl::nullopt);
source_restrictions.set_target_pixels_per_frame(absl::nullopt);
source_restrictions.set_max_frame_rate(absl::nullopt);
}
return source_restrictions;
}
// For resolution, the steps we take are 3/5 (down) and 5/3 (up).
// Notice the asymmetry of which restriction property is set depending on if
// we are adapting up or down:
// - VideoSourceRestrictor::DecreaseResolution() sets the max_pixels_per_frame()
// to the desired target and target_pixels_per_frame() to null.
// - VideoSourceRestrictor::IncreaseResolutionTo() sets the
// target_pixels_per_frame() to the desired target, and max_pixels_per_frame()
// is set according to VideoSourceRestrictor::GetIncreasedMaxPixelsWanted().
int GetLowerResolutionThan(int pixel_count) {
RTC_DCHECK(pixel_count != std::numeric_limits<int>::max());
return (pixel_count * 3) / 5;
}
// TODO(hbos): Use absl::optional<> instead?
int GetHigherResolutionThan(int pixel_count) {
return pixel_count != std::numeric_limits<int>::max()
? (pixel_count * 5) / 3
: std::numeric_limits<int>::max();
}
// static
const char* Adaptation::StatusToString(Adaptation::Status status) {
switch (status) {
case Adaptation::Status::kValid:
return "kValid";
case Adaptation::Status::kLimitReached:
return "kLimitReached";
case Adaptation::Status::kAwaitingPreviousAdaptation:
return "kAwaitingPreviousAdaptation";
case Status::kInsufficientInput:
return "kInsufficientInput";
case Status::kAdaptationDisabled:
return "kAdaptationDisabled";
case Status::kRejectedByConstraint:
return "kRejectedByConstraint";
}
RTC_CHECK_NOTREACHED();
}
Adaptation::Adaptation(int validation_id,
VideoSourceRestrictions restrictions,
VideoAdaptationCounters counters,
VideoStreamInputState input_state)
: validation_id_(validation_id),
status_(Status::kValid),
input_state_(std::move(input_state)),
restrictions_(std::move(restrictions)),
counters_(std::move(counters)) {}
Adaptation::Adaptation(int validation_id, Status invalid_status)
: validation_id_(validation_id), status_(invalid_status) {
RTC_DCHECK_NE(status_, Status::kValid);
}
Adaptation::Status Adaptation::status() const {
return status_;
}
const VideoStreamInputState& Adaptation::input_state() const {
return input_state_;
}
const VideoSourceRestrictions& Adaptation::restrictions() const {
return restrictions_;
}
const VideoAdaptationCounters& Adaptation::counters() const {
return counters_;
}
VideoStreamAdapter::VideoStreamAdapter(
VideoStreamInputStateProvider* input_state_provider,
VideoStreamEncoderObserver* encoder_stats_observer)
: input_state_provider_(input_state_provider),
encoder_stats_observer_(encoder_stats_observer),
adaptation_validation_id_(0),
degradation_preference_(DegradationPreference::DISABLED),
awaiting_frame_size_change_(absl::nullopt) {
sequence_checker_.Detach();
RTC_DCHECK(input_state_provider_);
RTC_DCHECK(encoder_stats_observer_);
}
VideoStreamAdapter::~VideoStreamAdapter() {
RTC_DCHECK(adaptation_constraints_.empty())
<< "There are constaint(s) attached to a VideoStreamAdapter being "
"destroyed.";
}
VideoSourceRestrictions VideoStreamAdapter::source_restrictions() const {
RTC_DCHECK_RUN_ON(&sequence_checker_);
return current_restrictions_.restrictions;
}
const VideoAdaptationCounters& VideoStreamAdapter::adaptation_counters() const {
RTC_DCHECK_RUN_ON(&sequence_checker_);
return current_restrictions_.counters;
}
void VideoStreamAdapter::ClearRestrictions() {
RTC_DCHECK_RUN_ON(&sequence_checker_);
// Invalidate any previously returned Adaptation.
RTC_LOG(LS_INFO) << "Resetting restrictions";
++adaptation_validation_id_;
current_restrictions_ = {VideoSourceRestrictions(),
VideoAdaptationCounters()};
awaiting_frame_size_change_ = absl::nullopt;
BroadcastVideoRestrictionsUpdate(input_state_provider_->InputState(),
nullptr);
}
void VideoStreamAdapter::AddRestrictionsListener(
VideoSourceRestrictionsListener* restrictions_listener) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
RTC_DCHECK(std::find(restrictions_listeners_.begin(),
restrictions_listeners_.end(),
restrictions_listener) == restrictions_listeners_.end());
restrictions_listeners_.push_back(restrictions_listener);
}
void VideoStreamAdapter::RemoveRestrictionsListener(
VideoSourceRestrictionsListener* restrictions_listener) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
auto it = std::find(restrictions_listeners_.begin(),
restrictions_listeners_.end(), restrictions_listener);
RTC_DCHECK(it != restrictions_listeners_.end());
restrictions_listeners_.erase(it);
}
void VideoStreamAdapter::AddAdaptationConstraint(
AdaptationConstraint* adaptation_constraint) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
RTC_DCHECK(std::find(adaptation_constraints_.begin(),
adaptation_constraints_.end(),
adaptation_constraint) == adaptation_constraints_.end());
adaptation_constraints_.push_back(adaptation_constraint);
}
void VideoStreamAdapter::RemoveAdaptationConstraint(
AdaptationConstraint* adaptation_constraint) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
auto it = std::find(adaptation_constraints_.begin(),
adaptation_constraints_.end(), adaptation_constraint);
RTC_DCHECK(it != adaptation_constraints_.end());
adaptation_constraints_.erase(it);
}
void VideoStreamAdapter::SetDegradationPreference(
DegradationPreference degradation_preference) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
if (degradation_preference_ == degradation_preference)
return;
// Invalidate any previously returned Adaptation.
++adaptation_validation_id_;
bool balanced_switch =
degradation_preference == DegradationPreference::BALANCED ||
degradation_preference_ == DegradationPreference::BALANCED;
degradation_preference_ = degradation_preference;
if (balanced_switch) {
// ClearRestrictions() calls BroadcastVideoRestrictionsUpdate(nullptr).
ClearRestrictions();
} else {
BroadcastVideoRestrictionsUpdate(input_state_provider_->InputState(),
nullptr);
}
}
struct VideoStreamAdapter::RestrictionsOrStateVisitor {
Adaptation operator()(const RestrictionsWithCounters& r) const {
return Adaptation(adaptation_validation_id, r.restrictions, r.counters,
input_state);
}
Adaptation operator()(const Adaptation::Status& status) const {
RTC_DCHECK_NE(status, Adaptation::Status::kValid);
return Adaptation(adaptation_validation_id, status);
}
const int adaptation_validation_id;
const VideoStreamInputState& input_state;
};
Adaptation VideoStreamAdapter::RestrictionsOrStateToAdaptation(
VideoStreamAdapter::RestrictionsOrState step_or_state,
const VideoStreamInputState& input_state) const {
RTC_DCHECK(!step_or_state.valueless_by_exception());
return absl::visit(
RestrictionsOrStateVisitor{adaptation_validation_id_, input_state},
step_or_state);
}
Adaptation VideoStreamAdapter::GetAdaptationUp(
const VideoStreamInputState& input_state) const {
RestrictionsOrState step = GetAdaptationUpStep(input_state);
// If an adaptation proposed, check with the constraints that it is ok.
if (absl::holds_alternative<RestrictionsWithCounters>(step)) {
RestrictionsWithCounters restrictions =
absl::get<RestrictionsWithCounters>(step);
for (const auto* constraint : adaptation_constraints_) {
if (!constraint->IsAdaptationUpAllowed(input_state,
current_restrictions_.restrictions,
restrictions.restrictions)) {
RTC_LOG(LS_INFO) << "Not adapting up because constraint \""
<< constraint->Name() << "\" disallowed it";
step = Adaptation::Status::kRejectedByConstraint;
}
}
}
return RestrictionsOrStateToAdaptation(step, input_state);
}
Adaptation VideoStreamAdapter::GetAdaptationUp() {
RTC_DCHECK_RUN_ON(&sequence_checker_);
VideoStreamInputState input_state = input_state_provider_->InputState();
++adaptation_validation_id_;
Adaptation adaptation = GetAdaptationUp(input_state);
return adaptation;
}
VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::GetAdaptationUpStep(
const VideoStreamInputState& input_state) const {
if (!HasSufficientInputForAdaptation(input_state)) {
return Adaptation::Status::kInsufficientInput;
}
// Don't adapt if we're awaiting a previous adaptation to have an effect.
if (awaiting_frame_size_change_ &&
awaiting_frame_size_change_->pixels_increased &&
degradation_preference_ == DegradationPreference::MAINTAIN_FRAMERATE &&
input_state.frame_size_pixels().value() <=
awaiting_frame_size_change_->frame_size_pixels) {
return Adaptation::Status::kAwaitingPreviousAdaptation;
}
// Maybe propose targets based on degradation preference.
switch (degradation_preference_) {
case DegradationPreference::BALANCED: {
// Attempt to increase target frame rate.
RestrictionsOrState increase_frame_rate =
IncreaseFramerate(input_state, current_restrictions_);
if (absl::holds_alternative<RestrictionsWithCounters>(
increase_frame_rate)) {
return increase_frame_rate;
}
// else, increase resolution.
[[fallthrough]];
}
case DegradationPreference::MAINTAIN_FRAMERATE: {
// Attempt to increase pixel count.
return IncreaseResolution(input_state, current_restrictions_);
}
case DegradationPreference::MAINTAIN_RESOLUTION: {
// Scale up framerate.
return IncreaseFramerate(input_state, current_restrictions_);
}
case DegradationPreference::DISABLED:
return Adaptation::Status::kAdaptationDisabled;
}
RTC_CHECK_NOTREACHED();
}
Adaptation VideoStreamAdapter::GetAdaptationDown() {
RTC_DCHECK_RUN_ON(&sequence_checker_);
VideoStreamInputState input_state = input_state_provider_->InputState();
++adaptation_validation_id_;
RestrictionsOrState restrictions_or_state =
GetAdaptationDownStep(input_state, current_restrictions_);
if (MinPixelLimitReached(input_state)) {
encoder_stats_observer_->OnMinPixelLimitReached();
}
// Check for min_fps
if (degradation_preference_ == DegradationPreference::BALANCED &&
absl::holds_alternative<RestrictionsWithCounters>(
restrictions_or_state)) {
restrictions_or_state = AdaptIfFpsDiffInsufficient(
input_state,
absl::get<RestrictionsWithCounters>(restrictions_or_state));
}
return RestrictionsOrStateToAdaptation(restrictions_or_state, input_state);
}
VideoStreamAdapter::RestrictionsOrState
VideoStreamAdapter::AdaptIfFpsDiffInsufficient(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& restrictions) const {
RTC_DCHECK_EQ(degradation_preference_, DegradationPreference::BALANCED);
int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
input_state.frame_size_pixels().value());
absl::optional<int> min_fps_diff =
balanced_settings_.MinFpsDiff(frame_size_pixels);
if (current_restrictions_.counters.fps_adaptations <
restrictions.counters.fps_adaptations &&
min_fps_diff && input_state.frames_per_second() > 0) {
int fps_diff = input_state.frames_per_second() -
restrictions.restrictions.max_frame_rate().value();
if (fps_diff < min_fps_diff.value()) {
return GetAdaptationDownStep(input_state, restrictions);
}
}
return restrictions;
}
VideoStreamAdapter::RestrictionsOrState
VideoStreamAdapter::GetAdaptationDownStep(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& current_restrictions) const {
if (!HasSufficientInputForAdaptation(input_state)) {
return Adaptation::Status::kInsufficientInput;
}
// Don't adapt if we're awaiting a previous adaptation to have an effect or
// if we switched degradation preference.
if (awaiting_frame_size_change_ &&
!awaiting_frame_size_change_->pixels_increased &&
degradation_preference_ == DegradationPreference::MAINTAIN_FRAMERATE &&
input_state.frame_size_pixels().value() >=
awaiting_frame_size_change_->frame_size_pixels) {
return Adaptation::Status::kAwaitingPreviousAdaptation;
}
// Maybe propose targets based on degradation preference.
switch (degradation_preference_) {
case DegradationPreference::BALANCED: {
// Try scale down framerate, if lower.
RestrictionsOrState decrease_frame_rate =
DecreaseFramerate(input_state, current_restrictions);
if (absl::holds_alternative<RestrictionsWithCounters>(
decrease_frame_rate)) {
return decrease_frame_rate;
}
// else, decrease resolution.
[[fallthrough]];
}
case DegradationPreference::MAINTAIN_FRAMERATE: {
return DecreaseResolution(input_state, current_restrictions);
}
case DegradationPreference::MAINTAIN_RESOLUTION: {
return DecreaseFramerate(input_state, current_restrictions);
}
case DegradationPreference::DISABLED:
return Adaptation::Status::kAdaptationDisabled;
}
RTC_CHECK_NOTREACHED();
}
VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::DecreaseResolution(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& current_restrictions) {
int target_pixels =
GetLowerResolutionThan(input_state.frame_size_pixels().value());
// Use single active stream if set, this stream could be lower than the input.
int target_pixels_min =
GetLowerResolutionThan(input_state.single_active_stream_pixels().value_or(
input_state.frame_size_pixels().value()));
if (!CanDecreaseResolutionTo(target_pixels, target_pixels_min, input_state,
current_restrictions.restrictions)) {
return Adaptation::Status::kLimitReached;
}
RestrictionsWithCounters new_restrictions = current_restrictions;
RTC_LOG(LS_INFO) << "Scaling down resolution, max pixels: " << target_pixels;
new_restrictions.restrictions.set_max_pixels_per_frame(
target_pixels != std::numeric_limits<int>::max()
? absl::optional<size_t>(target_pixels)
: absl::nullopt);
new_restrictions.restrictions.set_target_pixels_per_frame(absl::nullopt);
++new_restrictions.counters.resolution_adaptations;
return new_restrictions;
}
VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::DecreaseFramerate(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& current_restrictions) const {
int max_frame_rate;
if (degradation_preference_ == DegradationPreference::MAINTAIN_RESOLUTION) {
max_frame_rate = GetLowerFrameRateThan(input_state.frames_per_second());
} else if (degradation_preference_ == DegradationPreference::BALANCED) {
int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
input_state.frame_size_pixels().value());
max_frame_rate = balanced_settings_.MinFps(input_state.video_codec_type(),
frame_size_pixels);
} else {
RTC_DCHECK_NOTREACHED();
max_frame_rate = GetLowerFrameRateThan(input_state.frames_per_second());
}
if (!CanDecreaseFrameRateTo(max_frame_rate,
current_restrictions.restrictions)) {
return Adaptation::Status::kLimitReached;
}
RestrictionsWithCounters new_restrictions = current_restrictions;
max_frame_rate = std::max(kMinFrameRateFps, max_frame_rate);
RTC_LOG(LS_INFO) << "Scaling down framerate: " << max_frame_rate;
new_restrictions.restrictions.set_max_frame_rate(
max_frame_rate != std::numeric_limits<int>::max()
? absl::optional<double>(max_frame_rate)
: absl::nullopt);
++new_restrictions.counters.fps_adaptations;
return new_restrictions;
}
VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::IncreaseResolution(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& current_restrictions) {
int target_pixels = input_state.frame_size_pixels().value();
if (current_restrictions.counters.resolution_adaptations == 1) {
RTC_LOG(LS_INFO) << "Removing resolution down-scaling setting.";
target_pixels = std::numeric_limits<int>::max();
}
target_pixels = GetHigherResolutionThan(target_pixels);
if (!CanIncreaseResolutionTo(target_pixels,
current_restrictions.restrictions)) {
return Adaptation::Status::kLimitReached;
}
int max_pixels_wanted = GetIncreasedMaxPixelsWanted(target_pixels);
RestrictionsWithCounters new_restrictions = current_restrictions;
RTC_LOG(LS_INFO) << "Scaling up resolution, max pixels: "
<< max_pixels_wanted;
new_restrictions.restrictions.set_max_pixels_per_frame(
max_pixels_wanted != std::numeric_limits<int>::max()
? absl::optional<size_t>(max_pixels_wanted)
: absl::nullopt);
new_restrictions.restrictions.set_target_pixels_per_frame(
max_pixels_wanted != std::numeric_limits<int>::max()
? absl::optional<size_t>(target_pixels)
: absl::nullopt);
--new_restrictions.counters.resolution_adaptations;
RTC_DCHECK_GE(new_restrictions.counters.resolution_adaptations, 0);
return new_restrictions;
}
VideoStreamAdapter::RestrictionsOrState VideoStreamAdapter::IncreaseFramerate(
const VideoStreamInputState& input_state,
const RestrictionsWithCounters& current_restrictions) const {
int max_frame_rate;
if (degradation_preference_ == DegradationPreference::MAINTAIN_RESOLUTION) {
max_frame_rate = GetHigherFrameRateThan(input_state.frames_per_second());
} else if (degradation_preference_ == DegradationPreference::BALANCED) {
int frame_size_pixels = input_state.single_active_stream_pixels().value_or(
input_state.frame_size_pixels().value());
max_frame_rate = balanced_settings_.MaxFps(input_state.video_codec_type(),
frame_size_pixels);
// Temporary fix for cases when there are fewer framerate adaptation steps
// up than down. Make number of down/up steps equal.
if (max_frame_rate == std::numeric_limits<int>::max() &&
current_restrictions.counters.fps_adaptations > 1) {
// Do not unrestrict framerate to allow additional adaptation up steps.
RTC_LOG(LS_INFO) << "Modifying framerate due to remaining fps count.";
max_frame_rate -= current_restrictions.counters.fps_adaptations;
}
// In BALANCED, the max_frame_rate must be checked before proceeding. This
// is because the MaxFps might be the current Fps and so the balanced
// settings may want to scale up the resolution.
if (!CanIncreaseFrameRateTo(max_frame_rate,
current_restrictions.restrictions)) {
return Adaptation::Status::kLimitReached;
}
} else {
RTC_DCHECK_NOTREACHED();
max_frame_rate = GetHigherFrameRateThan(input_state.frames_per_second());
}
if (current_restrictions.counters.fps_adaptations == 1) {
RTC_LOG(LS_INFO) << "Removing framerate down-scaling setting.";
max_frame_rate = std::numeric_limits<int>::max();
}
if (!CanIncreaseFrameRateTo(max_frame_rate,
current_restrictions.restrictions)) {
return Adaptation::Status::kLimitReached;
}
RTC_LOG(LS_INFO) << "Scaling up framerate: " << max_frame_rate;
RestrictionsWithCounters new_restrictions = current_restrictions;
new_restrictions.restrictions.set_max_frame_rate(
max_frame_rate != std::numeric_limits<int>::max()
? absl::optional<double>(max_frame_rate)
: absl::nullopt);
--new_restrictions.counters.fps_adaptations;
RTC_DCHECK_GE(new_restrictions.counters.fps_adaptations, 0);
return new_restrictions;
}
Adaptation VideoStreamAdapter::GetAdaptDownResolution() {
RTC_DCHECK_RUN_ON(&sequence_checker_);
VideoStreamInputState input_state = input_state_provider_->InputState();
switch (degradation_preference_) {
case DegradationPreference::DISABLED:
return RestrictionsOrStateToAdaptation(
Adaptation::Status::kAdaptationDisabled, input_state);
case DegradationPreference::MAINTAIN_RESOLUTION:
return RestrictionsOrStateToAdaptation(Adaptation::Status::kLimitReached,
input_state);
case DegradationPreference::MAINTAIN_FRAMERATE:
return GetAdaptationDown();
case DegradationPreference::BALANCED: {
return RestrictionsOrStateToAdaptation(
GetAdaptDownResolutionStepForBalanced(input_state), input_state);
}
}
RTC_CHECK_NOTREACHED();
}
VideoStreamAdapter::RestrictionsOrState
VideoStreamAdapter::GetAdaptDownResolutionStepForBalanced(
const VideoStreamInputState& input_state) const {
// Adapt twice if the first adaptation did not decrease resolution.
auto first_step = GetAdaptationDownStep(input_state, current_restrictions_);
if (!absl::holds_alternative<RestrictionsWithCounters>(first_step)) {
return first_step;
}
auto first_restrictions = absl::get<RestrictionsWithCounters>(first_step);
if (first_restrictions.counters.resolution_adaptations >
current_restrictions_.counters.resolution_adaptations) {
return first_step;
}
// We didn't decrease resolution so force it; amend a resolution resuction
// to the existing framerate reduction in `first_restrictions`.
auto second_step = DecreaseResolution(input_state, first_restrictions);
if (absl::holds_alternative<RestrictionsWithCounters>(second_step)) {
return second_step;
}
// If the second step was not successful then settle for the first one.
return first_step;
}
void VideoStreamAdapter::ApplyAdaptation(
const Adaptation& adaptation,
rtc::scoped_refptr<Resource> resource) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
RTC_DCHECK_EQ(adaptation.validation_id_, adaptation_validation_id_);
if (adaptation.status() != Adaptation::Status::kValid)
return;
// Remember the input pixels and fps of this adaptation. Used to avoid
// adapting again before this adaptation has had an effect.
if (DidIncreaseResolution(current_restrictions_.restrictions,
adaptation.restrictions())) {
awaiting_frame_size_change_.emplace(
true, adaptation.input_state().frame_size_pixels().value());
} else if (DidDecreaseResolution(current_restrictions_.restrictions,
adaptation.restrictions())) {
awaiting_frame_size_change_.emplace(
false, adaptation.input_state().frame_size_pixels().value());
} else {
awaiting_frame_size_change_ = absl::nullopt;
}
current_restrictions_ = {adaptation.restrictions(), adaptation.counters()};
BroadcastVideoRestrictionsUpdate(adaptation.input_state(), resource);
}
Adaptation VideoStreamAdapter::GetAdaptationTo(
const VideoAdaptationCounters& counters,
const VideoSourceRestrictions& restrictions) {
// Adapts up/down from the current levels so counters are equal.
RTC_DCHECK_RUN_ON(&sequence_checker_);
VideoStreamInputState input_state = input_state_provider_->InputState();
return Adaptation(adaptation_validation_id_, restrictions, counters,
input_state);
}
void VideoStreamAdapter::BroadcastVideoRestrictionsUpdate(
const VideoStreamInputState& input_state,
const rtc::scoped_refptr<Resource>& resource) {
RTC_DCHECK_RUN_ON(&sequence_checker_);
VideoSourceRestrictions filtered = FilterRestrictionsByDegradationPreference(
source_restrictions(), degradation_preference_);
if (last_filtered_restrictions_ == filtered) {
return;
}
for (auto* restrictions_listener : restrictions_listeners_) {
restrictions_listener->OnVideoSourceRestrictionsUpdated(
filtered, current_restrictions_.counters, resource,
source_restrictions());
}
last_video_source_restrictions_ = current_restrictions_.restrictions;
last_filtered_restrictions_ = filtered;
}
bool VideoStreamAdapter::HasSufficientInputForAdaptation(
const VideoStreamInputState& input_state) const {
return input_state.HasInputFrameSizeAndFramesPerSecond() &&
(degradation_preference_ !=
DegradationPreference::MAINTAIN_RESOLUTION ||
input_state.frames_per_second() >= kMinFrameRateFps);
}
VideoStreamAdapter::AwaitingFrameSizeChange::AwaitingFrameSizeChange(
bool pixels_increased,
int frame_size_pixels)
: pixels_increased(pixels_increased),
frame_size_pixels(frame_size_pixels) {}
absl::optional<uint32_t> VideoStreamAdapter::GetSingleActiveLayerPixels(
const VideoCodec& codec) {
int num_active = 0;
absl::optional<uint32_t> pixels;
if (codec.codecType == VideoCodecType::kVideoCodecVP9) {
for (int i = 0; i < codec.VP9().numberOfSpatialLayers; ++i) {
if (codec.spatialLayers[i].active) {
++num_active;
pixels = codec.spatialLayers[i].width * codec.spatialLayers[i].height;
}
}
} else {
for (int i = 0; i < codec.numberOfSimulcastStreams; ++i) {
if (codec.simulcastStream[i].active) {
++num_active;
pixels =
codec.simulcastStream[i].width * codec.simulcastStream[i].height;
}
}
}
return (num_active > 1) ? absl::nullopt : pixels;
}
} // namespace webrtc