api/video/frame_buffer.cc - src - Git at Google

 /*
  *  Copyright (c) 2021 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 "api/video/frame_buffer.h"

 #include <algorithm>

 #include "absl/algorithm/container.h"
 #include "absl/container/inlined_vector.h"
 #include "rtc_base/logging.h"
 #include "rtc_base/numerics/sequence_number_util.h"

 namespace webrtc {
 namespace {
 bool ValidReferences(const EncodedFrame& frame) {
   // All references must point backwards, and duplicates are not allowed.
   for (size_t i = 0; i < frame.num_references; ++i) {
     if (frame.references[i] >= frame.Id())
       return false;

     for (size_t j = i + 1; j < frame.num_references; ++j) {
       if (frame.references[i] == frame.references[j])
         return false;
     }
   }

   return true;
 }

 // Since FrameBuffer::FrameInfo is private it can't be used in the function
 // signature, hence the FrameIteratorT type.
 template <typename FrameIteratorT>
 rtc::ArrayView<const int64_t> GetReferences(const FrameIteratorT& it) {
   return {it->second.encoded_frame->references,
           std::min<size_t>(it->second.encoded_frame->num_references,
                            EncodedFrame::kMaxFrameReferences)};
 }

 template <typename FrameIteratorT>
 int64_t GetFrameId(const FrameIteratorT& it) {
   return it->first;
 }

 template <typename FrameIteratorT>
 uint32_t GetTimestamp(const FrameIteratorT& it) {
   return it->second.encoded_frame->Timestamp();
 }

 template <typename FrameIteratorT>
 bool IsLastFrameInTemporalUnit(const FrameIteratorT& it) {
   return it->second.encoded_frame->is_last_spatial_layer;
 }
 }  // namespace

 FrameBuffer::FrameBuffer(int max_size,
                          int max_decode_history,
                          const FieldTrialsView& field_trials)
     : legacy_frame_id_jump_behavior_(
           !field_trials.IsDisabled("WebRTC-LegacyFrameIdJumpBehavior")),
       max_size_(max_size),
       decoded_frame_history_(max_decode_history) {}

 bool FrameBuffer::InsertFrame(std::unique_ptr<EncodedFrame> frame) {
   if (!ValidReferences(*frame)) {
     RTC_DLOG(LS_WARNING) << "Frame " << frame->Id()
                          << " has invalid references, dropping frame.";
     return false;
   }

   if (frame->Id() <= decoded_frame_history_.GetLastDecodedFrameId()) {
     if (legacy_frame_id_jump_behavior_ && frame->is_keyframe() &&
         AheadOf(frame->Timestamp(),
                 *decoded_frame_history_.GetLastDecodedFrameTimestamp())) {
       RTC_DLOG(LS_WARNING)
           << "Keyframe " << frame->Id()
           << " has newer timestamp but older picture id, clearing buffer.";
       Clear();
     } else {
       // Already decoded past this frame.
       return false;
     }
   }

   if (frames_.size() == max_size_) {
     if (frame->is_keyframe()) {
       RTC_DLOG(LS_WARNING) << "Keyframe " << frame->Id()
                            << " inserted into full buffer, clearing buffer.";
       Clear();
     } else {
       // No space for this frame.
       return false;
     }
   }

   const int64_t frame_id = frame->Id();
   auto insert_res = frames_.emplace(frame_id, FrameInfo{std::move(frame)});
   if (!insert_res.second) {
     // Frame has already been inserted.
     return false;
   }

   if (frames_.size() == max_size_) {
     RTC_DLOG(LS_WARNING) << "Frame " << frame_id
                          << " inserted, buffer is now full.";
   }

   PropagateContinuity(insert_res.first);
   FindNextAndLastDecodableTemporalUnit();
   return true;
 }

 absl::InlinedVector<std::unique_ptr<EncodedFrame>, 4>
 FrameBuffer::ExtractNextDecodableTemporalUnit() {
   absl::InlinedVector<std::unique_ptr<EncodedFrame>, 4> res;
   if (!next_decodable_temporal_unit_) {
     return res;
   }

   auto end_it = std::next(next_decodable_temporal_unit_->last_frame);
   for (auto it = next_decodable_temporal_unit_->first_frame; it != end_it;
        ++it) {
     decoded_frame_history_.InsertDecoded(GetFrameId(it), GetTimestamp(it));
     res.push_back(std::move(it->second.encoded_frame));
   }

   DropNextDecodableTemporalUnit();
   return res;
 }

 void FrameBuffer::DropNextDecodableTemporalUnit() {
   if (!next_decodable_temporal_unit_) {
     return;
   }

   auto end_it = std::next(next_decodable_temporal_unit_->last_frame);
   num_dropped_frames_ += std::count_if(
       frames_.begin(), end_it,
       [](const auto& f) { return f.second.encoded_frame != nullptr; });

   frames_.erase(frames_.begin(), end_it);
   FindNextAndLastDecodableTemporalUnit();
 }

 absl::optional<int64_t> FrameBuffer::LastContinuousFrameId() const {
   return last_continuous_frame_id_;
 }

 absl::optional<int64_t> FrameBuffer::LastContinuousTemporalUnitFrameId() const {
   return last_continuous_temporal_unit_frame_id_;
 }

 absl::optional<FrameBuffer::DecodabilityInfo>
 FrameBuffer::DecodableTemporalUnitsInfo() const {
   return decodable_temporal_units_info_;
 }

 int FrameBuffer::GetTotalNumberOfContinuousTemporalUnits() const {
   return num_continuous_temporal_units_;
 }
 int FrameBuffer::GetTotalNumberOfDroppedFrames() const {
   return num_dropped_frames_;
 }

 size_t FrameBuffer::CurrentSize() const {
   return frames_.size();
 }

 bool FrameBuffer::IsContinuous(const FrameIterator& it) const {
   for (int64_t reference : GetReferences(it)) {
     if (decoded_frame_history_.WasDecoded(reference)) {
       continue;
     }

     auto reference_frame_it = frames_.find(reference);
     if (reference_frame_it != frames_.end() &&
         reference_frame_it->second.continuous) {
       continue;
     }

     return false;
   }

   return true;
 }

 void FrameBuffer::PropagateContinuity(const FrameIterator& frame_it) {
   for (auto it = frame_it; it != frames_.end(); ++it) {
     if (!it->second.continuous) {
       if (IsContinuous(it)) {
         it->second.continuous = true;
         if (last_continuous_frame_id_ < GetFrameId(it)) {
           last_continuous_frame_id_ = GetFrameId(it);
         }
         if (IsLastFrameInTemporalUnit(it)) {
           num_continuous_temporal_units_++;
           if (last_continuous_temporal_unit_frame_id_ < GetFrameId(it)) {
             last_continuous_temporal_unit_frame_id_ = GetFrameId(it);
           }
         }
       }
     }
   }
 }

 void FrameBuffer::FindNextAndLastDecodableTemporalUnit() {
   next_decodable_temporal_unit_.reset();
   decodable_temporal_units_info_.reset();

   if (!last_continuous_temporal_unit_frame_id_) {
     return;
   }

   FrameIterator first_frame_it = frames_.begin();
   FrameIterator last_frame_it = frames_.begin();
   absl::InlinedVector<int64_t, 4> frames_in_temporal_unit;
   uint32_t last_decodable_temporal_unit_timestamp;
   for (auto frame_it = frames_.begin(); frame_it != frames_.end();) {
     if (GetFrameId(frame_it) > *last_continuous_temporal_unit_frame_id_) {
       break;
     }

     if (GetTimestamp(frame_it) != GetTimestamp(first_frame_it)) {
       frames_in_temporal_unit.clear();
       first_frame_it = frame_it;
     }

     frames_in_temporal_unit.push_back(GetFrameId(frame_it));

     last_frame_it = frame_it++;

     if (IsLastFrameInTemporalUnit(last_frame_it)) {
       bool temporal_unit_decodable = true;
       for (auto it = first_frame_it; it != frame_it && temporal_unit_decodable;
            ++it) {
         for (int64_t reference : GetReferences(it)) {
           if (!decoded_frame_history_.WasDecoded(reference) &&
               !absl::c_linear_search(frames_in_temporal_unit, reference)) {
             // A frame in the temporal unit has a non-decoded reference outside
             // the temporal unit, so it's not yet ready to be decoded.
             temporal_unit_decodable = false;
             break;
           }
         }
       }

       if (temporal_unit_decodable) {
         if (!next_decodable_temporal_unit_) {
           next_decodable_temporal_unit_ = {first_frame_it, last_frame_it};
         }

         last_decodable_temporal_unit_timestamp = GetTimestamp(first_frame_it);
       }
     }
   }

   if (next_decodable_temporal_unit_) {
     decodable_temporal_units_info_ = {
         .next_rtp_timestamp =
             GetTimestamp(next_decodable_temporal_unit_->first_frame),
         .last_rtp_timestamp = last_decodable_temporal_unit_timestamp};
   }
 }

 void FrameBuffer::Clear() {
   frames_.clear();
   next_decodable_temporal_unit_.reset();
   decodable_temporal_units_info_.reset();
   last_continuous_frame_id_.reset();
   last_continuous_temporal_unit_frame_id_.reset();
   decoded_frame_history_.Clear();
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 2021 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 "api/video/frame_buffer.h"

	#include <algorithm>

	#include "absl/algorithm/container.h"
	#include "absl/container/inlined_vector.h"
	#include "rtc_base/logging.h"
	#include "rtc_base/numerics/sequence_number_util.h"

	namespace webrtc {
	namespace {
	bool ValidReferences(const EncodedFrame& frame) {
	// All references must point backwards, and duplicates are not allowed.
	for (size_t i = 0; i < frame.num_references; ++i) {
	if (frame.references[i] >= frame.Id())
	return false;

	for (size_t j = i + 1; j < frame.num_references; ++j) {
	if (frame.references[i] == frame.references[j])
	return false;
	}
	}

	return true;
	}

	// Since FrameBuffer::FrameInfo is private it can't be used in the function
	// signature, hence the FrameIteratorT type.
	template <typename FrameIteratorT>
	rtc::ArrayView<const int64_t> GetReferences(const FrameIteratorT& it) {
	return {it->second.encoded_frame->references,
	std::min<size_t>(it->second.encoded_frame->num_references,
	EncodedFrame::kMaxFrameReferences)};
	}

	template <typename FrameIteratorT>
	int64_t GetFrameId(const FrameIteratorT& it) {
	return it->first;
	}

	template <typename FrameIteratorT>
	uint32_t GetTimestamp(const FrameIteratorT& it) {
	return it->second.encoded_frame->Timestamp();
	}

	template <typename FrameIteratorT>
	bool IsLastFrameInTemporalUnit(const FrameIteratorT& it) {
	return it->second.encoded_frame->is_last_spatial_layer;
	}
	} // namespace

	FrameBuffer::FrameBuffer(int max_size,
	int max_decode_history,
	const FieldTrialsView& field_trials)
	: legacy_frame_id_jump_behavior_(
	!field_trials.IsDisabled("WebRTC-LegacyFrameIdJumpBehavior")),
	max_size_(max_size),
	decoded_frame_history_(max_decode_history) {}

	bool FrameBuffer::InsertFrame(std::unique_ptr<EncodedFrame> frame) {
	if (!ValidReferences(*frame)) {
	RTC_DLOG(LS_WARNING) << "Frame " << frame->Id()
	<< " has invalid references, dropping frame.";
	return false;
	}

	if (frame->Id() <= decoded_frame_history_.GetLastDecodedFrameId()) {
	if (legacy_frame_id_jump_behavior_ && frame->is_keyframe() &&
	AheadOf(frame->Timestamp(),
	*decoded_frame_history_.GetLastDecodedFrameTimestamp())) {
	RTC_DLOG(LS_WARNING)
	<< "Keyframe " << frame->Id()
	<< " has newer timestamp but older picture id, clearing buffer.";
	Clear();
	} else {
	// Already decoded past this frame.
	return false;
	}
	}

	if (frames_.size() == max_size_) {
	if (frame->is_keyframe()) {
	RTC_DLOG(LS_WARNING) << "Keyframe " << frame->Id()
	<< " inserted into full buffer, clearing buffer.";
	Clear();
	} else {
	// No space for this frame.
	return false;
	}
	}

	const int64_t frame_id = frame->Id();
	auto insert_res = frames_.emplace(frame_id, FrameInfo{std::move(frame)});
	if (!insert_res.second) {
	// Frame has already been inserted.
	return false;
	}

	if (frames_.size() == max_size_) {
	RTC_DLOG(LS_WARNING) << "Frame " << frame_id
	<< " inserted, buffer is now full.";
	}

	PropagateContinuity(insert_res.first);
	FindNextAndLastDecodableTemporalUnit();
	return true;
	}

	absl::InlinedVector<std::unique_ptr<EncodedFrame>, 4>
	FrameBuffer::ExtractNextDecodableTemporalUnit() {
	absl::InlinedVector<std::unique_ptr<EncodedFrame>, 4> res;
	if (!next_decodable_temporal_unit_) {
	return res;
	}

	auto end_it = std::next(next_decodable_temporal_unit_->last_frame);
	for (auto it = next_decodable_temporal_unit_->first_frame; it != end_it;
	++it) {
	decoded_frame_history_.InsertDecoded(GetFrameId(it), GetTimestamp(it));
	res.push_back(std::move(it->second.encoded_frame));
	}

	DropNextDecodableTemporalUnit();
	return res;
	}

	void FrameBuffer::DropNextDecodableTemporalUnit() {
	if (!next_decodable_temporal_unit_) {
	return;
	}

	auto end_it = std::next(next_decodable_temporal_unit_->last_frame);
	num_dropped_frames_ += std::count_if(
	frames_.begin(), end_it,
	[](const auto& f) { return f.second.encoded_frame != nullptr; });

	frames_.erase(frames_.begin(), end_it);
	FindNextAndLastDecodableTemporalUnit();
	}

	absl::optional<int64_t> FrameBuffer::LastContinuousFrameId() const {
	return last_continuous_frame_id_;
	}

	absl::optional<int64_t> FrameBuffer::LastContinuousTemporalUnitFrameId() const {
	return last_continuous_temporal_unit_frame_id_;
	}

	absl::optional<FrameBuffer::DecodabilityInfo>
	FrameBuffer::DecodableTemporalUnitsInfo() const {
	return decodable_temporal_units_info_;
	}

	int FrameBuffer::GetTotalNumberOfContinuousTemporalUnits() const {
	return num_continuous_temporal_units_;
	}
	int FrameBuffer::GetTotalNumberOfDroppedFrames() const {
	return num_dropped_frames_;
	}

	size_t FrameBuffer::CurrentSize() const {
	return frames_.size();
	}

	bool FrameBuffer::IsContinuous(const FrameIterator& it) const {
	for (int64_t reference : GetReferences(it)) {
	if (decoded_frame_history_.WasDecoded(reference)) {
	continue;
	}

	auto reference_frame_it = frames_.find(reference);
	if (reference_frame_it != frames_.end() &&
	reference_frame_it->second.continuous) {
	continue;
	}

	return false;
	}

	return true;
	}

	void FrameBuffer::PropagateContinuity(const FrameIterator& frame_it) {
	for (auto it = frame_it; it != frames_.end(); ++it) {
	if (!it->second.continuous) {
	if (IsContinuous(it)) {
	it->second.continuous = true;
	if (last_continuous_frame_id_ < GetFrameId(it)) {
	last_continuous_frame_id_ = GetFrameId(it);
	}
	if (IsLastFrameInTemporalUnit(it)) {
	num_continuous_temporal_units_++;
	if (last_continuous_temporal_unit_frame_id_ < GetFrameId(it)) {
	last_continuous_temporal_unit_frame_id_ = GetFrameId(it);
	}
	}
	}
	}
	}
	}

	void FrameBuffer::FindNextAndLastDecodableTemporalUnit() {
	next_decodable_temporal_unit_.reset();
	decodable_temporal_units_info_.reset();

	if (!last_continuous_temporal_unit_frame_id_) {
	return;
	}

	FrameIterator first_frame_it = frames_.begin();
	FrameIterator last_frame_it = frames_.begin();
	absl::InlinedVector<int64_t, 4> frames_in_temporal_unit;
	uint32_t last_decodable_temporal_unit_timestamp;
	for (auto frame_it = frames_.begin(); frame_it != frames_.end();) {
	if (GetFrameId(frame_it) > *last_continuous_temporal_unit_frame_id_) {
	break;
	}

	if (GetTimestamp(frame_it) != GetTimestamp(first_frame_it)) {
	frames_in_temporal_unit.clear();
	first_frame_it = frame_it;
	}

	frames_in_temporal_unit.push_back(GetFrameId(frame_it));

	last_frame_it = frame_it++;

	if (IsLastFrameInTemporalUnit(last_frame_it)) {
	bool temporal_unit_decodable = true;
	for (auto it = first_frame_it; it != frame_it && temporal_unit_decodable;
	++it) {
	for (int64_t reference : GetReferences(it)) {
	if (!decoded_frame_history_.WasDecoded(reference) &&
	!absl::c_linear_search(frames_in_temporal_unit, reference)) {
	// A frame in the temporal unit has a non-decoded reference outside
	// the temporal unit, so it's not yet ready to be decoded.
	temporal_unit_decodable = false;
	break;
	}
	}
	}

	if (temporal_unit_decodable) {
	if (!next_decodable_temporal_unit_) {
	next_decodable_temporal_unit_ = {first_frame_it, last_frame_it};
	}

	last_decodable_temporal_unit_timestamp = GetTimestamp(first_frame_it);
	}
	}
	}

	if (next_decodable_temporal_unit_) {
	decodable_temporal_units_info_ = {
	.next_rtp_timestamp =
	GetTimestamp(next_decodable_temporal_unit_->first_frame),
	.last_rtp_timestamp = last_decodable_temporal_unit_timestamp};
	}
	}

	void FrameBuffer::Clear() {
	frames_.clear();
	next_decodable_temporal_unit_.reset();
	decodable_temporal_units_info_.reset();
	last_continuous_frame_id_.reset();
	last_continuous_temporal_unit_frame_id_.reset();
	decoded_frame_history_.Clear();
	}

	} // namespace webrtc