modules/video_coding/rtp_vp8_ref_finder.cc - src - Git at Google

 /*
  *  Copyright (c) 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 "modules/video_coding/rtp_vp8_ref_finder.h"

 #include <utility>

 #include "rtc_base/logging.h"

 namespace webrtc {

 RtpFrameReferenceFinder::ReturnVector RtpVp8RefFinder::ManageFrame(
     std::unique_ptr<RtpFrameObject> frame) {
   FrameDecision decision = ManageFrameInternal(frame.get());

   RtpFrameReferenceFinder::ReturnVector res;
   switch (decision) {
     case kStash:
       if (stashed_frames_.size() > kMaxStashedFrames)
         stashed_frames_.pop_back();
       stashed_frames_.push_front(std::move(frame));
       return res;
     case kHandOff:
       res.push_back(std::move(frame));
       RetryStashedFrames(res);
       return res;
     case kDrop:
       return res;
   }

   return res;
 }

 RtpVp8RefFinder::FrameDecision RtpVp8RefFinder::ManageFrameInternal(
     RtpFrameObject* frame) {
   const RTPVideoHeader& video_header = frame->GetRtpVideoHeader();
   const RTPVideoHeaderVP8& codec_header =
       absl::get<RTPVideoHeaderVP8>(video_header.video_type_header);

   // Protect against corrupted packets with arbitrary large temporal idx.
   if (codec_header.temporalIdx >= kMaxTemporalLayers)
     return kDrop;

   frame->SetSpatialIndex(0);
   frame->SetId(codec_header.pictureId & 0x7FFF);

   if (last_picture_id_ == -1)
     last_picture_id_ = frame->Id();

   // Clean up info about not yet received frames that are too old.
   uint16_t old_picture_id =
       Subtract<kFrameIdLength>(frame->Id(), kMaxNotYetReceivedFrames);
   auto clean_frames_to = not_yet_received_frames_.lower_bound(old_picture_id);
   not_yet_received_frames_.erase(not_yet_received_frames_.begin(),
                                  clean_frames_to);
   // Avoid re-adding picture ids that were just erased.
   if (AheadOf<uint16_t, kFrameIdLength>(old_picture_id, last_picture_id_)) {
     last_picture_id_ = old_picture_id;
   }
   // Find if there has been a gap in fully received frames and save the picture
   // id of those frames in `not_yet_received_frames_`.
   if (AheadOf<uint16_t, kFrameIdLength>(frame->Id(), last_picture_id_)) {
     do {
       last_picture_id_ = Add<kFrameIdLength>(last_picture_id_, 1);
       not_yet_received_frames_.insert(last_picture_id_);
     } while (last_picture_id_ != frame->Id());
   }

   int64_t unwrapped_tl0 = tl0_unwrapper_.Unwrap(codec_header.tl0PicIdx & 0xFF);

   // Clean up info for base layers that are too old.
   int64_t old_tl0_pic_idx = unwrapped_tl0 - kMaxLayerInfo;
   auto clean_layer_info_to = layer_info_.lower_bound(old_tl0_pic_idx);
   layer_info_.erase(layer_info_.begin(), clean_layer_info_to);

   if (frame->frame_type() == VideoFrameType::kVideoFrameKey) {
     if (codec_header.temporalIdx != 0) {
       return kDrop;
     }
     frame->num_references = 0;
     layer_info_[unwrapped_tl0].fill(-1);
     UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
     return kHandOff;
   }

   auto layer_info_it = layer_info_.find(
       codec_header.temporalIdx == 0 ? unwrapped_tl0 - 1 : unwrapped_tl0);

   // If we don't have the base layer frame yet, stash this frame.
   if (layer_info_it == layer_info_.end())
     return kStash;

   // A non keyframe base layer frame has been received, copy the layer info
   // from the previous base layer frame and set a reference to the previous
   // base layer frame.
   if (codec_header.temporalIdx == 0) {
     layer_info_it =
         layer_info_.emplace(unwrapped_tl0, layer_info_it->second).first;
     frame->num_references = 1;
     int64_t last_pid_on_layer = layer_info_it->second[0];

     // Is this an old frame that has already been used to update the state? If
     // so, drop it.
     if (AheadOrAt<uint16_t, kFrameIdLength>(last_pid_on_layer, frame->Id())) {
       return kDrop;
     }

     frame->references[0] = last_pid_on_layer;
     UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
     return kHandOff;
   }

   // Layer sync frame, this frame only references its base layer frame.
   if (codec_header.layerSync) {
     frame->num_references = 1;
     int64_t last_pid_on_layer = layer_info_it->second[codec_header.temporalIdx];

     // Is this an old frame that has already been used to update the state? If
     // so, drop it.
     if (last_pid_on_layer != -1 &&
         AheadOrAt<uint16_t, kFrameIdLength>(last_pid_on_layer, frame->Id())) {
       return kDrop;
     }

     frame->references[0] = layer_info_it->second[0];
     UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
     return kHandOff;
   }

   // Find all references for this frame.
   frame->num_references = 0;
   for (uint8_t layer = 0; layer <= codec_header.temporalIdx; ++layer) {
     // If we have not yet received a previous frame on this temporal layer,
     // stash this frame.
     if (layer_info_it->second[layer] == -1)
       return kStash;

     // If the last frame on this layer is ahead of this frame it means that
     // a layer sync frame has been received after this frame for the same
     // base layer frame, drop this frame.
     if (AheadOf<uint16_t, kFrameIdLength>(layer_info_it->second[layer],
                                           frame->Id())) {
       return kDrop;
     }

     // If we have not yet received a frame between this frame and the referenced
     // frame then we have to wait for that frame to be completed first.
     auto not_received_frame_it =
         not_yet_received_frames_.upper_bound(layer_info_it->second[layer]);
     if (not_received_frame_it != not_yet_received_frames_.end() &&
         AheadOf<uint16_t, kFrameIdLength>(frame->Id(),
                                           *not_received_frame_it)) {
       return kStash;
     }

     if (!(AheadOf<uint16_t, kFrameIdLength>(frame->Id(),
                                             layer_info_it->second[layer]))) {
       RTC_LOG(LS_WARNING) << "Frame with picture id " << frame->Id()
                           << " and packet range [" << frame->first_seq_num()
                           << ", " << frame->last_seq_num()
                           << "] already received, "
                              " dropping frame.";
       return kDrop;
     }

     ++frame->num_references;
     frame->references[layer] = layer_info_it->second[layer];
   }

   UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
   return kHandOff;
 }

 void RtpVp8RefFinder::UpdateLayerInfoVp8(RtpFrameObject* frame,
                                          int64_t unwrapped_tl0,
                                          uint8_t temporal_idx) {
   auto layer_info_it = layer_info_.find(unwrapped_tl0);

   // Update this layer info and newer.
   while (layer_info_it != layer_info_.end()) {
     if (layer_info_it->second[temporal_idx] != -1 &&
         AheadOf<uint16_t, kFrameIdLength>(layer_info_it->second[temporal_idx],
                                           frame->Id())) {
       // The frame was not newer, then no subsequent layer info have to be
       // update.
       break;
     }

     layer_info_it->second[temporal_idx] = frame->Id();
     ++unwrapped_tl0;
     layer_info_it = layer_info_.find(unwrapped_tl0);
   }
   not_yet_received_frames_.erase(frame->Id());

   UnwrapPictureIds(frame);
 }

 void RtpVp8RefFinder::RetryStashedFrames(
     RtpFrameReferenceFinder::ReturnVector& res) {
   bool complete_frame = false;
   do {
     complete_frame = false;
     for (auto frame_it = stashed_frames_.begin();
          frame_it != stashed_frames_.end();) {
       FrameDecision decision = ManageFrameInternal(frame_it->get());

       switch (decision) {
         case kStash:
           ++frame_it;
           break;
         case kHandOff:
           complete_frame = true;
           res.push_back(std::move(*frame_it));
           ABSL_FALLTHROUGH_INTENDED;
         case kDrop:
           frame_it = stashed_frames_.erase(frame_it);
       }
     }
   } while (complete_frame);
 }

 void RtpVp8RefFinder::UnwrapPictureIds(RtpFrameObject* frame) {
   for (size_t i = 0; i < frame->num_references; ++i)
     frame->references[i] = unwrapper_.Unwrap(frame->references[i]);
   frame->SetId(unwrapper_.Unwrap(frame->Id()));
 }

 void RtpVp8RefFinder::ClearTo(uint16_t seq_num) {
   auto it = stashed_frames_.begin();
   while (it != stashed_frames_.end()) {
     if (AheadOf<uint16_t>(seq_num, (*it)->first_seq_num())) {
       it = stashed_frames_.erase(it);
     } else {
       ++it;
     }
   }
 }

 }  // namespace webrtc
	/*
	* Copyright (c) 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 "modules/video_coding/rtp_vp8_ref_finder.h"

	#include <utility>

	#include "rtc_base/logging.h"

	namespace webrtc {

	RtpFrameReferenceFinder::ReturnVector RtpVp8RefFinder::ManageFrame(
	std::unique_ptr<RtpFrameObject> frame) {
	FrameDecision decision = ManageFrameInternal(frame.get());

	RtpFrameReferenceFinder::ReturnVector res;
	switch (decision) {
	case kStash:
	if (stashed_frames_.size() > kMaxStashedFrames)
	stashed_frames_.pop_back();
	stashed_frames_.push_front(std::move(frame));
	return res;
	case kHandOff:
	res.push_back(std::move(frame));
	RetryStashedFrames(res);
	return res;
	case kDrop:
	return res;
	}

	return res;
	}

	RtpVp8RefFinder::FrameDecision RtpVp8RefFinder::ManageFrameInternal(
	RtpFrameObject* frame) {
	const RTPVideoHeader& video_header = frame->GetRtpVideoHeader();
	const RTPVideoHeaderVP8& codec_header =
	absl::get<RTPVideoHeaderVP8>(video_header.video_type_header);

	// Protect against corrupted packets with arbitrary large temporal idx.
	if (codec_header.temporalIdx >= kMaxTemporalLayers)
	return kDrop;

	frame->SetSpatialIndex(0);
	frame->SetId(codec_header.pictureId & 0x7FFF);

	if (last_picture_id_ == -1)
	last_picture_id_ = frame->Id();

	// Clean up info about not yet received frames that are too old.
	uint16_t old_picture_id =
	Subtract<kFrameIdLength>(frame->Id(), kMaxNotYetReceivedFrames);
	auto clean_frames_to = not_yet_received_frames_.lower_bound(old_picture_id);
	not_yet_received_frames_.erase(not_yet_received_frames_.begin(),
	clean_frames_to);
	// Avoid re-adding picture ids that were just erased.
	if (AheadOf<uint16_t, kFrameIdLength>(old_picture_id, last_picture_id_)) {
	last_picture_id_ = old_picture_id;
	}
	// Find if there has been a gap in fully received frames and save the picture
	// id of those frames in `not_yet_received_frames_`.
	if (AheadOf<uint16_t, kFrameIdLength>(frame->Id(), last_picture_id_)) {
	do {
	last_picture_id_ = Add<kFrameIdLength>(last_picture_id_, 1);
	not_yet_received_frames_.insert(last_picture_id_);
	} while (last_picture_id_ != frame->Id());
	}

	int64_t unwrapped_tl0 = tl0_unwrapper_.Unwrap(codec_header.tl0PicIdx & 0xFF);

	// Clean up info for base layers that are too old.
	int64_t old_tl0_pic_idx = unwrapped_tl0 - kMaxLayerInfo;
	auto clean_layer_info_to = layer_info_.lower_bound(old_tl0_pic_idx);
	layer_info_.erase(layer_info_.begin(), clean_layer_info_to);

	if (frame->frame_type() == VideoFrameType::kVideoFrameKey) {
	if (codec_header.temporalIdx != 0) {
	return kDrop;
	}
	frame->num_references = 0;
	layer_info_[unwrapped_tl0].fill(-1);
	UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
	return kHandOff;
	}

	auto layer_info_it = layer_info_.find(
	codec_header.temporalIdx == 0 ? unwrapped_tl0 - 1 : unwrapped_tl0);

	// If we don't have the base layer frame yet, stash this frame.
	if (layer_info_it == layer_info_.end())
	return kStash;

	// A non keyframe base layer frame has been received, copy the layer info
	// from the previous base layer frame and set a reference to the previous
	// base layer frame.
	if (codec_header.temporalIdx == 0) {
	layer_info_it =
	layer_info_.emplace(unwrapped_tl0, layer_info_it->second).first;
	frame->num_references = 1;
	int64_t last_pid_on_layer = layer_info_it->second[0];

	// Is this an old frame that has already been used to update the state? If
	// so, drop it.
	if (AheadOrAt<uint16_t, kFrameIdLength>(last_pid_on_layer, frame->Id())) {
	return kDrop;
	}

	frame->references[0] = last_pid_on_layer;
	UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
	return kHandOff;
	}

	// Layer sync frame, this frame only references its base layer frame.
	if (codec_header.layerSync) {
	frame->num_references = 1;
	int64_t last_pid_on_layer = layer_info_it->second[codec_header.temporalIdx];

	// Is this an old frame that has already been used to update the state? If
	// so, drop it.
	if (last_pid_on_layer != -1 &&
	AheadOrAt<uint16_t, kFrameIdLength>(last_pid_on_layer, frame->Id())) {
	return kDrop;
	}

	frame->references[0] = layer_info_it->second[0];
	UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
	return kHandOff;
	}

	// Find all references for this frame.
	frame->num_references = 0;
	for (uint8_t layer = 0; layer <= codec_header.temporalIdx; ++layer) {
	// If we have not yet received a previous frame on this temporal layer,
	// stash this frame.
	if (layer_info_it->second[layer] == -1)
	return kStash;

	// If the last frame on this layer is ahead of this frame it means that
	// a layer sync frame has been received after this frame for the same
	// base layer frame, drop this frame.
	if (AheadOf<uint16_t, kFrameIdLength>(layer_info_it->second[layer],
	frame->Id())) {
	return kDrop;
	}

	// If we have not yet received a frame between this frame and the referenced
	// frame then we have to wait for that frame to be completed first.
	auto not_received_frame_it =
	not_yet_received_frames_.upper_bound(layer_info_it->second[layer]);
	if (not_received_frame_it != not_yet_received_frames_.end() &&
	AheadOf<uint16_t, kFrameIdLength>(frame->Id(),
	*not_received_frame_it)) {
	return kStash;
	}

	if (!(AheadOf<uint16_t, kFrameIdLength>(frame->Id(),
	layer_info_it->second[layer]))) {
	RTC_LOG(LS_WARNING) << "Frame with picture id " << frame->Id()
	<< " and packet range [" << frame->first_seq_num()
	<< ", " << frame->last_seq_num()
	<< "] already received, "
	" dropping frame.";
	return kDrop;
	}

	++frame->num_references;
	frame->references[layer] = layer_info_it->second[layer];
	}

	UpdateLayerInfoVp8(frame, unwrapped_tl0, codec_header.temporalIdx);
	return kHandOff;
	}

	void RtpVp8RefFinder::UpdateLayerInfoVp8(RtpFrameObject* frame,
	int64_t unwrapped_tl0,
	uint8_t temporal_idx) {
	auto layer_info_it = layer_info_.find(unwrapped_tl0);

	// Update this layer info and newer.
	while (layer_info_it != layer_info_.end()) {
	if (layer_info_it->second[temporal_idx] != -1 &&
	AheadOf<uint16_t, kFrameIdLength>(layer_info_it->second[temporal_idx],
	frame->Id())) {
	// The frame was not newer, then no subsequent layer info have to be
	// update.
	break;
	}

	layer_info_it->second[temporal_idx] = frame->Id();
	++unwrapped_tl0;
	layer_info_it = layer_info_.find(unwrapped_tl0);
	}
	not_yet_received_frames_.erase(frame->Id());

	UnwrapPictureIds(frame);
	}

	void RtpVp8RefFinder::RetryStashedFrames(
	RtpFrameReferenceFinder::ReturnVector& res) {
	bool complete_frame = false;
	do {
	complete_frame = false;
	for (auto frame_it = stashed_frames_.begin();
	frame_it != stashed_frames_.end();) {
	FrameDecision decision = ManageFrameInternal(frame_it->get());

	switch (decision) {
	case kStash:
	++frame_it;
	break;
	case kHandOff:
	complete_frame = true;
	res.push_back(std::move(*frame_it));
	ABSL_FALLTHROUGH_INTENDED;
	case kDrop:
	frame_it = stashed_frames_.erase(frame_it);
	}
	}
	} while (complete_frame);
	}

	void RtpVp8RefFinder::UnwrapPictureIds(RtpFrameObject* frame) {
	for (size_t i = 0; i < frame->num_references; ++i)
	frame->references[i] = unwrapper_.Unwrap(frame->references[i]);
	frame->SetId(unwrapper_.Unwrap(frame->Id()));
	}

	void RtpVp8RefFinder::ClearTo(uint16_t seq_num) {
	auto it = stashed_frames_.begin();
	while (it != stashed_frames_.end()) {
	if (AheadOf<uint16_t>(seq_num, (*it)->first_seq_num())) {
	it = stashed_frames_.erase(it);
	} else {
	++it;
	}
	}
	}

	} // namespace webrtc