Stashed frames are now retried in a loop rather than recursively.

webrtc/modules/video_coding/rtp_frame_reference_finder.cc

 /*
  *  Copyright (c) 2016 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.
  */
 
@@ skipping 21 matching lines @@
 void RtpFrameReferenceFinder::ManageFrame(
     std::unique_ptr<RtpFrameObject> frame) {
   rtc::CritScope lock(&crit_);
 
   // If we have cleared past this frame, drop it.
   if (cleared_to_seq_num_ != -1 &&
       AheadOf<uint16_t>(cleared_to_seq_num_, frame->first_seq_num())) {
     return;
   }
 
+  FrameDecision decision = ManageFrameInternal(frame.get());
+
+  switch (decision) {
+    case kStash:
+      if (stashed_frames_.size() > kMaxStashedFrames)
+        stashed_frames_.pop_back();
+      stashed_frames_.push_front(std::move(frame));
+      break;
+    case kHandOff:
+      frame_callback_->OnCompleteFrame(std::move(frame));
+      RetryStashedFrames();
+      break;
+    case kDrop:
+      break;
+  }
+}
+
+void RtpFrameReferenceFinder::RetryStashedFrames() {
+  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;
+          frame_callback_->OnCompleteFrame(std::move(*frame_it));
+          FALLTHROUGH();
+        case kDrop:
+          frame_it = stashed_frames_.erase(frame_it);
+      }
+    }
+  } while (complete_frame);
+}
+
+RtpFrameReferenceFinder::FrameDecision
+RtpFrameReferenceFinder::ManageFrameInternal(RtpFrameObject* frame) {
   switch (frame->codec_type()) {
     case kVideoCodecFlexfec:
     case kVideoCodecULPFEC:
     case kVideoCodecRED:
       RTC_NOTREACHED();
       break;
     case kVideoCodecVP8:
-      ManageFrameVp8(std::move(frame));
-      break;
+      return ManageFrameVp8(frame);
     case kVideoCodecVP9:
-      ManageFrameVp9(std::move(frame));
-      break;
+      return ManageFrameVp9(frame);
     // Since the EndToEndTests use kVicdeoCodecUnknow we treat it the same as
     // kVideoCodecGeneric.
     // TODO(philipel): Take a look at the EndToEndTests and see if maybe they
     //                 should be changed to use kVideoCodecGeneric instead.
     case kVideoCodecUnknown:
     case kVideoCodecH264:
     case kVideoCodecI420:
     case kVideoCodecGeneric:
-      ManageFrameGeneric(std::move(frame), kNoPictureId);
-      break;
+      return ManageFrameGeneric(frame, kNoPictureId);
   }
+
+  // If not all code paths return a value it makes the win compiler sad.
+  RTC_NOTREACHED();
+  return kDrop;
 }
 
 void RtpFrameReferenceFinder::PaddingReceived(uint16_t seq_num) {
   rtc::CritScope lock(&crit_);
   auto clean_padding_to =
       stashed_padding_.lower_bound(seq_num - kMaxPaddingAge);
   stashed_padding_.erase(stashed_padding_.begin(), clean_padding_to);
   stashed_padding_.insert(seq_num);
   UpdateLastPictureIdWithPadding(seq_num);
   RetryStashedFrames();
@@ skipping 42 matching lines @@
   // for a while there is a risk that new frames will appear to be older than
   // the keyframe they belong to due to wrapping sequence number. In order
   // to prevent this we advance the picture id of the keyframe every so often.
   if (ForwardDiff(gop_seq_num_it->first, seq_num) > 10000) {
     RTC_DCHECK_EQ(1ul, last_seq_num_gop_.size());
     last_seq_num_gop_[seq_num] = gop_seq_num_it->second;
     last_seq_num_gop_.erase(gop_seq_num_it);
   }
 }
 
-void RtpFrameReferenceFinder::RetryStashedFrames() {
-  size_t num_stashed_frames = stashed_frames_.size();
-
-  // Clean up stashed frames if there are too many.
-  while (stashed_frames_.size() > kMaxStashedFrames)
-    stashed_frames_.pop_front();
-
-  // Since frames are stashed if there is not enough data to determine their
-  // frame references we should at most check |stashed_frames_.size()| in
-  // order to not pop and push frames in and endless loop.
-  // NOTE! This function may be called recursively, hence the
-  //       "!stashed_frames_.empty()" condition.
-  for (size_t i = 0; i < num_stashed_frames && !stashed_frames_.empty(); ++i) {
-    std::unique_ptr<RtpFrameObject> frame = std::move(stashed_frames_.front());
-    stashed_frames_.pop_front();
-    ManageFrame(std::move(frame));
-  }
-}
-
-void RtpFrameReferenceFinder::ManageFrameGeneric(
-    std::unique_ptr<RtpFrameObject> frame,
-    int picture_id) {
+RtpFrameReferenceFinder::FrameDecision
+RtpFrameReferenceFinder::ManageFrameGeneric(RtpFrameObject* frame,
+                                            int picture_id) {
   // If |picture_id| is specified then we use that to set the frame references,
   // otherwise we use sequence number.
   if (picture_id != kNoPictureId) {
     if (last_unwrap_ == -1)
       last_unwrap_ = picture_id;
 
     frame->picture_id = UnwrapPictureId(picture_id % kPicIdLength);
     frame->num_references = frame->frame_type() == kVideoFrameKey ? 0 : 1;
     frame->references[0] = frame->picture_id - 1;
-    frame_callback_->OnCompleteFrame(std::move(frame));
-    return;
+    return kHandOff;
   }
 
   if (frame->frame_type() == kVideoFrameKey) {
     last_seq_num_gop_.insert(std::make_pair(
         frame->last_seq_num(),
         std::make_pair(frame->last_seq_num(), frame->last_seq_num())));
   }
 
   // We have received a frame but not yet a keyframe, stash this frame.
-  if (last_seq_num_gop_.empty()) {
-    stashed_frames_.push_back(std::move(frame));
-    return;
-  }
+  if (last_seq_num_gop_.empty())
+    return kStash;
 
   // Clean up info for old keyframes but make sure to keep info
   // for the last keyframe.
   auto clean_to = last_seq_num_gop_.lower_bound(frame->last_seq_num() - 100);
   for (auto it = last_seq_num_gop_.begin();
        it != clean_to && last_seq_num_gop_.size() > 1;) {
     it = last_seq_num_gop_.erase(it);
   }
 
   // Find the last sequence number of the last frame for the keyframe
   // that this frame indirectly references.
   auto seq_num_it = last_seq_num_gop_.upper_bound(frame->last_seq_num());
   if (seq_num_it == last_seq_num_gop_.begin()) {
     LOG(LS_WARNING) << "Generic frame with packet range ["
                     << frame->first_seq_num() << ", " << frame->last_seq_num()
                     << "] has no GoP, dropping frame.";
-    return;
+    return kDrop;
   }
   seq_num_it--;
 
   // Make sure the packet sequence numbers are continuous, otherwise stash
   // this frame.
   uint16_t last_picture_id_gop = seq_num_it->second.first;
   uint16_t last_picture_id_with_padding_gop = seq_num_it->second.second;
   if (frame->frame_type() == kVideoFrameDelta) {
     uint16_t prev_seq_num = frame->first_seq_num() - 1;
-    if (prev_seq_num != last_picture_id_with_padding_gop) {
-      stashed_frames_.push_back(std::move(frame));
-      return;
-    }
+
+    if (prev_seq_num != last_picture_id_with_padding_gop)
+      return kStash;
   }
 
   RTC_DCHECK(AheadOrAt(frame->last_seq_num(), seq_num_it->first));
 
   // Since keyframes can cause reordering we can't simply assign the
   // picture id according to some incrementing counter.
   frame->picture_id = frame->last_seq_num();
   frame->num_references = frame->frame_type() == kVideoFrameDelta;
   frame->references[0] = last_picture_id_gop;
   if (AheadOf(frame->picture_id, last_picture_id_gop)) {
     seq_num_it->second.first = frame->picture_id;
     seq_num_it->second.second = frame->picture_id;
   }
 
   last_picture_id_ = frame->picture_id;
   UpdateLastPictureIdWithPadding(frame->picture_id);
-  frame_callback_->OnCompleteFrame(std::move(frame));
-  RetryStashedFrames();
+  return kHandOff;
 }
 
-void RtpFrameReferenceFinder::ManageFrameVp8(
-    std::unique_ptr<RtpFrameObject> frame) {
+RtpFrameReferenceFinder::FrameDecision RtpFrameReferenceFinder::ManageFrameVp8(
+    RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
   if (!rtp_codec_header)
-    return;
+    return kDrop;
 
   const RTPVideoHeaderVP8& codec_header = rtp_codec_header->VP8;
 
   if (codec_header.pictureId == kNoPictureId ||
       codec_header.temporalIdx == kNoTemporalIdx ||
       codec_header.tl0PicIdx == kNoTl0PicIdx) {
-    ManageFrameGeneric(std::move(frame), codec_header.pictureId);
-    return;
+    return ManageFrameGeneric(std::move(frame), codec_header.pictureId);
   }
 
   frame->picture_id = codec_header.pictureId % kPicIdLength;
 
   if (last_unwrap_ == -1)
     last_unwrap_ = codec_header.pictureId;
 
   if (last_picture_id_ == -1)
     last_picture_id_ = frame->picture_id;
 
@@ skipping 15 matching lines @@
   // Clean up info about not yet received frames that are too old.
   uint16_t old_picture_id =
       Subtract<kPicIdLength>(frame->picture_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);
 
   if (frame->frame_type() == kVideoFrameKey) {
     frame->num_references = 0;
     layer_info_[codec_header.tl0PicIdx].fill(-1);
-    CompletedFrameVp8(std::move(frame));
-    return;
+    UpdateLayerInfoVp8(frame);
+    return kHandOff;
   }
 
   auto layer_info_it = layer_info_.find(codec_header.temporalIdx == 0
                                             ? codec_header.tl0PicIdx - 1
                                             : codec_header.tl0PicIdx);
 
   // If we don't have the base layer frame yet, stash this frame.
-  if (layer_info_it == layer_info_.end()) {
-    stashed_frames_.push_back(std::move(frame));
-    return;
-  }
+  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_
             .insert(make_pair(codec_header.tl0PicIdx, layer_info_it->second))
             .first;
     frame->num_references = 1;
     frame->references[0] = layer_info_it->second[0];
-    CompletedFrameVp8(std::move(frame));
-    return;
+    UpdateLayerInfoVp8(frame);
+    return kHandOff;
   }
 
   // Layer sync frame, this frame only references its base layer frame.
   if (codec_header.layerSync) {
     frame->num_references = 1;
     frame->references[0] = layer_info_it->second[0];
 
-    CompletedFrameVp8(std::move(frame));
-    return;
+    UpdateLayerInfoVp8(frame);
+    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) {
-      stashed_frames_.push_back(std::move(frame));
-      return;
-    }
+    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, kPicIdLength>(layer_info_it->second[layer],
                                         frame->picture_id)) {
-      return;
+      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, kPicIdLength>(frame->picture_id,
                                         *not_received_frame_it)) {
-      stashed_frames_.push_back(std::move(frame));
-      return;
+      return kStash;
     }
 
     if (!(AheadOf<uint16_t, kPicIdLength>(frame->picture_id,
                                           layer_info_it->second[layer]))) {
       LOG(LS_WARNING) << "Frame with picture id " << frame->picture_id
                       << " and packet range [" << frame->first_seq_num() << ", "
                       << frame->last_seq_num() << "] already received, "
                       << " dropping frame.";
-      return;
+      return kDrop;
     }
 
     ++frame->num_references;
     frame->references[layer] = layer_info_it->second[layer];
   }
 
-  CompletedFrameVp8(std::move(frame));
+  UpdateLayerInfoVp8(frame);
+  return kHandOff;
 }
 
-void RtpFrameReferenceFinder::CompletedFrameVp8(
-    std::unique_ptr<RtpFrameObject> frame) {
+void RtpFrameReferenceFinder::UpdateLayerInfoVp8(RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
-  if (!rtp_codec_header)
-    return;
-
+  RTC_DCHECK(rtp_codec_header);
   const RTPVideoHeaderVP8& codec_header = rtp_codec_header->VP8;
 
   uint8_t tl0_pic_idx = codec_header.tl0PicIdx;
   uint8_t temporal_index = codec_header.temporalIdx;
   auto layer_info_it = layer_info_.find(tl0_pic_idx);
 
   // Update this layer info and newer.
   while (layer_info_it != layer_info_.end()) {
     if (layer_info_it->second[temporal_index] != -1 &&
         AheadOf<uint16_t, kPicIdLength>(layer_info_it->second[temporal_index],
                                         frame->picture_id)) {
       // The frame was not newer, then no subsequent layer info have to be
       // update.
       break;
     }
 
     layer_info_it->second[codec_header.temporalIdx] = frame->picture_id;
     ++tl0_pic_idx;
     layer_info_it = layer_info_.find(tl0_pic_idx);
   }
   not_yet_received_frames_.erase(frame->picture_id);
 
-  for (size_t i = 0; i < frame->num_references; ++i)
-    frame->references[i] = UnwrapPictureId(frame->references[i]);
-  frame->picture_id = UnwrapPictureId(frame->picture_id);
-
-  frame_callback_->OnCompleteFrame(std::move(frame));
-  RetryStashedFrames();
+  UnwrapPictureIds(frame);
 }
 
-void RtpFrameReferenceFinder::ManageFrameVp9(
-    std::unique_ptr<RtpFrameObject> frame) {
+RtpFrameReferenceFinder::FrameDecision RtpFrameReferenceFinder::ManageFrameVp9(
+    RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
-  if (!rtp_codec_header)
-    return;
-
+  RTC_DCHECK(rtp_codec_header);
   const RTPVideoHeaderVP9& codec_header = rtp_codec_header->VP9;
 
   bool old_frame = Vp9PidTl0Fix(*frame, &rtp_codec_header->VP9.picture_id,
                                 &rtp_codec_header->VP9.tl0_pic_idx);
   if (old_frame)
-    return;
+    return kDrop;
 
   if (codec_header.picture_id == kNoPictureId ||
       codec_header.temporal_idx == kNoTemporalIdx) {
-    ManageFrameGeneric(std::move(frame), codec_header.picture_id);
-    return;
+    return ManageFrameGeneric(std::move(frame), codec_header.picture_id);
   }
 
   frame->spatial_layer = codec_header.spatial_idx;
   frame->inter_layer_predicted = codec_header.inter_layer_predicted;
   frame->picture_id = codec_header.picture_id % kPicIdLength;
 
   if (last_unwrap_ == -1)
     last_unwrap_ = codec_header.picture_id;
 
   if (last_picture_id_ == -1)
     last_picture_id_ = frame->picture_id;
 
   if (codec_header.flexible_mode) {
     frame->num_references = codec_header.num_ref_pics;
     for (size_t i = 0; i < frame->num_references; ++i) {
       frame->references[i] =
           Subtract<1 << 16>(frame->picture_id, codec_header.pid_diff[i]);
     }
 
-    CompletedFrameVp9(std::move(frame));
-    return;
+    UnwrapPictureIds(frame);
+    return kHandOff;
   }
 
   if (codec_header.ss_data_available) {
     // Scalability structures can only be sent with tl0 frames.
     if (codec_header.temporal_idx != 0) {
       LOG(LS_WARNING) << "Received scalability structure on a non base layer"
                          " frame. Scalability structure ignored.";
     } else {
       current_ss_idx_ = Add<kMaxGofSaved>(current_ss_idx_, 1);
       scalability_structures_[current_ss_idx_] = codec_header.gof;
@@ skipping 11 matching lines @@
   gof_info_.erase(gof_info_.begin(), clean_gof_info_to);
 
   if (frame->frame_type() == kVideoFrameKey) {
     // When using GOF all keyframes must include the scalability structure.
     if (!codec_header.ss_data_available)
       LOG(LS_WARNING) << "Received keyframe without scalability structure";
 
     frame->num_references = 0;
     GofInfo info = gof_info_.find(codec_header.tl0_pic_idx)->second;
     FrameReceivedVp9(frame->picture_id, &info);
-    CompletedFrameVp9(std::move(frame));
-    return;
+    UnwrapPictureIds(frame);
+    return kHandOff;
   }
 
   auto gof_info_it = gof_info_.find(
       (codec_header.temporal_idx == 0 && !codec_header.ss_data_available)
           ? codec_header.tl0_pic_idx - 1
           : codec_header.tl0_pic_idx);
 
   // Gof info for this frame is not available yet, stash this frame.
-  if (gof_info_it == gof_info_.end()) {
-    stashed_frames_.push_back(std::move(frame));
-    return;
-  }
+  if (gof_info_it == gof_info_.end())
+    return kStash;
 
   GofInfo* info = &gof_info_it->second;
   FrameReceivedVp9(frame->picture_id, info);
 
   // Make sure we don't miss any frame that could potentially have the
   // up switch flag set.
-  if (MissingRequiredFrameVp9(frame->picture_id, *info)) {
-    stashed_frames_.push_back(std::move(frame));
-    return;
-  }
+  if (MissingRequiredFrameVp9(frame->picture_id, *info))
+    return kStash;
 
   if (codec_header.temporal_up_switch) {
     auto pid_tidx =
         std::make_pair(frame->picture_id, codec_header.temporal_idx);
     up_switch_.insert(pid_tidx);
   }
 
   // If this is a base layer frame that contains a scalability structure
   // then gof info has already been inserted earlier, so we only want to
   // insert if we haven't done so already.
@@ skipping 18 matching lines @@
         frame->picture_id, info->gof->pid_diff[gof_idx][i]);
 
     // If this is a reference to a frame earlier than the last up switch point,
     // then ignore this reference.
     if (UpSwitchInIntervalVp9(frame->picture_id, codec_header.temporal_idx,
                               frame->references[i])) {
       --frame->num_references;
     }
   }
 
-  CompletedFrameVp9(std::move(frame));
+  UnwrapPictureIds(frame);
+  return kHandOff;
 }
 
 bool RtpFrameReferenceFinder::MissingRequiredFrameVp9(uint16_t picture_id,
                                                       const GofInfo& info) {
   size_t diff =
       ForwardDiff<uint16_t, kPicIdLength>(info.gof->pid_start, picture_id);
   size_t gof_idx = diff % info.gof->num_frames_in_gof;
   size_t temporal_idx = info.gof->temporal_idx[gof_idx];
 
   // For every reference this frame has, check if there is a frame missing in
@@ skipping 51 matching lines @@
        up_switch_it != up_switch_.end() &&
        AheadOf<uint16_t, kPicIdLength>(picture_id, up_switch_it->first);
        ++up_switch_it) {
     if (up_switch_it->second < temporal_idx)
       return true;
   }
 
   return false;
 }
 
-void RtpFrameReferenceFinder::CompletedFrameVp9(
-    std::unique_ptr<RtpFrameObject> frame) {
+void RtpFrameReferenceFinder::UnwrapPictureIds(RtpFrameObject* frame) {
   for (size_t i = 0; i < frame->num_references; ++i)
     frame->references[i] = UnwrapPictureId(frame->references[i]);
   frame->picture_id = UnwrapPictureId(frame->picture_id);
-
-  frame_callback_->OnCompleteFrame(std::move(frame));
-  RetryStashedFrames();
 }
 
 uint16_t RtpFrameReferenceFinder::UnwrapPictureId(uint16_t picture_id) {
   RTC_DCHECK_NE(-1, last_unwrap_);
 
   uint16_t unwrap_truncated = last_unwrap_ % kPicIdLength;
   uint16_t diff = MinDiff<uint16_t, kPicIdLength>(unwrap_truncated, picture_id);
 
   if (AheadOf<uint16_t, kPicIdLength>(picture_id, unwrap_truncated))
     last_unwrap_ = Add<1 << 16>(last_unwrap_, diff);
@@ skipping 141 matching lines @@
     if (!gof_info_.empty() &&
         AheadOf<uint8_t>(gof_info_.begin()->first, fixed_tl0)) {
       return true;
     }
   }
   return false;
 }
 
 }  // namespace video_coding
 }  // namespace webrtc