Unwrap picture ids in the RtpFrameReferencerFinder.

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.
  */
 
 #include "webrtc/modules/video_coding/rtp_frame_reference_finder.h"
 
 #include <algorithm>
 #include <limits>
 
 #include "webrtc/modules/video_coding/frame_object.h"
 #include "webrtc/modules/video_coding/packet_buffer.h"
 #include "webrtc/rtc_base/checks.h"
 #include "webrtc/rtc_base/logging.h"
 
 namespace webrtc {
 namespace video_coding {
 
 RtpFrameReferenceFinder::RtpFrameReferenceFinder(
     OnCompleteFrameCallback* frame_callback)
     : last_picture_id_(-1),
       last_unwrap_(-1),
       current_ss_idx_(0),
       cleared_to_seq_num_(-1),
-      frame_callback_(frame_callback) {}
+      frame_callback_(frame_callback),
+      generic_unwrapper_(100000),

[terelius, 2017/08/18 11:53:16]

Is this the starting point for unwrapped numbers? If so, is there a reason for
not taking something close to 2**62?

[philipel, 2017/08/24 10:46:10]

Changed the SeqNumUnwrapper default start value to 10000000000000000000UL, which
is larger than 2^63 and smaller than 2^64.

+      unwrapper_(100000) {}
 
 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;
   }
@@ skipping 128 matching lines @@
 
 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->picture_id = unwrapper_.Unwrap(picture_id);
     frame->num_references = frame->frame_type() == kVideoFrameKey ? 0 : 1;
     frame->references[0] = frame->picture_id - 1;
     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())));
   }
@@ skipping 31 matching lines @@
     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)) {
+  frame->references[0] = generic_unwrapper_.Unwrap(last_picture_id_gop);
+  if (AheadOf<uint16_t>(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->picture_id = generic_unwrapper_.Unwrap(frame->picture_id);
   return kHandOff;
 }
 
 RtpFrameReferenceFinder::FrameDecision RtpFrameReferenceFinder::ManageFrameVp8(
     RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
   if (!rtp_codec_header)
     return kDrop;
 
   const RTPVideoHeaderVP8& codec_header = rtp_codec_header->VP8;
@@ skipping 111 matching lines @@
   }
 
   UpdateLayerInfoVp8(frame);
   return kHandOff;
 }
 
 void RtpFrameReferenceFinder::UpdateLayerInfoVp8(RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
   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);
 
   UnwrapPictureIds(frame);
 }
 
 RtpFrameReferenceFinder::FrameDecision RtpFrameReferenceFinder::ManageFrameVp9(
     RtpFrameObject* frame) {
   rtc::Optional<RTPVideoTypeHeader> rtp_codec_header = frame->GetCodecHeader();
-  RTC_DCHECK(rtp_codec_header);
+  if (!rtp_codec_header)
+    return kDrop;
   const RTPVideoHeaderVP9& codec_header = rtp_codec_header->VP9;
 
   if (codec_header.picture_id == kNoPictureId ||
       codec_header.temporal_idx == kNoTemporalIdx) {
     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;
@@ skipping 170 matching lines @@
        ++up_switch_it) {
     if (up_switch_it->second < temporal_idx)
       return true;
   }
 
   return false;
 }
 
 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);
-}
-
-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);
-  else
-    last_unwrap_ = Subtract<1 << 16>(last_unwrap_, diff);
-
-  return last_unwrap_;
+    frame->references[i] = unwrapper_.Unwrap(frame->references[i]);
+  frame->picture_id = unwrapper_.Unwrap(frame->picture_id);
 }
 
 }  // namespace video_coding
 }  // namespace webrtc