Unwrap picture ids in the RtpFrameReferencerFinder.

webrtc/modules/video_coding/rtp_frame_reference_finder.cc

Index: webrtc/modules/video_coding/rtp_frame_reference_finder.cc
diff --git a/webrtc/modules/video_coding/rtp_frame_reference_finder.cc b/webrtc/modules/video_coding/rtp_frame_reference_finder.cc
index 8d74c363c511b07420f961e75f93e152c8df71df..970d3e98301f44717443e02ff5d1d2ba35fff26e 100644
--- a/webrtc/modules/video_coding/rtp_frame_reference_finder.cc
+++ b/webrtc/modules/video_coding/rtp_frame_reference_finder.cc
@@ -27,7 +27,9 @@ RtpFrameReferenceFinder::RtpFrameReferenceFinder(
       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) {
@@ -176,7 +178,7 @@ RtpFrameReferenceFinder::ManageFrameGeneric(RtpFrameObject* frame,
     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;
@@ -228,14 +230,15 @@ RtpFrameReferenceFinder::ManageFrameGeneric(RtpFrameObject* frame,
   // 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;
 }
 
@@ -367,7 +370,6 @@ 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);
@@ -394,7 +396,8 @@ void RtpFrameReferenceFinder::UpdateLayerInfoVp8(RtpFrameObject* 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 ||
@@ -585,22 +588,8 @@ bool RtpFrameReferenceFinder::UpSwitchInIntervalVp9(uint16_t picture_id,
 
 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