From e203de7ba2631d50dc880a137444f1d5c134a033 Mon Sep 17 00:00:00 2001
From: "mikhal@webrtc.org"
 <mikhal@webrtc.org@4adac7df-926f-26a2-2b94-8c16560cd09d>
Date: Thu, 3 Nov 2011 00:42:52 +0000
Subject: [PATCH] jitter_buffer updates: 1. Determining continuity based on
 pictureId and not seq. numbers when available. 2. Hybrid bug fix: Don't set
 to decodable when the nack list is empty. Review URL:
 http://webrtc-codereview.appspot.com/255001

git-svn-id: http://webrtc.googlecode.com/svn/trunk@878 4adac7df-926f-26a2-2b94-8c16560cd09d
---
 .../video_coding/main/source/jitter_buffer.cc | 44 +++++++++++--------
 .../video_coding/main/source/session_info.cc  |  9 +---
 2 files changed, 28 insertions(+), 25 deletions(-)

diff --git a/src/modules/video_coding/main/source/jitter_buffer.cc b/src/modules/video_coding/main/source/jitter_buffer.cc
index aa894a70f..156c0d3cb 100644
--- a/src/modules/video_coding/main/source/jitter_buffer.cc
+++ b/src/modules/video_coding/main/source/jitter_buffer.cc
@@ -614,26 +614,33 @@ VCMJitterBuffer::FindOldestCompleteContinuousFrame()
 
     // we have a complete frame
     // check if it's continuous, otherwise we are missing a full frame
-    // Use seqNum not timestamp since a full frame might be lost
-    if (_lastDecodedSeqNum != -1 && !_waitingForKeyFrame)
-    {
-        // it's not enough that we have complete frame we need the layers to
-        // be continuous too
-        currentLow = oldestFrame->GetLowSeqNum();
 
-        WebRtc_UWord16 lastDecodedSeqNum = (WebRtc_UWord16)_lastDecodedSeqNum;
-
-        // We could have received the first packet of the last frame before a
-        // long period if drop, that case is handled by GetNackList
-        if (((WebRtc_UWord16)(lastDecodedSeqNum + 1)) != currentLow)
-        {
-            // Wait since we want a complete continuous frame
-            return NULL;
-        }
+    // Use pictureId if available. Otherwise use seqNum and not timestamps, as
+    // a complete frame might be lost
+    // First determine if we are waiting for a key frame.
+    if (_waitingForKeyFrame && oldestFrame->FrameType() != kVideoFrameKey)  {
+      return NULL;
     }
-    else if (oldestFrame->FrameType() != kVideoFrameKey)
-    {
+    // Is this the first frame to be decoded?
+    // Otherwise, verify continuity - use PictureId when available.
+    if (_lastDecodedSeqNum == -1)  {
+      return oldestFrameItem;
+    } else if (oldestFrame->PictureId() == kNoPictureId)  {
+      // It's not enough that we have a complete frame we need the layers to
+      // be continuous too.
+      currentLow = oldestFrame->GetLowSeqNum();
+      WebRtc_UWord16 lastDecodedSeqNum = (WebRtc_UWord16)_lastDecodedSeqNum;
+
+      // We could have received the first packet of the last frame before a
+      // long period if drop, that case is handled by GetNackList
+      if (((WebRtc_UWord16)(lastDecodedSeqNum + 1)) != currentLow)  {
+        // Wait since we want a complete continuous frame
         return NULL;
+      }
+    }
+    else if (!ContinuousPictureId(oldestFrame->PictureId()))  {
+      // We don't have a continuous frame
+      return NULL;
     }
     return oldestFrameItem;
 }
@@ -1460,10 +1467,11 @@ VCMJitterBuffer::CreateNackList(WebRtc_UWord16& nackSize, bool& listExtended)
             {
                 // build external rttScore based on RTT value
                 float rttScore = 1.0f;
+                int ret =
                 _frameBuffers[i]->ZeroOutSeqNumHybrid(_NACKSeqNumInternal,
                                                       numberOfSeqNum,
                                                       rttScore);
-                if (_frameBuffers[i]->IsRetransmitted() == false)
+                if (_frameBuffers[i]->IsRetransmitted() == false && ret != -1)
                 {
                     // If no retransmission required,set the state to decodable
                     // meaning that we will not wait for NACK.
diff --git a/src/modules/video_coding/main/source/session_info.cc b/src/modules/video_coding/main/source/session_info.cc
index cbfcf2273..799a5d3e7 100644
--- a/src/modules/video_coding/main/source/session_info.cc
+++ b/src/modules/video_coding/main/source/session_info.cc
@@ -491,7 +491,7 @@ WebRtc_Word32
 VCMSessionInfo::ZeroOutSeqNum(WebRtc_Word32* list,
                               WebRtc_Word32 numberOfSeqNum)
 {
-    if ((NULL == list) || (numberOfSeqNum < 1))
+    if (NULL == list || numberOfSeqNum < 1)
     {
         return -1;
     }
@@ -539,15 +539,10 @@ VCMSessionInfo::ZeroOutSeqNumHybrid(WebRtc_Word32* list,
                                     WebRtc_Word32 numberOfSeqNum,
                                     float rttScore)
 {
-    if ((NULL == list) || (numberOfSeqNum < 1))
+    if (NULL == list || numberOfSeqNum < 1)
     {
         return -1;
     }
-    if (_lowSeqNum == -1)
-    {
-        // no media packets in this frame
-        return 0;
-    }
 
     WebRtc_Word32 index = 0;
     // Find end point (index of entry that equals _lowSeqNum)