Avoid creating frames with packets of different timestamps.

Bug: None
Change-Id: Ieca71f844d546c2e97b95131153913f138842acd
Reviewed-on: https://webrtc-review.googlesource.com/c/116680
Reviewed-by: Ilya Nikolaevskiy <ilnik@webrtc.org>
Commit-Queue: Philip Eliasson <philipel@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26176}
diff --git a/modules/video_coding/packet_buffer.cc b/modules/video_coding/packet_buffer.cc
index 80c6666..4ef0b00 100644
--- a/modules/video_coding/packet_buffer.cc
+++ b/modules/video_coding/packet_buffer.cc
@@ -266,6 +266,8 @@
       static_cast<uint16_t>(sequence_buffer_[index].seq_num - 1)) {
     return false;
   }
+  if (data_buffer_[prev_index].timestamp != data_buffer_[index].timestamp)
+    return false;
   if (sequence_buffer_[prev_index].continuous)
     return true;