Merge pull request mavlink#696 from Susurrus/fix_647

Fix for mavlink#647

src/ui/QGCMAVLinkLogPlayer.cc

@@ -572,10 +572,18 @@ void QGCMAVLinkLogPlayer::logLoop()
  if (mavlinkLogFormat)
  {
  // Now parse MAVLink messages, grabbing their timestamps as we go. We stop once we
- // have at least 3ms until the next one.
+ // have at least 3ms until the next one. 
+
+ // We track what the next execution time should be in milliseconds, which we use to set
+ // the next timer interrupt.
  int nextExecutionTime = 0;
+
+ // We use the `findNextMavlinkMessage()` function to scan ahead for MAVLink messages. This
+ // is necessary because we don't know how big each MAVLink message is until we finish parsing
+ // one, and since we only output arrays of bytes, we need to know the size of that array.
  mavlink_message_t msg;
- msg.len = 0; // FIXME: Hack, remove once Issue #647 is fixed
+ findNextMavlinkMessage(&msg);
+
  while (nextExecutionTime < 3) {
 
  // Now we're sitting at the start of a MAVLink message, so read it all into a byte array for feeding to our parser.