Why you wont hear jitter when listening to a call from a PCAP

An employee was noted that our monitoring system must be broken since it said there was jitter on the call yet if we extract the audio from the RTP packets the call sounds normal. I wrote up a small summary which I thought would help others so here it is.

If the packets are out of order when playing them back, since we have all of them (if there is no packet loss) then it will play it in the right order. If I send the word HELLO one letter at a time in 5 separate packets, so long as the letters are numbered you will be able to re-assemble them in the right order. For instance if you get the packets in this order:

First packet        1) H
Second Packet    5) O
Third packet       4) L
Fourth packet     3) L
Fifth packet        2) E

And you re-assemble them in the order of 1-5 you will get:
1) H
2) E
3) L
4) L
5) O

So when playing back the media you will hear hello.

However imagine if that is a phone call and the packets came in the original order the person would hear:
1) H
5) O

The reason being because we get packet 1 so we play H the next packet we get is packet 5 which is O. The next packet we get is packet #4. There is no need to play this packet since we are passed this point. If we played every packet we got the person would hear HOLLE.