Using a simple tcpreplay e.g.

sudo src/tcpreplay -K test.pcap

If I record another PCAP of the playout, the packets in the playout happen later and later compared to the original test.pcap. The reason is that the timing is all done using deltas between packets and errors in timing accumulate. This has a huge impact on playback of time sensitive PCAPs e.g. UDP video containing PCR timestamps.

I have a suggested patch for this which switches to comparing times since the first packet was sent.