Rob,
Jon has provided you already with a wonderful explanation about the UDP/RTP difference. Please let me add my few thoughts on this.
From a programmer's or developer's perspective, the RTP is not another "driver" - just as Jon said, it sits atop of UDP and is usually implemented as a library used from within userspace. What it does is providing you with additional capabilities that the UDP alone cannot provide you with:
- Identification of the payload type
- Identification of stream sources in a protocol-neutral way (the SSRC and CSRC fields)
- Identification of important frames (for sync purposes, for example)
- Sequencing used to detect lost and reordered segments
- Timestamping to synchronize and correlate multiple streams (video and audio, for example)
Note however that the RTP does only provide you with these facilities but it is up to you to make use of them. For example, RTP alone won't perform automatic timestamping or sequence number assignment - it is up to your application to provide it. From this perspective, the RTP is like a framework that can be used in different ways, according to developer needs.
If you are not planning to develop a software application but rather having a working solution already that supports both UDP and RTP then it is difficult to say whether using UDP or RTP is going to be better - it depends exclusively on the application whether it is able to make use of the RTP benefits, or whether it merely uses it just as another layer of packaging.
Best regards,
Peter
