In today’s video, owner of Antrica, Les Litwin explains the differences between RTSP and MPEG-TS and how this can affect your ability to encode and decode.
So today, we’re talking about RTSP and MPEG transport stream, MPEG-TS as it is referred to. These are two streaming protocols, generally used in broadcast and security.
RTSP is very popular in security and surveillance and MPEG-TS is extremely popular in the broadcast market, but in some applications, you may have the need to use one or other, so let me explain the differences.
RTSP comes in two flavours, there’s RTSP over UDP and there’s RTSP over TCP. I would say 90% of applications use RTSP over TCP because that’s a two-way streaming format where there’s an ability for the client, or the decoder to be able to handshake with the encoder and the encoder can then stream to the decoder so that’s what I mean by two-way.
The way this works is that the client communicates with the encoder and says ‘please send me a stream’ and the encoder then generates that stream and sends it to the client. If a second client comes onto the network, that second client can also access the encoder and request another stream to be sent so now the encoder is generating two streams, one for each client, the bit rate has gone up by a factor of two because each stream that is generated increases the bitrate.
The MPEG-TS is completely different. MPEG-TS works over UDP, so it’s a one-way streaming format and the way MPEG-TS works is that you have to tell the encoder what is the IP address of the decoder and it will send that stream specifically to that IP address. There is no opportunity for another decoder to then connect up and ask for a stream, there is only one stream and it’s literally from the encoder to the decoder.
So that’s the difference between RTSP over TCP because you can support multiple clients and MPEG-TS where you can only support one client.
Now having said that, there is a limit, RTSP over TCP, the encoder can only generate so many streams and that depends on a lot of things, it can generate one stream, two streams, or maybe twenty streams, but that’s sort of the encoder dependent. With the MPEG-TS mode, you can only generate one. The way you overcome this in both modes to support more and more clients is you have to go multicast, and once you go into the multicast world then it’s it’s a completely different subject and we’ve actually done a little block on multicasting. So anyway, those are the differences between RTSP and MPEG-TS.