[FMS] RTMP, RTMFP

Media/WOWZA 2012. 9. 13. 10:43

RTMFP(Real Time Meida Flow Protocol)은 Adobe에서 Adobe Flash Players와 LCCS나 Adobe AIR framework로 만들어진 어플리케이션 사이에 end user가 end user에게 peering통신을 가능하게 하는 새로운 프로토콜입니다. RTMFP는 소셜네트워크나, 고품질 솔루션을 전송하는 멀티유져 게임과 같은 실시간 커뮤니케이션을 가능하게 합니다. RTMFP는 end user사이에 마이크와 웹캠을 사용하면서 직접적으로 통신이 가능하게 한다.

Real Time Media Flow Protocol (RTMFP) is a new protocol from Adobe that enables direct end user to end user peering communication between multiple Adobe Flash Players and applications built on LCCS or the Adobe AIR framework. RTMFP enables real time communication applications such as social networks and multi-user games to deliver high quality solutions. RTMFP enables end users to connect and communicate directly with each other using their computer's microphone and webcam.

 

RTMFP는 UDP(User Datagram Protocaol) 기반으로 되어있는 반면, RTMP는 TCP(Transmission Control Protocaol)기반으로 되어있습다.  UDP기반의 프로토콜은 TCP를 기반으로하는 프로토콜 보다 더 많은 이점을 가질 수 있습니다.   latency와 overhead의 감소뿐만 아니라, 더 뛰어난 missing packets에 대한 tolerance를 가지는 라이브 스트리밍 미디어를 전송할 수 있습니다.  serverside 커넥션은 end user사이에서 항상 connection초기화를 해야 합니다. 그리고 serverside 데이터,혹은 다른 시스템으로의 게이트웨이들을 제공할때 사용할 수 있습니다.

RTMFP is based on the User Datagram Protocol (UDP), whereas RTMP is based on the Transmission Control Protocol (TCP). UDP-based protocols have many advantages over TCP-based protocols when delivering live streaming media, including decreased latency and overhead as well as greater tolerance for missing packets.

A server side connection is always required to establish the initial connection between the end users and can be used to provide server side data execution or gateways into other systems.

 

 

RTMP(TCP기반)은 라이브스트리밍에 대해 좀 더 작은 허브와 spoke model(?)을 사용한다. RTMFP는 전송실패시 재전송되어진 오디오와 비디오 패킷을 강제하지 않는다.(?)

RTMFP는 Data Gap이 있음에도 계속해서 전송된다. 이것은 저손실 패킷전송에 좀 더 부드러운 재생이 가능하게 한다. 또한 clinet와 client 사이에서의 스트리밍도 지원한다.

client와 client는 free(?)가 아니다. 또한 더 빠르다. 이것은 LCCS service 통해 routed되지 않기 때문입니다. 많은 사용자나 방화벽, 다른 네트워크 상태에 따라 RTMFP 사용은 제한적일 것입니다. LCCS는 상황에 따라 자동적으로 바뀌도록 설계되었습니다. 만약 RTMFP가 사용가능하면 RTMFP를 사용하고, 그렇지 않으면 RTMP를 사용합니다.

RTMP (TCP) uses a hub and spoke model which is less than ideal for live streaming. RTMFP doesn't force audio and video packets to be retransmitted in the case of failure. It continues playing despite gaps in the data - this means that the stream plays more smoothly in the case of small-scale packet loss. It also supports client to client streaming.

Client to client streaming is not only free; it's also faster, because it isn't routed through the LCCS service. However, since a high number of users, a firewall, or other network conditions may prohibit the use of RTMFP, LCCS has been designed to automatically switch based on conditions: if RTMFP is enabled it uses it; if not, it uses RTMP.

 

  RTMFP는 우선적인 프로토콜이고, Flash player 10 SWC가 허영되는 한에 항상 더 나은 선택을 합니다. 왜냐하면 LCCS는 두 프로토콜들 사이에서 자동적으로 바꿀 수 있을 만큼 똑똑합니다. 그리고 you can always leverage RTMFP's capabilities whenever it's possible to do so and use RTMP as a fallback.

  RTMFP is the preferred protocol and always a better choice if using the required Flash player 10 SWC is acceptable. Because LCCS is smart enough to automatically switch between the two protocols as needed, you can always leverage RTMFP's capabilities whenever it's possible to do so and use RTMP as a fallback.

To use RTMFP, set your project to use the Flash Player 10 or 10.1 SWC files.

RTMFP pros

  • Client to client streaming: C2C reduces latency, since there are fewer hops from source to destination. The advantages for the LCCS service as well as you, is that the service can operate with less infrastructure to allow you to stream, thereby increasing reliability.
  • Speex access through Flash Player 10: Speex is a better codec than the NellyMoser codec in older Flash Players because it encodes voice with higher quality and at a lower bitrate. It's also more compatible with UDP so that it handles lossiness relatively gracefully.
  • Reduced bandwidth costs: RTMFP reduces the bandwidth costs for direct real time communication solutions such as audio and video chat and multiplayer games. Because RTMFP flows data between end user clients rather than the server, server bandwidth is reduced, thereby making solutions are less expensive to scale.
  • Increased speed of delivery: RTMFP also increases the speed of delivery through the use of UDP. UDP is a more efficient (but less reliable) way to send video and audio data over the Internet because it reduces the penalties associated with missing, dropped, or out of order packets.
  • Superior connection error recovery: RTMFP has two features that may help to mitigate the effects of connection errors:
    • Rapid Connection Restore: Connections are reestablished quickly after brief outages such as when a wireless network connection experiences a dropout. After re-connection, the connection has full capabilities instantly.
    • IP Mobility: Active network peer sessions are maintained even if a client changes to a new IP address. For example, when a laptop on a wireless network is plugged into a wired connection and receives a new network address.

RTMFP cons

Requires Flash player 10. This is usually a good thing.

 

*source : http://learn.adobe.com/wiki/display/lccs/8.4+RTMFP+vs+RTMP

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