The Media Resource Control Protocol is a standard method for communicating across multiple applications. It is used primarily for telephony platforms to control applications like automatic speech recognition engines (ASR) and text-to-speech engines (TTS). MRCP provides a standards-based alternative to API-level integration of these resources. For more information, please see our whitepaper describing the differences between API and MRCP integrations.
For information about configuring the LumenVox Speech Engine and MRCP Server with a third-party voice platform, please see our guide to setting up LumenVox with voice platforms.
Note that you will not need to use MRCP if your platform has already done an API-level integration of LumenVox. If you are uncertain, please contact your platform provider or LumenVox technical support for more information.
In order to use the LumenVox Speech Engine over MRCP, you must install the ASR/TTS and License Server as usual, but you must also install the LumenVox Media Server (on Windows this is included with the Speech Engine installation package). This server sits between an MRCP client (the application platform) and the ASR and TTS, handling MRCP communications from the client and passing requests to the speech resource servers.
MRCP comes in two versions, version one and version two. The two are similar, but incompatible. MRCPv1 uses RTSP as its session control protocol while MRCPv2 uses SIP. The LumenVox Media Server is designed to handle either or both protocols.
For the complete MRCPv1 specification, you may refer to RFC #4463. MRCPv2 is still a working draft, but the latest revision is available online.
As of LumenVox Speech Engine 9.0, the Media Server is used for both MRCPv1 and MRCPv2 support. Our legacy MRCPv1 Server was deprecated at that point and officially unsupported in releases after version 9.5.
To get started working with MRCP, please see Installing the Media Server.
Note: In order for the Media Server to work properly, you MUST point the Media Server config file's mrcp_server_ip value from the loop back address to the actual IP address of the machine running the Media Server. This information is used in the MRCP packets sent to the client. More can be read on this here.